(hcpb) test blanket module

Transcription

FUS-TN-SA-SE-R-152
ENTE PER LE NUOVE TECNOLOGIE, L'ENERGIA E L'AMBIENTE
Associazione ENEA-EURATOM sulla Fusione
FUSION DIVISION
NUCLEAR FUSION TECHNOLOGIES
FAILURE MODE AND EFFECT ANALYSIS FOR THE
EUROPEAN HELIUM COOLED PEBBLE BED (HCPB)
TEST BLANKET MODULE
Final Report EFDA Task TW6-TTBB-001
T. Pinna (1)
(1)
Thermonuclear Fusion Unit - Safety & Environment
Via E. Fermi 45, I-00044, Frascati (Rome), Italy e-mail: [email protected]
October 2006
Title:
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Failure Mode and Effect Analysis for the European Helium
Cooled Pebble Bed (HCPB) Test Blanket Module
European Fusion Development Agreement Workprogramme 2006
Reference:
EFDA Task TW6-TTBB-001
Authors:
T. Pinna (ENEA FPN FUSTEC, C.R.E. Frascati)
Scope:
A Failure Mode and Effect Analysis (FMEA) of the European
Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) has
been performed based on design information updated July 2006.
The PI-TBM (Plant Integration module), which will operate in the
last period of the high duty cycle D-T phase of ITER-FEAT life, has
been considered in the assessment because it is the most
representative from a safety point of view.
The analysis has been performed for the Burning and Dwell
operating phases, the so called “Normal Operation”.
As a result of the FMEA a set of Postulated Initiating Events (PIEs)
to be taken into account in the deterministic transient analyses has
been defined. The PIEs have been discussed to qualitatively define
possible accident evolutions.
The total number of PIEs pointed out by assessing elementary
failures related to the different TBM components is 21.
Detailed tables are reported about: list of components; possible
failure modes of components together with related causes,
consequences and preventive/mitigating actions; list of PIEs with
related contributors.
Signatures
Emitted by
Revised by
Approved by
T. Pinna
M.T. Porfiri
A. Pizzuto
Distribution list:
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A. Renieri, Fusion Division (ENEA, FPN FUS Frascati, Italy)
Technologies (ENEA, FPN FUSTEC Frascati, Italy)
A. Pizzuto
L. Di Pace
M.T. Porfiri
W. Gulden, V. Massout, S. Ciattaglia
R. Lässer, Y. Poitevin, G. Dell’Orco
(EFDA, Garching, Germany)
(EFDA, Garching, Germany)
P. Garin, J. Elbez-Uzan
J.F. Salavy, C. Girard
L. Rodriguez
L. Boccaccini
(CEA, Cadarache, France)
(CEA, Cadarache, France)
(EFDA, Barcelona, Spain)
(FZK, Karlsruhe, Germany)
J.P. Girard, M. Iseli, N. Taylor
Yican Wu
Mikio Enoeda
Dong Won Lee
Shishir Deshpande
Pavel Chaika
B. Merrill, L. Cadwallader
(ITER, Cadarache, France)
(IPP, China)
(Jaea, Japan)
(Kaeri, Korea)
(IPR, India)
(Sintez, Russia)
(INL, USA)
ENEA FPN FUSTEC Secretarial Staff
Authors:
T. Pinna
Archive
(ENEA, FUS, Frascati, Italy)
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EXECUTIVE SUMMARY
Objective of the report is to document the Failure Mode and Effect Analysis (FMEA)
performed for the European Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM)
to be installed in ITER.
The following sub-systems have been analysed by this study: TBM, TBM port plug, interspace and port cell equipment, helium coolant system, coolant purification system, coolant
pressure control system and tritium extraction system. The present study is focused on the
PI-TBM (Plant Integration TBM) module, which will operate in the last period of the high
duty cycle D-T phase.
On the base of design information reported on HCPB design description document, the set of
the most important components for safety analyses has been identified. For each of them, all
the possible failure modes that could occur during the burning and dwell operating phases
have been evaluated pointing out failure causes and possible actions to prevent the failure,
consequences and actions to prevent and mitigate the consequences, Postulated Initiating
Events (PIE) in which the safety relevant elementary failures are grouped.
The Burning and Dwell operating phases, the so called “Normal Operation”, have been
considered in identifying possible elementary failures and related consequences.
The total number of PIEs pointed out by assessing elementary failures related to the different
components of HCPB systems is 21. Accident sequences arising from each PIE have been
qualitatively defined. Deterministic analysis will have to demonstrate the plant capacity in
mitigating and, in every case, in withstanding accident consequences, arising from the overall
set of PIEs, below fixed safety limits.
Four out of the 21 PIEs were already identified by the FMEA on other ITER systems and
already documented in [GSSR]. The other seventeen PIEs are new ones and mainly refer to
typical faults in test blanket module systems. Six out of these seventeen events have been
highlighted as the ones more relevant to be studied with deterministic assessments. They are:
• FB1
(Loss of flow in a TBM cooling circuit because of circulator/pump seizure),
• LBB1 (Loss of TBM cooling circuit inside breeder blanket box: Rupture of a sealing
weld),
• LBO3 (LOCA Out-VV because of rupture of tubes in a primary TBM-HCS HX),
• LBP1 (LOCA Out-VV because of rupture of a TBM cooling circuit pipe inside Port Cell),
• LBV1 (Loss of TBM cooling circuit inside VV: Rupture of TBM-FSW),
• TBP2 (Small rupture from "TBM - Tritium Extraction System" process line inside Port
Cell).
All elementary failures not inducing safety relevant consequences have been classified in a
PIE named N/S (Not Safety relevant). Even if such failures are not important from a safety
point of view, they will be important on defining plant operability and maintenance strategy,
as well as they will be useful in evaluating worker safety.
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CONTENTS
EXECUTIVE SUMMARY........................................................................................................ 4
ACRONYMS ............................................................................................................................. 6
1
INTRODUCTION ............................................................................................................... 7
2
HCPB SYSTEM DESCRIPTION ....................................................................................... 7
3
OPERATING CONDITIONS ........................................................................................... 11
4
FAILURE MODE AND EFFECT ANALYSIS (FMEA) ................................................. 12
5
POSTULATED INITIATING EVENTS .......................................................................... 13
6
FB1
Loss of flow in a TBM cooling circuit because of circulator/pump seizure................................ 14
FB2
Partial flow blockage in a TBM cooling circuit because filter clogging ..................................... 16
HB1
Loss of heat sink in TBM cooling circuit .................................................................................... 16
LBB1
Loss of TBM cooling circuit inside breeder blanket box: Rupture of a sealing weld ................. 17
LBB2
Loss of TBM cooling circuit inside breeder blanket box: Leak of a sealing weld ...................... 18
LBO1
LOCA Out-VV because large rupture of TBM cooling circuit pipe inside TWCS Room.......... 18
LBO2
LOCA Out-VV because small rupture of TBM cooling circuit pipe inside TWCS Room ......... 20
LBO3
LOCA Out-VV because of rupture of tubes in a primary TBM-HCS HX .................................. 20
LBP1
LOCA Out-VV because of rupture of a TBM cooling circuit pipe inside Port Cell ................... 22
LBP2
LOCA Out-VV because small rupture of TBM cooling circuit pipe inside Port Cell................. 24
LBV1
Loss of TBM cooling circuit inside VV: Rupture of TBM-FSW................................................ 25
LBV2
Loss of TBM cooling circuit inside VV: Leak from TBM-FSW ................................................ 26
LFP2
LOCA Out-VV because small rupture of PFW/BLK cooling circuit pipe inside Port Cell ........ 27
LFV2
Small PFW/BLK in vessel LOCA. Equivalent break size: a few cm2 ........................................ 27
LVP2
Small rupture of VV cooling circuit pipe inside Port Cell........................................................... 28
LVV2
Small rupture in the internal VV shell - equivalent break size: a few cm2 ................................. 28
TBP2
Small rupture from “TBM - Tritium Extraction System” process line inside Port Cell .............. 29
TBL2
Small rupture from "TBM - Tritium Extraction System" process line inside Glove Box
containment ................................................................................................................................. 30
VBG1
Loss of vacuum in VV: break inside the VV of TBM purge gas system .................................... 30
VBG2
Loss of vacuum in VV: leak inside VV from TBM purge gas system ........................................ 31
VVA2
Ingress of air in the VV - small leakage ...................................................................................... 31
CONCLUSIONS ............................................................................................................... 33
REFERENCES......................................................................................................................... 34
Appendix A
List of components treated by the FMEA and related Figures
Appendix B
FMEA Table for EU HCPB TBM
Appendix C
PIEs related to failures on HCPB TBM systems with related elementary
contributors
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ACRONYMS
ACPs
ALARA
BPM
CPS
CV
DAC
DD
DT
ED
EFDA
EXPV
FMEA
FMS
FSW
FW
F/T
GB
HC
HCLL
HCPB
HCS
HIP
HP
HTS
HVAC
HX
I&C
IPC
IPCE
ITER
LiPb
N/S
ORE
PC
PCS
PFC
PIE
PP
PS
RadP_TES
RadP_VV
RH
TBM
TBS
TES
VV
VVPSS
WE
Activation Corrosion Products
As Low As Reasonable Achievable
Back Plate/Manifold
Coolant Purification System
Cryostat Volume
Derived Air Concentration
Deuterium - Deuterium
Deuterium Tritium
Energy Dumping
European Fusion Development Agreement
Expansion Volume
Failure Mode and Effect Analysis
Fuel Management System
First Side Wall
First Wall
Feed-Through
Glove Box
Hot Cell
Helium Cooled Lithium Lead
Helium Cooled Pebble Bed
Helium Cooling System
Hot Isostatic Pressing
Health Physics
Heat Transfer System
Heating and Ventilation Air Conditioning
Heat Exchanger
Instrumentation and Control
Inter-space and Port Cell
Inter-space and Port Cell Equipment
International Tokamak Fusion Reactor
Lithium Lead
Not Safety Relevant
Occupational Radiation Exposure
Port Cell
Pressure Control System
Plasma Facing Component
Postulated Initiating Event
Port Plug
Power Supply
Radioactive Products contained in Tritium Extraction System (purge gas), e.g.: Tritium and
activated products
Radioactive Products contained in Vacuum Vessel, e.g.: Tritium and activated dusts
Remote Handling
Test Blanket Module
Test Blanket System
Tritium Extraction System
Vacuum Vessel
Vacuum Vessel Pressure Suppression System
Work Effort
1
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INTRODUCTION
The report addresses the identification of postulated initiating events (i.e.: off-normal events
which may result in hazardous consequences) arising from European Helium Cooled Pebble
Bed (HCPB) Test Blanket Module (TBM) systems.
A systematic method, the Failure Mode and Effect Analysis (FMEA), has been used to ensure
that a full range of potential faults and off-normal conditions have been considered.
Several documents have been taken as reference in defining design solutions:
2
•
European Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) Detailed
Description Document (DDD), December 2005 [DDD HCPB]
•
Integration of TBM Helium coolant system in ITER, December 2005 [NEUBER]
•
Meeting presentations on “The HCPB Test Blanket Module for ITER” made till
September 2006.
HCPB SYSTEM DESCRIPTION
The Test Blanket System (TBS) is an experimental device for the testing in a real fusion
environment DEMO-relevant blanket concepts before the construction of a DEMO reactor.
In the following a short description of components/sub-systems, extracted from [DDD
HCPB]. The detailed list of components treated by the FMEA is reported in Appendix A, with
assigned labels, description, useful comments and Figures.
The helium cooled pebble bed (HCPB) ceramic blanket is one of two blanket concepts chosen
in the Frame of the European Blanket Programme as a DEMO relevant Blanket. Distinguish
features of this concept are the use of the Ceramic Breeder and the Beryllium Multiplier in
form of flat pebble beds, which are separated and cooled by cooling/stiffening plates. The
coolant helium at high pressure (8 MPa) and high temperature flows in the first wall and the
breeding zone in small channels, while the beds self are purged by a low pressure Helium
flow. This independent purge flow removes the Tritium produced in the beds, carries it to a
Tritium Extraction System and keeps low the Tritium partial pressure at the interface with the
coolant channels reducing the permeation flow to the main coolant system. Hence, permeation
barriers (coatings) are not necessary between the two loops.
This concept has seen steady development over the past years and adapted to different fusion
reactor concepts or to different structural materials (EUROFER, ODS or SiCf/SiS).
The TBS is composed of the following elements and their components:
The Test Blanket Module (TBM). The test blanket module encompasses the function of the
first wall, breeding blanket, shield and structure. Its principal functions in ITER are, besides
serving as test module, to remove surface heat flux and energy from plasma during normal
and off-normal operational conditions, and to contribute to the shielding to the vacuum vessel
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and super-conducting coils. It will be inserted in an Equatorial Port of ITER inside the
vacuum vessel in front of the plasma.
The TBM Port Plug (PP). The PP contains the TBMs and provides thermal and neutronic
insulation from the ITER basic machine. It allows the TBM replacement through the port
itself. The front part (called “frame”) has also FW functions. The mechanical interface with
the ITER machine will be provided by the PP rear part (“flange”); this flange is supported by
the VV port extension. The PP provide also neutron shielding; a thick water cooled “shield” is
placed behind the TBM. The pipes coming from the TBMs and crossing the PP up to the
boundary with the inter-space are considered part of the PP.
The Interspace and Port Cell Equipment (IPCE). The Piping and loop components
belonging to the main helium coolant and that connect the port plug to the interface to the
TCWS (shaft wall).
The Helium Coolant System (HCS). This system shall provide the He coolant at the
characteristic of pressure, temperature and mass flow required by the TBM for the testing and
for the extraction of the heat produced. The components (compressor, heat exchanger, etc.)
and the piping allocated in the TCWS vault are part of this system.
The Tritium Extraction System (TES). Function of the TES is to remove the Tritium
produced in the TBM pebble beds and control the gas composition of the low pressure purge
flow. This system is connected to the TBM and its allocation is anticipated in the Tritium
Building.
The Coolant Purification System (CPS). Function of the CPS is to remove the Tritium that
can permeate in the coolant and other impurities, and control the gas composition in the HCS
(partial pressure of H2 and H2O). This system is connected to the HCS and its allocation is
anticipated in the TCWS.
Other systems: measurement or Helium conditioning Systems, instrumentation control and
management. These systems will be allocated in front of the VV Port and almost integrated in
the IPCE.
Three of the equatorial ports (2, 16 and 18) are dedicated for blanket test modules. The EU
HCPB TBM is supposed to be allocated in Port 16, sharing the place with another blanket
with similar characteristic (Helium cooled Solid breeder blanket).
For the first 10 years of operation the ITER time-schedule envisages four plasma phases, HH, D-D, low and high duty cycle D-T with related operating conditions. Because of the
differences between the ITER loading conditions and those expected in DEMO, the option of
testing several 'act alike' TBMs is selected, which will allow to adapt each module and
relevant instrumentation to the ITER parameters in each phase. Moreover, this process will
allow to gradually validate the HCLL blanket concept, technologies and design tools while
having the minimum impact on ITER safety and availability.
It is foreseen to test 4 types of EU HCPB TBM corresponding to different ITER phases:
•
EM-TBM: Electromagnetic module (plasma H-H phase to investigate the response of
the structure to electromagnetic transients and to test operational function);
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•
NT-TBM: Neutron and Tritium module (plasma D-D and first period of the D-T low
cycle phases for investigation of neutronic responses and Tritium
generation/extraction);
•
TM-TBM: Thermo-Mechanic module (for investigation of the pebble bed behaviour
at relevant temperatures for the DEMO during the low duty D-T plasma phase);
•
PI-TBM: Plant Integration module (last period of the high duty cycle D-T phase to
demonstrate operational behaviour of the blanket component in the heat extraction and
tritium management).
The present study is focused on the PI-TBM module because the operating conditions are the
most relevant from a safety point of view.
The HCPB-TBM should be located in the upper part of the port plug frame; the foreseen
place has dimensions of 780 mm in poloidal direction, 1310 mm in toroidal direction and 800
mm (maximum) in radial direction. Taking into account 20 mm gap between TBMs and
Frame the maximum dimensions of each TBM’s is 740 mm high and 1270 mm wide.
The first wall of the TBM is planar, without curvature, recessed 20 mm (minimum) with
respect to the frame first wall. The TBM first wall is protected by a Beryllium layer of 2 mm.
The radial dimension of the TBM is circa 700 mm including the mechanical attachment.
A test module is constituted by the following sub-components:
• First-Side wall (FSW);
• Caps
• Grid
• Breeder Unit (BU);
• Back Plate/Manifold (BPM);
• PP Interface System (PP-IS).
The FSW is U shaped and has cooling channels in radial - toroidal direction; to keep in the
testing the same mechanical features of the DEMO component i.e. the possibility to withstand
a 8 MPa over-pressurisation of the box, the dimensioning of the FSW (thickness and channels
dimension) is in the range of the dimensions used in DEMO FSW. However, due to the
particular conditions in ITER (shorter module of 1.2 m instead of 2 m, and relatively lower
neutron wall load) this would cause too low velocity of He in the channels and a reduced heat
transfer capability at the plasma side. Hence, a double sweep is used to increase of 3 times the
channel length allowing the increase of the helium velocity in the channels without changing
the DEMO-relevant geometry of the channel selves. This solution has as drawback an
increase of pressure drops in the fist wall up to 0.3 MPa.
The TBM box is closed at the top and bottom with caps about 40 mm thick. They are
equipped with cooling channels similar to the first wall; the cooling channels have different
length in order to adjust the cooling capability to the reduction of the specific power released.
The cap is made from two plates of equal thickness, being combined by HIP. The cooling
channels have holes in the internal surface of the Cap; these holes are located in two rows
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(like in the FSW) corresponding to the inlet and outlet manifolds. The caps will be welded to
the FSW forming the upper and the lower faces of the TBM box.
The stiffening grid allows the modular DEMO blanket to enforcing the box against an
accidental internal over-pressurisation of 8 MPa; this feature is kept also in the TBM design.
The stiffening grid plates necessitate to be actively cooled; coolant Helium flowing in internal
meandering channels will remove the heat generated in the steel plates self but also coming
from the breeding region. The grid is welded to the FWS-Caps assembly assuring the
necessary mechanical strength against the postulated accidental events of box full
pressurisation. The coolant channels have the ends on the rear part, in structures called legs.
The legs have different lengths to reach the corresponding inlet and outlet manifolds. The legs
will be welded to the BPM, assuring Helium tightness between the low pressure breeding
zone and the high pressure manifold region, and mechanical connection against box
pressurisation
The breeder unit for the DEMO HCPB consists of four canisters and a supporting plate. The
canisters are filled with ceramic breeder (Li4SiO4 or Li2TiO3) pebbles of diameters in the
range 0.2-0.6 mm (poly-disperse bed) and 0.8-1.0 mm (mono-sized) mm, respectively. The
space between the canister outside surface and the stiffening grid is filled with Beryllium
pebbles having a diameter of about 1 mm; the estimated packing factor for the various beds
will be in the order of 63%. The canisters are made of two cooling plate cooled with internal
channels; they are closed by a wrap, that connects the two cooling plates. The canisters are
closed at the sides to separate the Helium purge flow in the ceramic and in beryllium. The
breeding canisters are welded to the breeding unit back plate which also incorporates the
manifolds for supply and collection of the coolant. For Tritium removal also a purge gas
circuit is incorporated into the BU.
The back plate closes the TBM box from the rear side, provides the support for the
mechanical attachment at the interface with the ITER Port Plug and forms a high pressure
manifold system for the Helium feeding the different part of the TBM (FW, Caps, Grid and
Breeder Units). The back plate is made by two thick plates (about 40 mm) connected by ribs
(called also ships). The place between these two plates is divided by thin plate (about 5mm)
and by the rib system in several chambers to accommodate the manifolds necessary for the
coolant distribution. The back plate supports also the manifolds for the low pressure purge
system. The purge gas is led to the purge gas manifold, in radial direction in front of the
bottom plate of manifold 3. From there individual tubes guide the flow to the BU back plates
and from there through the beds. From the beds the purge gas is collected in the purge gas
collector and from there via a pipe led outside of the TBM.
The PP interface system is composed by several sub-systems that assure the interface with the
ITER Port Plug or with RH equipment. They are mechanical attachment, pipe connections,
grounding and gripping system.
The He cooling system includes the primary helium heat transport loop with all components
and the secondary heat removal loop. The secondary water loop is part of the ITER tokamak
cooling water system (TCWS). The cooling system is housed in the TCWS vault at the CVCS
level, approximately 40 m away from the TBM.
The TBM will be designed to operate at elevated temperatures relative to the shield blanket
systems. This will allow the test blanket to demonstrate the tritium breeding capability and
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generation of high grade heat. The maximum temperatures for the coolant helium will be 500
°C, structural material up to 550 °C, solid breeder material up to 920 °C and Be 650 °C.
To get high temperature in BUs and keep low temperature in the FW, a partial bypass is
foreseen in the He flowing according the flow scheme represented in the following figure 2-1.
Figure 2-1 – Scheme of He flowing in HCPB TBM
3
OPERATING CONDITIONS
The Burning and Dwell operating phases, the so called “Normal Operation”, have been
considered in identifying possible elementary failures and related consequences.
4
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FAILURE MODE AND EFFECT ANALYSIS (FMEA)
The components of the EU HCPB TBM systems have been analysed with the FMEA
methodology. For each one of them, the possible failure modes that could occur in the
operating phases have been evaluated. For each of them, all the possible failure modes that
could occur during the burning and dwell operating phases have been evaluated pointing out
failure causes and possible actions to prevent the failure, consequences and actions to prevent
and mitigate the consequences, Postulated Initiating Events (PIE) in which the safety relevant
elementary failures are grouped.
From a safety point of view, the PIEs are the most representative accident initiators, in terms
of radiological consequences, between a set of elementary events challenging the plant in
similar way and, producing equivalent fault plant conditions. By this method each defined
PIE is characterized by:
•
•
a set of elementary accident initiators grouped under the PIE;
a representative event, which is one of the contributors (generally, the one posing the
most severe challenging conditions).
The PIEs definition is useful to limit the set of accident initiators to be taken into account in
the deterministic transient analyses. In fact, they are representing the most challenging
conditions for the plant, guessing that consequences from PIEs are the most severe (upper
limit) of the ones that could concern all the elementary initiators grouped on them.
The detailed FMEA table is reported in Appendix B.
5
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POSTULATED INITIATING EVENTS
The total list of PIEs recognized by the FMEA on European HCPB Test Blanket Module
systems is reported in the following Table 5-1.
Furthermore it has been reported in Appendix C the list of identified PIEs and the related
elementary failures that contribute to each PIE. In the tables, Operating phase, PIE code, code
and description of components whose failure will induce the PIE and component failure mode
are detailed.
Table 5-1 – Total list of PIEs identified by the FMEA on TBM-HCPB model
- PIEs FB1
FB2
HB1
LBB1
LBB2
LBO1
TBP2
VBG1
VBG2
VVA2
Description
Loss of flow in a TBM cooling circuit because of circulator/pump seizure
Partial flow blockage in a TBM cooling circuit because filter clogging
Loss of heat sink in TBM cooling circuit
Loss of TBM cooling circuit inside breeder blanket box: Rupture of a sealing weld
Loss of TBM cooling circuit inside breeder blanket box: Leak of a sealing weld
LOCA Out-VV because large rupture of TBM cooling circuit pipe inside TWCS
Room
LOCA Out-VV because small rupture of TBM cooling circuit pipe inside TWCS
Room
LOCA Out-VV because of rupture of tubes in a primary TBM-HCS HX
LOCA Out-VV because of rupture of a TBM cooling circuit pipe inside Port Cell
LOCA Out-VV because small rupture of TBM cooling circuit pipe inside Port Cell
Loss of TBM cooling circuit inside VV: Rupture of TBM-FSW
Loss of TBM cooling circuit inside VV: Leak from TBM-FSW
LOCA Out-VV because small rupture of PFW/BLK cooling circuit pipe inside
Port Cell
Small PFW/BLK in vessel LOCA. Equivalent break size: a few cm2
Small rupture of VV cooling circuit pipe inside Port Cell
Small rupture in the internal VV shell - equivalent break size: a few cm2
Leak of TBM - Tritium Extraction System process line inside Glove Box
containment
Leak of TBM - Tritium Extraction System process line inside Port Cell
Loss of vacuum in VV: break inside the VV of TBM purge gas system
Loss of vacuum in VV: leak inside VV from TBM purge gas system
Ingress of air in the VV - small leakage
N/S
Not Safety Relevant
LBO2
LBO3
LBP1
LBP2
LBV1
LBV2
LFP2
LFV2
LVP2
LVV2
TBL2
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The PIEs have been discussed, as it is described in the following, to qualitatively define
possible accident evolutions.
It’s important to note that the discussions on PIEs focuses on consequences related to public
safety. But, it has to be considered that any failure that could occur in the TBM systems could
have significant consequences in terms of occupational radiation exposure, both to perform
recovery actions and to perform decontamination, if it needs. Dedicated studies have to be
done on the matter and detailed procedures, in an ALARA context, have to be defined to
perform the different recovery and/or maintenance activities.
The PIE category N/S collects all the elementary events estimated as not leading to any public
safety relevant disturbance.
FB1
The severe loss of flow in the TBM cooling circuit could be determined by a seizure of the
circulator or malfunctions in some valves located in the HCS circuit. The reference event
selected to represent the PIE is the circulator seizure.
The following chain of consequences could follow the initiator:
Loss of He coolant flow
Increase of temperature in HCS loop
HCS loop over-pressurization
Pressure relief towards PCS
Increase of temperature in TBM box
Swelling of Ceramic Breeder Pebbles
Swelling of Be pebbles
Over thermo-mechanical stress on BU, Grid, Caps and FSW structures
Break in BUs and TBM structures if plasma is not shutdown
Loss of He coolant into VV
Plasma disruption
VV pressurisation
Pressure relief towards VVPSS
Release of radioactive products contained in VV (tritium & dusts) into VVPSS
Possible local VV pressurization over design limits in case of particular dynamic effects
or fault in VVPSS devices opening. In such a case, the following aggravating failures
could follow:
-
Possible loss of leak tightness in feedthroughs or windows of VV
-
Release into Port Cell of radioactive products contained in VV (tritium & dusts)
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Loss of purge gas into VV
Possible pressurization of purge gas system (TES) up to VV pressure. In such a case, the
aggravating failures related to the possible loss of leak tightness in purge gas system
should be prevented because TES is designed to withstand 2 MPa (i.e.: VVPSS should be
able to keep lower values inside the VV)
Loss of Be pebbles into VV due to dynamic effects (e.g. VV suction, He flowing) caused
by the FW rupture
Possible rupture in other water cooled PFCs due to disruption. In such a case, the
following aggravating failures could follow:
-
VV over-pressurization due to the combined effects of He and steam
-
Reaction between steam lost from PFCs and Be [Be pebbles inside the vessel (low T)
& Be pebbles remained in the TBM box (high T) & Be armour of PFCs (low T)].
About these reactions it is worthwhile to remark that pebbles of Be released in VV
should be cooled down by the water entering the VV. Consequently, related Bewater reaction should have milder effects. But, on the other hand, due to the
discharging of pebbles from the TBM box, more free space is available for the steam
to enter the TBM box. Steam that could better reacts with pebbles remained in the
box
-
H2 production
-
Risk of H2 explosion in case air gets in touch with H2
About mitigating actions to prevent environmental release it has to be considered at first:
•
Monitoring of TBM coolant inlet flow-rate and temperature
•
Plasma shutdown
•
Periodic testing & maintenance of VVPSS devices
•
Design VVPSS to treat over pressurization generated by He gas
•
Design VVPSS to treat over pressurization generated by mixture of He gas and steam
•
Provide TES with dedicated devices to avoid pressurization of the circuit by gases
coming from TBM box side (He coolant and/or steam from VV).
•
Isolation of broken circuits to reduce the coolant released in VV
•
Increase cooling capability of effective circuits in order to quickly reduce temperature
of PFCs and VV structures
This PIE could have similar consequences then the ones expected for the LBV1 described
below. However in the case of FB1 initiator Be pebbles get higher temperature before the
module in-vessel breaks. On the other hand, the detection of the loss of flow should be quite
rapid and sufficient time should be available to intervene shutting down the plasma. Anyway,
FB1 followed by TBM in-vessel break because contemporaneous failure to shutdown the
plasma can be considered as one of the bounding accidents for the ITER TBM.
FB2
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The reduction of flow in a TBM cooling circuit could be determined by “Dust Filter –
Clogging” or “Recuperator/economizer - Internal rupture” or a failure in the Valve 1 (Fig. 17)
to control the mass flow through the HCS circuit. The first elementary failure has been
selected as represented event of the PIE.
Partial loss of He coolant flow into TBM box
Consequences as for the one described for the FB1 about “Possible rupture in other water
cooled PFCs due to disruption” could follow.
Same preventive/corrective actions of the ones listed for the FB1 PIE can be considered for
the FB2 PIE.
FB1 is most significant, with respect to this PIE, in terms of containments challenging and
risks for releases into plant areas and environment.
HB1
The loss of heat sink in TBM cooling circuit could be determined by several faults in the
secondary loop of HCS. In this assessment only the inlet leg to the HX has been assessed. So
only an elementary failure has been identified. It is the “Valve 2 (Fig. 17) used to control the
secondary circuit of the cooler to have influence on the circulator inlet temperature - fail to
operate sticking completely closed”.
Loss of Heat Sink to HCS
Increase of temperature in HCS loop
HCS loop over-pressurization
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Consequences as for the one described for the FB1 about “Possible rupture in other water
cooled PFCs due to disruption” could follow.
About mitigating actions to prevent environmental release it has to be considered at first:
•
Monitoring of secondary loop flow rate
•
Monitoring of TBM coolant inlet flow rate and temperature
•
Plasma shutdown
•
•
•
•
coming from TBM box side (He coolant and/or steam)
•
•
FB1 is most significant, with respect to this PIE, in terms of HCS pressurization,
containments challenging and risks for releases into plant areas and environment.
LBB1
Loss of TBM cooling circuit inside breeder blanket box: Rupture of a sealing
weld
Several rupture of welds sealing supporting plates and plate manifolds could determine
ingress of helium coolant at 8 MPa into TBM box.
Loss of He coolant into the TBM box
Pressurization of TBM box to He coolant pressure
Pressurization of TES if it is not promptly isolated
Possible loss of leak tightness in purge gas system
Release of Tritium from TES and TBM to Port Cell and/or to Glove Box according the
leak location in the TES circuit.
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The box is designed to withstand 8 MPa absolute, but overstress due to thermal cycle could
determine consequential leaks into VV if the plasma is not shutdown and safety conditions set
up. The actions to be taken could be:
•
Monitoring of TBM box pressure
•
Isolation of TES to prevent over-pressurization
•
Stop ITER operations
•
Perform TBM maintenance or
•
set TBM system in a way to continue ITER pulses at least until next plant shutdown
(i.e.: interruption of TBM experimental campaign);
The following measures could be adopted according the needs for the latter action: closing of
"IPCE-HCS-V3" valve on bypass line (Fig. 17), reduction of He coolant pressure, partial
isolation of TES (bypass tritium extraction components but keep effective cooling of gas),
etc."
LBB2
Loss of TBM cooling circuit inside breeder blanket box: Leak of a sealing weld
Leaks from welds sealing supporting plates and plate manifolds could determine small ingress
of helium coolant at 8 MPa into TBM box. Also several malfunctions, such as creation of
empty spaces inside pebble beds or grid deformation or failure to operate of the TBM bypass
valve could generate over thermo-mechanical stress and consequential leaks if the plasma is
not shutdown.
Same consequences then the ones described for the LBB1 PIE could be expected even if with
more relaxed transients. Also mitigating actions could be the same.
LBB1 is most significant, with respect to this PIE, in terms of containments challenging and
LBO1 LOCA Out-VV because large rupture of TBM cooling circuit pipe inside TWCS
Room
A large LOCA out-vessel from the TBM HCS could be determined by a significant rupture in
the cooling circuit from components located in the HCS room or in the piping running from
the Port Cell to the HCS room (i.e.: service shaft and TWCS Room). The representative event
here selected has been the break of a cooling pipe inside the TWCS Room (HCS zone).
Loss of He coolant into Vault
Pressurization of Vault
Release of Tritium contained in He coolant into Vault
Emptying of the TBM cooling loop and loss of heat removal capability
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Overheating of TBM if the plasma is not promptly shutdown
Swelling of Ceramic Breeder and Be pebbles
Ingress of air in TBM box cooling channels when the pressure in cooling circuit gets
room pressure
Be-air and Be-water (moisture contained in air) reactions if coolant channels inside the
box lost their integrity because thermo-mechanical stress, particularly, if the plasma is
not shutdown. In such a case, the following aggravating failures could follow:
-
H2 production
-
Possible H2 explosion inside the box
Possible break of TBM box
Ingress of He (i.e.: some coolant not yet discharged from the loop and purge gas) and air
(from the external break) into VV
Plasma disruption if it has not been actively or passively (plasma poisoning due to
armour material evaporation) shutdown
VV pressurisation
Opening of bleed lines towards VVPSS when VV pressure gets 80 kPa and opening of
lines to drain tank when p>110kPa
Release of radioactive products contained in VV (tritium & dusts) to VVPSS
Release of radioactive products contained in VV (tritium & dusts) to TWCS Room if VV
pressure overcomes room pressure
by the FW rupture. In this case, it is also worthwhile to remark that the loosing of pebbles
inside the VV makes more complicated recovery actions inside the VV to clean vacuum
chamber before restart. Consequences that could reduce plant availability
Aggravating consequences could occur in case of rupture in other water cooled PFCs due
to disruption
Mitigating actions to prevent environmental release and/or to limit damage could be:
•
Prompt shutdown of the plasma to avoid aggravating in-vessel failures. The shutdown
of the plasma could be triggered by control of HCS parameters and by monitoring of
amount of He contained in Vault atmosphere
•
Isolation of broken circuits to reduce the coolant released into the Vault
•
Isolation of HVAC
•
Vault atmosphere detritiation by Vent Detritiation System.
Deterministic assessment has to investigate on timing available to safely prevent propagation
of faults in in-vessel components and, in case they occur, what consequences could be
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expected in terms of mobilization of radioactive products into the TWCS Room and release to
the environment.
LBO2 LOCA Out-VV because small rupture of TBM cooling circuit pipe inside
TWCS Room
Several leaks from the TBM HCS and its auxiliary circuits, such as PCS and CPS are grouped
in the LBO2 PIE. A small rupture in a cooling pipe located in the TWCS room (HCS zone)
has been selected as representative event.
Loss of He coolant into Service Shaft and/or Vault
Release of Tritium contained in He coolant into Service Shaft and/or Vault
In case of HCS leak there’s enough time to detect the initiator and to shutdown the plasma.
Therefore, aggravating failures in in-vessel TBM components are not credible.
About mitigating actions to prevent environmental release and worker exposure it has to be
considered:
•
Monitoring of amount of He contained in Service Shaft and Vault atmosphere in order
to promptly detect leaks;
•
Isolation of broken circuits to reduce the coolant released into Service Shaft and/or
Vault;
•
Isolation of HVAC;
•
Vault atmosphere detritiation;
LBO1 is most significant, with respect to the LBO2 PIE, in terms of containments challenging
and risks for releases into plant areas and environment.
LBO3 LOCA Out-VV because of rupture of tubes in a primary TBM-HCS HX
Inner pipe breaks in heat exchanger of HCS or cooler of CPS are grouped in the LBO3 PIE. A
multiple pipe rupture in the HCS-HX has been selected as representative event.
Loss of He coolant into secondary cooling circuit
Release of Tritium contained in He coolant into secondary cooling circuit
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Ingress of water in TBM box cooling channels when the pressure in cooling circuit gets
secondary cooling loop pressure
Be-water reactions if coolant channels inside the box lost their integrity because thermomechanical stress, particularly, if the plasma is not shutdown. In such a case, the
-
H2 production
-
Ingress of He (i.e.: some coolant not yet discharged from the loop and purge gas) and
water (from the external break in the HX) into VV
VV pressurisation
Release of radioactive products contained in VV (tritium & dusts) to secondary loop if
VV pressure overcomes secondary cooling loop pressure
by the FW rupture
to disruption
About mitigating actions to prevent environmental release it has to be considered:
•
Monitoring of secondary loop parameters (flow rate, temperature and pressure)
•
Monitoring of HCS parameters (flow rate, temperature and pressure)
•
Plasma shutdown
•
Isolation of secondary loop
•
•
•
•
•
•
•
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Maintenance of HX (pipe plugging)
The emptying of the HCS loop for the LBO3 PIE should be slower than the emptying of the
HCS loop for the LBO1 and LBP1 PIEs because the balance of pressures and constrains
between HCS and the volume where the helium is discharged. So that, the challenging of the
TBM integrity should be higher in the LBO1 and LBP1 cases than for the LBO3 cases.
Nevertheless, the LBO3 should be investigated the same by deterministic assessment in order
to evaluate chance to get conditions for water of secondary loop to get in touch with Be
pebbles inside the TBM box.
LBP1
LOCA Out-VV because of rupture of a TBM cooling circuit pipe inside Port
Cell
A significant rupture in the TBM cooling circuit from components located in the Inter-space
and Port Cell determines a large LOCA out-vessel similar to the one described in LBO1 PIE.
Practically, the effects on TBM box are quite similar, but the He discharging and,
consequentially, the radioactive release that potentially could occur are in a different
confining zone of the plant. The Port Cell, actually, has the function of secondary
confinement as the Vault but the volume available for the expansion of gas relieved is
reduced. Therefore, challenging of containment structures has to be investigated, as well as
timing available to intervene in the isolation of the HVAC and risks to relieve radioactive
products into the building without confinement function. Those are the reasons of the creation
of different grouping in different PIEs for different ex-vessel LOCA.
The representative event selected for the LBP1 PIE is the break of a cooling pipe inside the
Port Cell.
Loss of He coolant into Port Cell
Pressurization of Port Cell
Release of Tritium contained in He coolant into Port Cell
Possible loss of Port Cell confinement towards Service Shaft and/or Gallery
Ingress of air in TBM box cooling channels when the pressure in cooling circuit gets Port
Cell pressure
Be-air and Be-water (moisture contained in air) reactions if coolant channels inside the
box lost their integrity because thermo-mechanical stress, particularly, if the plasma is
not shutdown. In such a case, the following aggravating failures could follow:
-
H2 production
-
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Ingress of He (i.e.: some coolant not yet discharged from the loop and purge gas) and air
(from the external break) into VV
VV pressurisation
Release of radioactive products contained in VV (tritium & dusts) to Port Cell if VV
pressure overcomes Port Cell pressure
by the FW rupture. In this case, it is also worthwhile to remark that the loosing of pebbles
inside the VV makes more complicated recovery actions inside the VV to clean vacuum
chamber before restart. Consequences that could reduce plant availability
to disruption
Mitigating actions to prevent environmental release and/or to limit damage could be:
•
Prompt shutdown of the plasma to avoid aggravating in-vessel failures. The shutdown
of the plasma could be triggered by control of HCS parameters and by monitoring of
amount of He contained in Port Cell atmosphere
•
Isolation of broken circuits to reduce the coolant released into the Port Cell;
•
Isolation of HVAC;
•
Activation of Vent Detritiation System.
Deterministic assessment has to investigate on timing available to safely prevent propagation
of faults in in-vessel components and, in case they occur, what consequences could be
expected in terms of mobilization of radioactive products into the Port Cell and release to the
environment.
The LBP1 could be more severe then the LBO1 in terms of public safety because the faster
transient that could determine over-pressurization of the room where the LOCA occurs and
the challenging to the integrity of the containment systems.
Also, in terms of worker safety the LBP1 could have more severe consequences despite the
extension of contamination that could be caused with the LBO1 PIE with respect to the ones
caused by the LBP1 initiator. Precisely, the procedure to be applied in case of LOCA in the
Vault or in a Port Cell should be:
1. Isolation of HVAC;
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2. Activation of coolers to cool down gases and/or steam released in the room in order to
blow down the over-pressure;
3. Activation of the VDS when the room pressure does not any more exceed atmospheric
pressure.
During time of isolation the tritium released into the room will interact with room and
equipment surfaces and will be adsorbed by those surfaces. The longer the time to start
ventilation, the higher is the tritium that permeates into the structures and the longer is the
time required to decontaminate the surfaces. Moreover, when the tritium gas interacts with
room and equipment surfaces, an isotopic exchange process takes place between the tritium
gas molecules and water vapour molecules on the surfaces. Accordingly, when the tritium is
desorbed from those surfaces, it is mainly in the more hazardous HTO form. Therefore, the
higher the amount of tritium adsorbed by the surfaces, the higher is the radiological hazardous
determined by the release.
Qualitatively comparing the two PIEs, it is expected that the over-pressurization of the room
where the release occurs and, consequentially, the amount of tritium that will be adsorbed by
the structure surfaces will be higher in the case of LBP1 then in the case of LBO1.
Furthermore, being the section of the LBP1 ex-vessel break significantly nearer to the invessel components then the section of the LBO1 break, the amount of radioactive products
that can be mobilized from TBM box and from VV to the room is higher in the first case with
respect to the latter case.
LBP2
LOCA Out-VV because small rupture of TBM cooling circuit pipe inside Port
Cell
Several leaks from the TBM HCS components located in the inter-space and Port Cell are
grouped in the LBP2 PIE. A small rupture in a cooling pipe has been selected as
representative event.
Loss of He coolant into Port Cell
Slight pressurization of Port Cell
Release of Tritium contained in He coolant into Port Cell
In case of HCS leak there’s enough time to detect the initiator and to shutdown the plasma.
Therefore, aggravating failures in in-vessel TBM components are not credible.
considered:
•
Isolation of broken circuits to reduce the coolant released in Port Cell;
•
Isolation of HVAC;
•
Port Cell atmosphere detritiation;
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LBP1 is most significant, with respect to the LBP2 PIE, in terms of containments challenging
LBV1 Loss of TBM cooling circuit inside VV: Rupture of TBM-FSW
Several ruptures in the TBM structure (e.g.: First Wall, Caps, Plate Manifolds) could
determine a large in-vessel LOCA from TBM. A catastrophic rupture in the FSW that cause
the loss of integrity in both the containments of He coolant and He purge gas has been
selected as representative event.
Plasma disruption
VV pressurisation
Possible local VV pressurization over design limits in case of particular dynamic effects
or fault in VVPSS devices opening. In such a case, the following aggravating failures
could follow:
-
Possible loss of leak tightness in feedthroughs or windows of VV
-
Release into Port Cell of radioactive products contained in VV (tritium & dusts)
Possible pressurization of purge gas system (TES) up to VV pressure. In such a case, the
aggravating failures related to the possible loss of leak tightness in purge gas system
should be prevented because TES is designed to withstand 2 MPa (i.e.: VVPSS should be
able to keep lower values inside the VV)
by the FW rupture
Possible rupture in other water cooled PFCs due to disruption. In such a case, the
-
VV over-pressurization due to the combined effects of He and steam
-
Reaction between steam lost from PFCs and Be [Be pebbles inside the vessel (low T)
& Be pebbles remained in the TBM box (high T) & Be armour of PFCs (low T)].
About these reactions it is worthwhile to remark that pebbles of Be released in VV
should be cooled down by the water entering the VV. Consequently, related Bewater reaction should have milder effects. But, on the other hand, due to the
discharging of pebbles from the TBM box, more free space is available for the steam
to enter the TBM box. Steam that could better reacts with pebbles remained in the
box
-
H2 production
-
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About preventive and mitigating actions to prevent environmental release and worker
exposure it has to be considered:
•
•
•
•
•
•
LBV2 Loss of TBM cooling circuit inside VV: Leak from TBM-FSW
Several leaks from the TBM structure (e.g.: First Wall, Caps, Plate Manifolds) could
determine a small in-vessel release of He coolant from TBM. Besides these elementary
initiators, also the failure to operate on demand of the PCS and, precisely, of a valve in the
PCS circuit, is grouped in the LBV2 PIE. A small rupture in a weld sealing the FSW channels
has been selected as representative event.
Plasma disruption
VV pressurisation
Possible rupture in other water cooled PFCs due to disruption
VV over pressurization due to the combined effects of He and steam
Reaction between steam lost from PFCs and Be armour
H2 production
Aggravating failures in in-vessel TBM components are not credible.
considered:
•
•
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•
•
•
LBV1 is most significant, with respect to the LBV2 PIE, in terms of containments challenging
LFP2
Port Cell
This PIE should group all the failures that could occur in all Port Cells of ITER because small
rupture of piping of the PFW/BLK cooling circuit that passes through the Port Cell. In our
case the pipes could be the water cooling pipes (Inlet/Outlet) used to cool-down the frame and
shielding parts of the Port Plug.
Loss of PFW/BLK water coolant into Port Cell
Release of Tritium & ACPs contained in PFW/BLK loop into Port Cell
considered:
•
Isolation of broken circuits to reduce the coolant released in Port Cell
•
Port Cell water drainage and atmosphere detritiation
LFV2
Small PFW/BLK in vessel LOCA. Equivalent break size: a few cm2
Leaks from the TBM port plug frame and shield could determine a small in-vessel release of
water coolant from the PFW/BLK cooling circuit. This PIE has been already determined by
the FMEA on the PFW/BLK heat transfer system.
Loss of PFW/BLK water coolant into VV
Plasma disruption
VV pressurisation
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considered:
•
Isolation of broken circuits to reduce the coolant released into VV
This PIE has been already treated deterministically in [GSSR].
LVP2
Small rupture of VV cooling circuit pipe inside Port Cell
This PIE should group all the failures that could occur in all Port Cells of ITER because small
rupture of piping of the VV cooling circuit that passes through the Port Cell. In our case the
pipes could be the water cooling pipes (Inlet/Outlet) used to cool-down the rear part and
flange of the Port Plug.
Loss of VV water coolant into Port Cell
Release of Tritium & ACPs contained in VV loop into Port Cell
considered:
•
Isolation of broken circuits to reduce the coolant released in Port Cell
•
Port Cell water drainage and atmosphere detritiation
LVV2 Small rupture in the internal VV shell - equivalent break size: a few cm2
Leaks from the rear part of the TBM port plug and port plug flange to VV could determine a
small in-vessel release of water coolant from the VV cooling circuit. This PIE has been
already determined by the FMEA on the VV and on the VV heat transfer system.
Loss of VV water coolant into VV
Plasma disruption
VV pressurisation
considered:
•
Isolation of broken circuits to reduce the coolant released into VV
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TBP2
Small rupture from “TBM - Tritium Extraction System” process line inside
Port Cell
This PIE groups leaks from the TES circuit into the Port Cell. The leaks have been identified
by considering that no secondary containment exists around the process line. Really, the
design has not yet evaluated needs and advantages of such further boundary. Surely, it would
create a further protection against environmental release, but on the other hand it would
generate considerable complications for TBM ex-vessel component maintenance and
TBM/Port Plug replacement by RH. Therefore, the question has to be evaluated in the frame
of the ALARA process.
A small rupture in the TES piping located in the Port Cell is selected as representative event
for the TBP2 PIE.
In this PIE has been grouped also an unlikely contemporaneous rupture of the process line
and relative guard pipe in a section of the TES line running along the building from the Port
Cell to the TES Glove Box. In case, deterministic assessment of the TBP2 reference event
would show significant release of tritium inside Port Cell, the assumption here done has to be
reconsidered and if, even low, probability exists to have the above described double ruptures,
a new PIE has to be fixed and a further investigation have to evaluate amount of tritium that
could be released into the building and into the environment.
Loss of purge gas into Port Cell
Release of Tritium contained in TBM-BU and TES circuit into Port Cell
considered:
•
Use double containment around TES process line
•
Isolation of TES and TBM box to reduce the amount of gas released in Port Cell
•
Isolation of HVAC
•
TBL2
Small rupture from "TBM - Tritium Extraction System" process line inside
Glove Box containment
This PIE groups leaks from the TES circuit into the TES – Glove Box. A small rupture in the
TES piping located inside the secondary containment is selected as representative event for
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the TBL2 PIE. The section where also tritiated water could be released (e.g.: sump zone of the
cold trap) should be investigated by deterministic assessment.
Loss of purge gas and related tritium content into secondary containment
Possible tritium permeation from TES secondary containment to building.
considered:
•
Isolation of TES and TBM box to reduce the amount of gas released
•
Glove Box detritiation.
Similar PIEs has been already treated deterministically in [GSSR] assessing consequences of
failures related to Tokamak Exhaust Processing System.
VBG1 Loss of vacuum in VV: break inside the VV of TBM purge gas system
This PIE has been considered to take into account a significant rupture inside the vessel of the
TBM structure containing the purge gas. Particularly, the welds sealing the FSW with the two
Caps in the front of TBM have been considered. The event seems very hypothetical both
because the sealing is made by double welds (internal and external) and, because a leak
should occur before the break.
Plasma disruption
Rapid depressurization of TES because suction effects from VV
Loss of Be pebbles into VV due to VV suction effects. In this case, it is also worthwhile
to remark that the loosing of pebbles inside the VV makes more complicated recovery
actions inside the VV to clean vacuum chamber before restart. Consequences that could
reduce plant availability
Possible loss of leak tightness in purge gas system because sub-atmospheric pressure in
the circuit. In such a case, the following aggravating failures could follow:
-
Ingress of air in TES, TBM box and VV
-
Be-air reaction
Possible rupture in other water cooled PFCs due to disruption
VV over pressurization due to the steam release in the vessel
Ingress of steam into the TBM box if the VV pressure overcome the internal pressure of
the box
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Reaction between steam lost from PFCs and Be [Be pebbles inside the vessel (low T) &
Be pebbles remained in the TBM box (low T) & Be armour of PFCs (low T)]
H2 production
Risk of H2 explosion in case air gets in touch with H2.
considered:
•
Isolation of purge gas circuit to reduce the gas released in VV and risks due to TES
depressurization
•
Isolation of broken water cooled PFC circuit to reduce the coolant released in VV
•
•
Keep TBM cooling effective in order to quickly reduce temperature of Be pebbles
The VBG1 initiator seems to have similar but milder consequences then the ones related to
the LBV1 PIE because the TBM helium coolant is not discharged inside the vessel.
Therefore, for the public safety assessment, the LBV1 PIE can be selected as representative
PIE of the initiator inducing in-vessel break of TBM.
VBG2 Loss of vacuum in VV: leak inside VV from TBM purge gas system
Leaks from welds sealing the FSW with the two Caps in the front of TBM or from the two
short in-vessel pipes for the inlet/outlet of purge gas generate loss of vacuum inside the vessel
because purge gas ingress.
Same consequences then the ones described for the VBG1 PIE could follow, except for the
loss of Be pebbles into VV. Also mitigating actions could be the same.
VBG1 is most significant, with respect to this PIE, in terms of containments challenging and
VVA2 Ingress of air in the VV - small leakage
Loss of leak tightness in piping feedthroughs could determine an ingress of air into the VV
and a loss of vacuum. This PIE has been already determined by the FMEA on the VV.
Loss of VV leak tightness
Ingress of air in VV
Plasma disruption
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VV pressurisation
Opening of bleed lines towards VVPSS when VV pressure gets 80 kPa
Release of radioactive products contained in VV (tritium & dusts) to Port Cell if VV
pressure overcomes Port Cell pressure
considered:
•
Use double bellows in each pipe F/T
•
•
Maintain VV vacuum pumping system (rougly pumps) effective.
N/S
Not Safety Relevant
The PIE category N/S collects all the elementary events estimated as not leading to any public
safety relevant disturbance. Even if such failures are not important from a public safety point
of view, they will be important on worker safety in defining plant operability and
maintenance strategy.
6
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CONCLUSIONS
The systematic approach to the identification of potential hazards arising from EU HCPB
TBM systems has provided a comprehensive assessment of accident initiators. The FMEA
methodology has given a complete screening of the various causes that could induce failures
in the plant or simply a stop in the operating phases because of failures in HCPB TBM and
interfacing systems. Also a qualitative overview on accident sequences arising from each
elementary failure could be derived on FMEA tables looking at consequences description and
preventive/mitigating actions.
A list of 21, public safety relevant PIEs has been set assessing elementary failures related to
the different components of HCPB TBM systems. Each PIE has been discussed in order to
qualitatively identify accident sequences arising from each PIE itself. Deterministic analysis
will have to demonstrate the plant capacity in mitigating and, in every case, in withstanding
accident consequences, arising from the overall set of PIEs, below fixed safety limits.
Four PIEs were already pointed out by the FMEA on other ITER systems and already
documented in [GSSR]:
LFP2
Port Cell
LFV2 Small PFW/BLK in vessel LOCA. Equivalent break size: a few cm2
LVV2 Small rupture in the internal VV shell - equivalent break size: a few cm2
VVA2 Ingress of air in the VV - small leakage
The other seventeen PIEs pointed out by this study are:
FB1
FB2
HB1
LBB1 Loss of TBM cooling circuit inside breeder blanket box: Rupture of a sealing
weld
LBB2 Loss of TBM cooling circuit inside breeder blanket box: Leak of a sealing weld
LBO1 LOCA Out-VV because large rupture of TBM cooling circuit pipe inside TWCS
Room
LBO2 LOCA Out-VV because small rupture of TBM cooling circuit pipe inside TWCS
Room
LBO3 LOCA Out-VV because of rupture of tubes in a primary TBM-HCS HX
LBP1 LOCA Out-VV because of rupture of a TBM cooling circuit pipe inside Port Cell
LBP2 LOCA Out-VV because small rupture of TBM cooling circuit pipe inside Port
Cell
LBV1 Loss of TBM cooling circuit inside VV: Rupture of TBM-FSW
LBV2 Loss of TBM cooling circuit inside VV: Leak from TBM-FSW
LVP2 Small rupture of VV cooling circuit pipe inside Port Cell
TBL2 Leak of TBM - Tritium Extraction System process line inside Glove Box
containment
TBP2 Leak of TBM - Tritium Extraction System process line inside Port Cell
VBG1
VBG2
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Loss of vacuum in VV: break inside the VV of TBM purge gas system
Loss of vacuum in VV: leak inside VV from TBM purge gas system
Six of these events have been identified by the discussion on possible consequences as the
ones more relevant to be studied with deterministic assessments. They are:
•
FB1 followed by TBM in-vessel break because contemporaneous failure to shutdown
the plasma,
•
LBB1,
•
LBO3,
•
LBP1,
•
LBV1,
•
TBP2.
All elementary failures not inducing public safety relevant consequences have been classified
in a PIE named N/S (Not Safety relevant). Even if such failures are not important from a
safety point of view, they will be important on defining plant operability and maintenance
strategy, as well as they will be useful in evaluating worker safety.
REFERENCES
[DDD HCPB] Design Description Document for the European Helium Cooled Pebble Bed
(HCPB) Test Blanket Modules, December 2005
[NEUBER]
Neuberger H.; Integration of TBM Helium coolant system in ITER,
December 2005
[GSSR]
ITER-FEAT Generic site safety report
Appendix A
List of components treated by the FMEA and related Figures
- Component -
TBM
TBM-FSW
TBM-FSW-CoolCh
TBM-FSW-Be
TBM-Cap
TBM-Cap-CoolCh
TBM-FSW-CapWeld-Front
TBM-FSW-CapWeld-Rear
Description
Comment
Test Blanket Module
TBM - First Side Wall
1
2 plates, drilled for cooling channel and, welded together by hipping, after 1
bended
TBM - First Side Wall - Cooling Channel
42 channels (14 of 2-sweep-channels), about 1.7 m each
42
TBM - First Side Wall - Beryllium protective layer in the FW side
layer of 2 mm thick
1
TBM - Caps
2 caps each made by 2 plates, drilled for cooling channel and, welded 2
together by hipping
TBM - Caps - Cooling Channels
2 caps. Each cap about 25 channels of about 1.6 m
50
TBM - FSW - Welds to assemble the Caps with the FSW - part of the welds 1 double weld/FSW side x 3 sides/cap x 2 caps = 6 double welds
6
sealing the front part of the TBM volume hosting BUs
TBM - FSW - Welds to assemble the Caps with the FSW - small part of the welds 1 double weld/FSW side x 2 sides/cap x 2 caps = 4 short double welds
4
sealing the rear part of the TBM volume hosting He coolant manifolds
TBM-Grid
TBM-Grid-CoolCh
TBM-Grid-CapWeld
TBM-Grid-FSWWeld
TBM-Grid-BUWeld
TBM - Grid
TBM - Grid - Cooling Channel
TBM - Grid - Welds to assemble the Grid to Caps
TBM - Grid - Welds to assemble the Grid to FSW
TBM - Grid - Welds to assemble the BU to Grid
TBM-BU
TBM-BU-Canister
TBM-BU-Canister-CBP
TBM - Breeder Unit
TBM - BU - Canister
TBM - BU - Canister - Ceramic Breeder Pebbles
TBM-BU-Canister-BeP
TBM-BU-Canister-CP
TBM - BU - Canister - Beryllium Pebble Bed
TBM - BU - Canister - Cooling Plates
TBM-BU-Canister-Wrap
TBM - BU - Canister - Assembling Wrap
TBM-BU-SP
TBM-BU-SP-HeCoolWeld
TBM - BU - Supporting Plates
TBM - BU - Supporting Plates - Welds sealing He coolant from purge gas
Appendix A.1
N° of unit for
system
number of channels to be identified
20 welds
14 welds lateral plus 54 welds front site
18x4=72 welds
Figures
1
Fig. 1
Fig. 2
1
Fig. 3
20
68
72
Fig. 4
24 BUs
24
4 canisters / BU
96
Ceramic breeder (Li4SiO4 or Li2TiO3) pebbles of diameters in the range
0.2-0.6 mm (poly-disperse bed) and 0.8-1.0 mm (mono-sized) mm,
respectively
Be pebbles of diameters in the range 0.2-0.6 mm
The canisters are made of two cooling plates cooled with internal channels. 120
5 CPs / BU = 2 CPs / Canister
The canisters are closed by a metallic wrap, that keeps assembled the 24
pebble beds
1 Supporting Plate / BU
24
10 welds (2 welds/CP x 5 CP) +12 welds (4 welds/SP manifold x 3 SP 600
manifold) + 1 weld (purge pipe outlet) + 2 welds (He coolant in&outlet) =
25 welds/BU
List of Components of the EU HCPB TBM
N° of
systems
Fig. 5
Page 1 of 9
- Component -
Description
Comment
N° of unit for
system
1
235
TBM-PurgSepP
TBM-PurgSepP-Welds
TBM - Purge Gas Separation Plate
TBM - Purge Gas Separation Plate - Welds for sealing inlet gas from outlet gas
TBM-BottPM3
TBM-BottPM3-Welds
TBM - Bottom Plate Manifold 3
TBM - Bottom Plate Manifold 3 - Welds sealing between He coolant inlet to BU 12 linear welds x 10 cross flags of grid +
(or He coolant out from Grid & Caps) and outlet purge gas
3 linear welds x 14 lateral flags of grid +
1 linear weld x 6 parts of FSW +
1 linear weld x 6 parts of cap x 2 caps +
1 circular weld x 2 small pipe for purge gas in/out +
1 circular weld x 18 He cooling pipes =
200 welds in total
1
200
TBM-BottPM3-Ship
TBM - Bottom Plate Manifold 3 - Ships to collect He cooling outlet from BU
3
TBM-BottPM3-ShipWelds
TBM - Bottom Plate Manifold 3 - Welds to fix the Ships to the BottPM. They seal Each ship has two fillet welds (internal and external), each weld done by 4 24
between the He coolant inlet to BUs and the He coolant outlet from BUs
weld beads: one bead for each site of the ship. For a total of 24 welds
(3x2x4)
TBM - Bottom Plate Manifold 3 - Welds located in the internal ship zone, to seal 6 circular fillet welds/Ship x 3 Ships = 18 welds
18
pipes with He coolant outlet from BU to the BottPM. The welds separate the BU
He coolant outlet from the purge gas outlet
TBM-BottPM3-BUoutWelds
TBM-BottPM2
TBM-BottPM2-Welds
Appendix A.1
12 linear welds x 10 cross flags of grid +
3 linear welds x 14 lateral flags of grid +
1 circular weld x 18 small pipes for purge gas out +
1 circular weld x 1 small pipe for purge gas in +
1 circular weld x 36 He cooling pipes =
235 welds in total
3 Ships, each one collecting 6 outlet pipes from BUs
TBM - Bottom Plate Manifold 2 - Welds sealing between He coolant inlet to Grids 12 linear welds x 6 cross flags of grid +
& Caps (or He coolant outlet from FSW) and He coolant inlet to BU (or He 3 linear welds x 7 lateral flags of grid +
coolant out from Grid & Caps)
2 linear weld x 3 Ships +
2 semicircular weld x 3 Ships =
119 welds in total
1
119
N° of
systems
Figures
Fig. 6
Fig. 7
Fig. 8
Page 2 of 9
- Component TBM-BottPM1
TBM-BottPM1-Welds
Description
Comment
TBM - Bottom Plate Manifold 1 - Welds sealing between He coolant inlet to FSW 1 linear weld x 2 parts of FSW +
and He coolant inlet to Grid & Caps (or He coolant outlet from FSW)
2 semicircular weld x 3 Ships +
16 linear welds for bypass collector +
1 circular weld x 1 bypass outlet pipe =
37 welds in total
TBM-BottPM1-OutCollector
TBM - Bottom Plate Manifold 1 - Outlet Collector. Welds of the collector seal 16 linear welds for Outlet collector +
between He coolant inlet to FSW and He coolant outlet from BUs
1 circular weld x 1 Outlet pipe =
17 welds in total
TBM-BottPM1-InCollector
TBM - Bottom Plate Manifold 1 - Inlet Collector. Welds of the collector seal 16 linear welds for Inlet collector +
different zones of the He coolant inlet to FSW
1 circular weld x 1 Inlet pipe =
17 welds in total
TBM-Ship-SepP_In/OutWelds TBM - Separation plate inlet outlet in ship. Welds sealing He coolant inlet to TBM 2 linear weld x 3 Ships +
FSW from He coolant outlet from BUs
12 welds in total
TBM-BPM
TBM - Back Plate Manifold: High pressure closure plate towards vacuum vessel.
He coolant inlet a 8 MPa
TBM-BPM-Welds
TBM - Back Plate Manifold - Welds sealing between He coolant inlet to FSW and 1 linear weld x 2 parts of FSW +
VV
1 circular weld x 3 pipes (In/Out/Bypass He cool) +
21 welds in total
TBM-PP-IS
TBM-PP-IS-ElBlock
TBM-PP-IS-AttP
TBM-PP-IS-AttP-ShearKeys
TBM-PP-IS-AttP-FlexCartr
TBM-PP-IS-HeCoolFT
Appendix A.1
TBM - Port Plug - Interface System
TBM - Port Plug - Interface System - Electrical Strap Blocks to protect the system 2 Blocks installed on BPM and 1 block on PP
from the plasma halo currents and their large EM forces
TBM - Port Plug - Interface System - Attachment Plate: weld to FW and cap,
screw to BPM. Close race track with tightness weld
TBM - Port Plug - Interface System - Attachment Plate - Shear Keys: to fix TBM
box to PP and to cope with forces and torques in the toroidal - poloidal plane
N° of unit for
system
1
37
N° of
systems
Figures
Fig. 9
17
17
12
Fig. 11
1
Fig. 12
21
1
3
Fig. 13
Fig. 14
3
TBM - Port Plug - Interface System - Attachment Plate - Flexible Cartridges: to fix
4
TBM box to PP and to cope with radial forces and moments in the radial poloidal
plane
TBM - Port Plug - He coolant Pipe Feedthroughs
3 He coolant pipes (Inlet/Outlet/Bypass): 2 weld/pipe to connect TBM 3
lines (1 inside VV and 1 outside VV) and 1 external bellow to seal the VV
feedthroughs
Page 3 of 9
- Component -
Description
Comment
N° of unit for
system
2 He purge gas pipes (Inlet/Outlet): 2 weld/pipe to connect TBM lines (1 2
inside VV and 1 outside VV) and 1 external bellow to seal the VV
feedthroughs
TBD electrical feedthroughs for diagnostics: 1 external bellow/FT to seal
the VV feedthroughs
TBM-PP-IS-HePurgeFT
TBM - Port Plug - He Purge Gas Pipe Feedthroughs
TBM-PP-IS-DiagnFT
TBM - Port Plug - Electrical Feedthroughs for Diagnostics
TBM-PP-IS-Grip
TBM - Port Plug - Interface System - Gripping system: not yet defined
PP-Frame-WCoolCh
Port Plug - Frame - Water Cooling Channels: Front and lateral parts of the PP
PP-Shield-WCoolCh
PP-Rear-WCoolCh
PP-Flange-LipWeld
Port Plug - Shield - Water Cooling Channels: Shielding part of the PP
Water from the FW/BLK cooling circuit
Port Plug - Rear - Water Cooling Channels: Rear part of the PP and PP flange to Water from the VV cooling circuit
VV
Port Plug - Flange - Lip Welds
2*4 linear long welds
IPCE
IPCE-PP-Frame&ShieldWCoolPipes
Inter-space and Port Cell Equipment
IPCE - Water cooling Pipes (Inlet/Outlet) to cool down the frame and shielding
parts of the Port Plug. Water from the FW/BLK cooling circuit
IPCE-PP-Rear-WCoolPipes
2
IPCE-TES-Pipe
IPCE-TES-V1
IPCE - Water cooling Pipes (Inlet/Outlet) to cool down the Rear part and flange of
the Port Plug. Water from the VV cooling circuit
IPCE -Tritium Extraction System - Purge gas piping (Inlet/Outlet)
IPCE -Tritium Extraction System - Valve 1 to isolate TES loop from TBM
Located in Port Cell
IPCE-TES-V2
1
IPCE-TES-CheckV
IPCE -Tritium Extraction System - Check Valve in the inlet tube to the TBM to Located in Port Cell upstream to valve IPCE-TES-V1
1
stop the propagation of a rising pressure from the TBM side
IPCE -Tritium Extraction System - Pressure reducing Valve installed at the outlet Located in Port Cell downstream to valve IPCE-TES-V2
1
of the TBM to avoid over-pressurization of TES loop in case of He coolant leaks
inside TBM
IPCE - part of Helium Cooling System inside Inter-space and Port Cell (IPC) - He
coolant Piping (Inlet/Outlet/Bypass)
IPCE - part of HCS inside IPC - Valve 3 is a mass control valve to share the flow It is located inside the port cell and it is mounted on the pipe integration 1
between the outlet and the bypass lines from TBM.
cask. The dimension is not already fixed but the flow diameter will be
about DN 60.
IPCE - part of HCS inside IPC - Gas mixer to join the Helium flow of the outlet
1
line and the bypass line (T difference between the two gas flows can be up to 200
°C)
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to
measure Gas Pressures
measure Gas Temperatures
IPCE-TES-PrRedValve
IPCE-HCS-Pipe
IPCE-HCS-V3
IPCE-HCS-GasMixer
IPCE-HCS-I&C -P
IPCE-HCS-I&C -T
Appendix A.1
N° of
systems
Figures
Fig. 15
Water from the FW/BLK cooling circuit
8
1
Fig. 16
2
Located in Port Cell
2
1
Fig. 17
Fig. 18
Page 4 of 9
- Component -
Description
Comment
N° of unit for
system
IPCE-HCS-I&C -Q
measure Gas Flow Rates
HCS
Helium Cooling System
HCS-Pipe-Shaft&Building
Helium Cooling System - He coolant Piping routing in the Vertical Shaft and The lines have to run essentially about 5 m horizontally and 15 m 110
TCWS Vault to get the HCS area (EU_HCPB-He-Room)
vertically within the service shaft and again ~35 m horizontally in the
vault. Including U-bend expansion loops to mitigate thermal stresses due
to the high temperature operation conditions, it results in a total length for
the hot leg and cold leg of ~55 m. A total of 110 m. Internal diameter of
about 130 mm
HCS-Pipe-EU_HCPB-HeRoom
HCS-Recuperator
Helium Cooling System - He coolant Piping routing in the HCS area (EU_HCPB- Most of the pipes inside the He-Room are DN 100. Estimated a total 60
He-Room)
length of about 60 m
HCS - Recuperator / economizer
The requirement to have 50 °C as inlet temperature for the circulator 1
makes the use of an economizer necessary. The recuperator has to provide
a temperature difference between inlet and outlet of each stage of about
200 °K
HCS - Gas mixer to join the Helium flow of the Recuperator primary outlet line
1
and the circulator bypass line
HCS - Heat Exchanger (cooler)
A straight tube bundle HX with high pressure helium flowing inside the 1
tubes and low pressure water flowing outside
HCS - Dust Filter
It is installed in the cold leg of the main loop, just in front of the circulator, 1
accumulating residual dust and particles from fabrication, and erosion
particles down to a size of typically E-6 m.
HCS-GasMixer
HCS-HX
HCS-Filter
The HCS is housed in the TCWS vault at the CVCS level, approximately 1
40 m away from the TBM in the EU-HCPB-He-Room
HCS-Circulator
HCS - Circulator
A variable speed He circulator installed in the cold leg of the primary loop 1
operating at (max) 50 °C inlet temperature. An encapsulated type
circulator with vertical shaft is envisaged. Design temperature 50 °C
(maximum temperature 100 °C at the outlet short term at reduced flow for
the TBM conditioning phases). Pressure 8 MPa
HCS-Heater
HCS - Electrical Heater
It needs for baking the test module first wall at 240 °C and for heating the 1
whole HCS to operating temperatures after maintenance or repair periods.
Furthermore the heater is needed for the NT-TBM for Tritium release
experiments at 500 °C. During TBM operation the heater is supposed to be
off state or only used for T control at a very low power level. During hot
standby the heater has to keep the He T of the circuit at a constant level
HCS-V1
HCS - Valve 1 to control the mass flow through the circuit
The diameter of the pipe on which the valve is mounted is not already 1
estimated but it may be lower than DN 80
Appendix A.1
N° of
systems
1
Figures
Fig. 17
Page 5 of 9
- Component HCS-V2
HCS-V4
HCS-V5
HCS-V6
Description
Comment
N° of unit for
system
1
HCS - Valve 7 (gate valve) used only to close the TBM outlet line for TBM It is supposed to be DN 100
removal in order to keep the He inside the HCS. It is closed together with Valve 6
HCS-V8
HCS - Valve 8 (gate valve) to bypass the whole TBM piping through the ITER This design feature makes possible a testing of the whole circuit without a 1
building including the TBM. It is open when Valves 6 and 7 are closed
TBM.
It is supposed to be DN 100
PCS
Pressure Control System
PCS-StorageT
PCS-BufferT
PCS-SourceT
PCS-Compressor
PCS-V1
PCS-V2
PCS-V3
PCS-V4
PCS-V5
PCS-V6
PCS-V7
PCS-V8
PCS-V9
PCS-V10
PCS-V11
PCS-Pipe
PCS - Storage Tank
PCS - Buffer Tank
PCS - Source Tank
PCS - Helium compressor
PCS - Valve 1 is the connection to the external Helium supply
PCS - Valve 2 connecting Buffer tank to circulator downstream line
PCS - Valve 3 connecting Buffer tank to circulator upstream line
PCS - Valve 4 connecting Storage tank to circulator downstream line
PCS - Valve 5 connecting Storage tank to circulator upstream line
PCS - Valve 6 connecting Source tank to circulator downstream line
PCS - Valve 7 connecting Source tank to circulator upstream line
PCS - Valve 8 in the circulator bypass line
PCS - Valve 9 to isolate the circulator inlet line
PCS - Valve 10 to isolate the circulator outlet line
PCS - Valve 11 to connect the PCS to the HCS
PCS - Piping in the Pressure Control System
CPS
CPS-Water Separator-1
Coolant Purification System
CPS - Water Separator to remove condensed water
Appendix A.1
Figures
HCS - Valve 2 to control the secondary circuit of the cooler to have influence on
the circulator inlet temperature
HCS - Valve 4 to control the economizer bypass. It works together with Valve 5 The whole mass flow can pass through it so its dimension have to be DN 1
100
HCS - Valve 5 to control the economizer secondary stage inlet. It works together The whole mass flow can pass through it so its dimension have to be DN 1
with Valve 4
100
HCS - Valve 6 (gate valve) used only to close the TBM inlet line for TBM removal It is supposed to be DN 100
1
in order to keep the He inside the HCS. It is closed together with Valve 7
HCS-V7
CPS-Heater-2a
N° of
systems
1
It ensures a constant pressure level of the HCS (8 MPa) even during 1
changing operating conditions
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Fig. 19
1
Item 1 in the Figure.
1
It will not be used under normal conditions, i.e. as long as no liquid water
is contained in the gas of the cooling system
CPS - Electrical Heater (2a) to increase the T of the He stream to 450° C, i. e. to Item 2a in the Figure
1
the operation temperature of the catalytic oxidizer
1
Fig. 20
Page 6 of 9
- Component -
Description
Comment
N° of unit for
system
1
CPS-Oxidezer-3
CPS - Catalytic oxidizer to convert the hydrogen isotopes Q2 to Q2O (Q=H,T)
Item 3 in the Figure
CPS-Cooler-4
CPS - Water Cooler to reduce the temperature of the gas to room temperature.
It is designed as a double-pipe HX conducting an air stream in the jacket 1
and the helium stream in the inner tube that may be installed as a spiral.
CPS-Blower-5
CPS - Blower
CPS-Adsorber-6a/6b
CPS - Adsorbers: 2 Molecular Sieve Beds
1
CPS could operate without an additional compressor, but the blower is
available on demand
The adsorber beds are filled with 5A zeolite pellets that adsorb the water 2
content as well as gaseous impurities like N2. The beds contain filters on
the down-stream and upstream side to prevent particulate material from
being transferred during loading or unloading operations. In addition each
bed is equipped with an electrical heater for regeneration. The second bed
provides additional adsorption capacity; it may be used when the first bed
has not been unloaded or regenerated.
Items 6a & 6b in the Figure
CPS-Heater-2b
CPS - Electrical Heater (2b) to warm up the gas coming from the adsorbers (No. Item 2b in the Figure
1
6a/b)
1
CPS - Relief Tank
The relief tank has two tasks:
1) to act as a buffer tank during depressurisation of single components (in
particular, it is used for the molecular sieve beds prior the warm-up
operation),
2) to store the desorbing impurities, which are released from the adsorber
bed during the regeneration operation. These impurities are later on sent to
the Waste Gas System.
CPS-ReliefT-7
CPS-HeMakeUp
CPS - Helium Make-up Unit
CPS-Valves
CPS - Valves need to operate the circuit
CPS-Pipe
PCS - Piping in the Coolant Purification System
TES
TES-Pipe-Shaft&Building
Tritium Extraction System
1
TES - He purge gas Piping routing in the Vertical Shaft and Building to get the A double pipe is foreseen to have a double containment of the gas stream. 400
TES glove box in the tritium building
A notional value of 200 m has been assumed for the length of the two
pipes (Inlet/Outlet) from PC to GB for a total of 400 m. Internal diameter
of 120 mm
TES-Pipe-GB
TES - He purge gas Piping routing inside the TES glove box: process line in GB
Appendix A.1
N° of
systems
Figures
It is used to add hydrogen and water to CPS to provide a H2 with a partial 1
pressure of about 300 Pa and H2O of about 35 Pa
26 valves in the circuit: 12 valves are opened during NO and the 26
remaining 14 valves are closed
A notional value of 50 m has been assumed
1
Fig. 21
50
Page 7 of 9
- Component TES-V3
TES-V4
TES-V5
TES-V6
TES-Valves
Description
Comment
N° of unit for
system
1
1
1
1
Figures
TES - Valve 3 to isolate TES loop from TBM
TES - Valve 5 to operate TES loop bypassing the TBM
TES - Valve 6 to open a short loop to purge the TBM without operating the
extraction line of the TES
TES - Valves not identified by label, which need to operate the circuit
21 valves in the circuit: 13 valves are opened during NO and the 21
remaining 8 valves are closed
TES-Cooler-1
TES - Cooler
TES-Filter-2
TES - Filter
TES-IonChamber-3a/b
TES - Ionization Chamber
TES-ColdTrap-4
TES - Cold Trap
TES-Recuperator-5
TES - Recuperator
1
D: 800 H: 1600
It has the task to further reduce the temperature of the gas leaving the cold
trap (gas 1) by utilizing the clean gas leaving the adsorber (gas 2)
TES-LTAdsorber-6 a/b
TES - Low Temperature Adsorber
1
D: 900 H: 3000
The adsorber beds are filled with 5A zeolite pellets which adsorb
molecular hydrogen as well as gaseous impurities and residual moisture.
The beds contain filters on the down-stream and upstream side to prevent
particulate material from being transferred during loading or unloading
operations. In addition, each bed is equipped with a LN2 chiller and an
electrical heater
TES-Heater-7
TES - Heater
D: 200 H: 500
The heater is used to warm up the gas coming from the recuperator
1
TES-Compressor-8
TES - Compressor
L: 600 W: 600 H: 800
1
Appendix A.1
N° of
systems
D: 150 H: 700
1
It is designed as a heat exchanger containing cold water in the shell and
the purge gas (helium) in the inner tube bundle.
D: 60 H: 500
1
It is used to remove particulate material which might be carried out from
the blanket zone
D: 200 H: 400 (each)
2
2 Tritium Monitors are installed in a bypass, in parallel to the main loop.
In addition, the bypass line contains two manually operated valves which
can be closed for exchange of the monitor.
D: 500 H: 1300
1
The Q2O content (Q = H,T) of the gas is frozen out in the cold trap which
is operated at < -100°C. The amount of ice accumulated within 6 days is
of the order of a few grams (max. 6 g). The trap is cooled with LN2.
Filling level and temperature are continuously controlled. A heating coil in
the centre of the trap is used for recovery of liquified water which is
drained into a water collector.
Page 8 of 9
- Component -
Description
Comment
N° of unit for
system
1
TES-HeMakeUp-9
TES - Helium Makeup Unit
L: 1000 W: 400 H: 2000
In the He make-up unit hydrogen is added to provide a He/H2 swamping
ratio of 1000 for the gas re-entering the blanket test module. In addition,
this component is used for the first fill-up of the loop with helium and for
compensating smaller He losses due to leakages. It is installed in a casing
outside of the glove box
TES-Water Collector-10
TES - Water Collector
D: 100 H: 320
1
The liquefied water from the cold trap is drained into an evacuated water
collector which is later on transferred to the Water Detritiation System
TES-Blower-11a
TES - Blower
TES-ReliefT-12
TES - Relief Tank
L : 500 W : 500 H : 300
1
The blower is installed in the secondary loop of the adsorber beds
D: 1000 H: 2600
1
It is of 2 m³, it is available to restrict the pressure increase during
desorption in the warm-up phase of the adsorber to a value below 0.2 MPa
TES-Blower-11b
TES - Blower
TES-Diffusor-13
TES - Diffuser
TES-GetterBed-14
TES - Getter Bed (2 Units)
TES-HeBufferVessel-15
TES - Helium Buffer Vessel
TES-Blower-11c
TES - Blower
TMS
Tritium Measurement System. It will replace the TES during a part of the NT- TMS has not been evaluated in the FMEA because the assessment has
TBM operation to perform measurement of tritium production
been done for the most critical conditions that could be generated for the
PI-TBM foreseen for the high-duty D-T-phase of ITER-FEAT. Faults in
TMS should generate milder consequences than faults in TES during PITBM phase
NMS
Neutron Measurement System to measure neutron fluxes and spectra in the TBM
Appendix A.1
N° of
systems
Figures
L : 500 W : 500 H : 300
1
To sent the gas of the relief tank to the Waste Gas System
D: 130 H: 1200
1
A Pd/Ag diffuser to separate the hydrogen isotopes from the helium carrier
gas
D: 350 H: 750 (each)
2
Two ZrCo-getter beds are provided for storage of the hydrogen isotopes
1
D: 200 H: 400
It is used to supply the transport gas (helium) for the gas loop at the
secondary side of the diffuser
L : 500 W : 500 H : 300
1
To let circulation of gas in the secondary side of the diffuser
Not yet defined by design - Not assessed by the FMEA
Page 9 of 9
TBM-Cap-Cooling Channels
TBM-FSW-Cooling Channels
Fig. 1 - TBM First Side Wall
Appendix A.2
Fig. 2 - TBM Caps
Figures related to the TBM - EU HCPB
Page 1 of 13
TBM-FSW-CapWeld
TBM-Grid-BUWeld
TBM-Cap
TBM-Grid-FSWWeld
TBM-FSW
TBM-Grid
TBM-Grid-CapWeld
Fig. 3 - TBM grid installation
Appendix A.2
Fig. 4 - Breeder Unit installation
Page 2 of 13
Purge gas inlet
TBM-PurgSepP: purge gas Inlet is inside & purge gas Outlet is outside
Purge gas outlet
Fig. 5 - Breeder Unit
Purge gas outlet
TBM-PurgSepP-Welds
Fig. 6 - Purge gas separation plate
Appendix A.2
Page 3 of 13
TBM-BottPM3: purge gas outlet is inside & BU He coolant inlet is outside
TBM-BottPM3-Ship
He outlet from BU
He outlet from grid
TBM-BottPM2: BU He coolant inlet is inside & He coolant out from FSW is outside
He inlet to BU
He outlet from BU
He outlet from Caps
TBM-BottPM3-Welds
He outlet from FSW
Fig. 7 - TBM - Bottom Plate Manifold 3
He inlet to Grids
He inlet to Caps
TBM-BottPM2-Welds
Fig. 8 - TBM - Bottom Plate Manifold 2
Appendix A.2
Page 4 of 13
TBM-BottPM1: He coolant inlet to Grids & Caps (or He coolant outlet from FSW) is inside & He coolant inlet to FSW is outside
outlet from BU
He outlet fromHe
TBM
He Outlet collector
He Inlet distribution
He inlet to FSW
TBM-BottPM1-Welds
TBM-BypassCollector
Fig. 9 - TBM - Bottom Plate Manifold 1 (old version without bypass)
Fig. 10 - TBM - Bottom Plate Manifold 1 and collectors (new version with bypass
Appendix A.2
Page 5 of 13
TBM-Ship-SepP_In/Out: He coolant outlet from BUs is inside & He coolant inlet to TBM-FSW is outsideTBM - Back Plate Manifold: High pressure closure plate towards vacuum vesse
He Inlet distribution
He outlet from TBM
He inlet to TBM
TBM-BPM-Welds
TBM - Back Plate Manifold: High pressure closure plates of ‘ship
TBM-Ship-SepP_In/OutWelds
Fig. 11 - TBM - Separation plate inlet/outlet in ship and inlet distribution
(old version without bypass)
Fig. 12 -
TBM - High pressure closure plate towards vacuum vesse
High pressure closure plates of ‘ships’
(old version without bypass)
Appendix A.2
Page 6 of 13
TBM - Attachment Plate
TBM - AttP - Flexible Ca
TBM-BPM-Electrical Strap
TBM-PP-ElStrap-Block
TBM-AttP-Shear Keys
Fig. 14 - TBM - Attachment Plate
(old version without bypass and without Electrical Straps)
TBM-BPM-ElStrap-Blocks
Fig. 13 - TBM - Port Plug - Interface System - Electrical Straps between TBM Box and Port Plug
Appendix A.2
Page 7 of 13
TBM-PP-IS-DiagnFT-Bellow
Fig. 15 - TBM - Port Plug - External Interface System
Appendix A.2
Page 8 of 13
Fig. 16 - IPCE Piping
Appendix A.2
Page 9 of 13
IPCE-HCS-components
Fig. 17 - Helium Cooling System
Appendix A.2
Page 10 of 13
Fig. 18 - IPCE components
Appendix A.2
Page 11 of 13
Fig. 19 - Schematic drawing of the Pressure Control System (PCS)
Fig. 20 - Flow Sheet of the Coolant Purification Subsystem (CPS)
Appendix A.2
Page 12 of 13
Fig. 21 - Flow Sheet of the Tritium Extraction Subsystem
Appendix A.2
Page 13 of 13
Appendix B
FMEA Table for EU HCPB TBM
Component
TBM-FSW
Op.
St.
Failure Mode
NO Rupture
Causes
Prev.Action on
Causes
Material defects;
Impact of heavy loads
(missile inside VV);
Abnormal operating
conditions (e.g.: vibrations);
Fatigue;
Arcs due to halo currents
Test during
manufacturing &
assembly;
In-vessel viewing;
Optimize maintenance
procedures
Consequences
Loss of He coolant into VV;
Plasma disruption;
VV pressurisation;
Pressure relief towards VVPSS;
Release of RadP_VV to VVPSS
Possible local VV pressurization over design limits in
case of particular dynamic effects or fault in VVPSS
devices opening;
Possible loss of leak tightness in FTs or windows of VV;
Release of RadP_VV to Port Cell
Appendix B
Corr./Prev. Act. on Consequence
PIEs
LBV1
Comment
Missile should not get TBM because
magnetic fields inside the vessel
should accelerate foreign objects
towards inboard zone and not
towards outboard zone. In any case,
such remote cause has to be
excluded by a dedicated analysis
Periodic testing & maintenance of
VVPSS devices;
Design VVPSS to treat over
pressurization generated by He gas
Loss of purge gas into VV;
Provide TES with dedicated
Possible pressurization of purge gas system (TES) up to devices to avoid pressurization of
the circuit by gases coming from
VV pressure;
TBM box side (He coolant and/or
Possible loss of leak tightness in purge gas system;
Release of RadP_VV and RadP_TES to Port Cell and/or steam);
Isolation of TES
to GB according the leak location in the TES circuit
TES is designed to withstand 2MPa,
therefore VVPSS should manage to
keep VV pressure at lower values,
i.e.: leaks from TES should be
prevented
Loss of Be pebbles into VV due to dynamic effects (e.g.
VV suction, He flowing) caused by the FW rupture
This event makes more complicated
recovery actions inside the VV to
clean vacuum chamber before restart
Possible rupture in other water cooled PFCs due to
disruption;
VV over pressurization due to the combined effects of He
and steam;
Reaction between steam lost from PFCs and Be [Be
pebbles inside the vessel (low T) & Be pebbles remained
in the TBM box (high T) & Be armour of PFCs (low T)];
H2 production;
Isolation of broken circuits to
reduce the coolant released in VV;
pressurization
generated
by
mixture of He gas and steam;
Increase cooling capability of
effective circuits in order to
quickly reduce temperature of
PFCs and VV structures
Increase of ORE for recovery actions
Apply detailed procedures (defined
in an ALARA context) performing
recovery activities
FMEA Table for Eu HCPB TBM
Pebbles of Be released in VV should
be cooled down by the water
entering the VV. Consequently,
related Be-water reaction should
have milder effects;
But, on the other hand, they leave
more space available to steam that
could enter the TBM box and could
react with pebbles remained in the
box
Page 1 of 47
Component
TBM-FSW
Op.
St.
Failure Mode
NO Plate deformation
Causes
Material defects;
Abnormal operating
conditions (e.g.: thermalmechanical stress not
foreseen by design)
Prev.Action on
Causes
Test during
manufacturing &
assembly;
In-vessel viewing
Consequences
Possible rupture in case of progressive deformation or
persisting of abnormal conditions
PIEs
Comment
LBV1
Even if the deformation is
progressive during the TBM
operating time and it is not detected,
conditions inducing rupture of the
FSW seems be hypothetical during
the short operating life of TBM box
because the stiffening of internal
grid
The opening of the bypass could be
progressive
because
the
impossibility to detect the break and
the high pressure inside the cooling
channels
Possible complete or partial plugging of cooling channel
due to the deformation;
Increase of temperature in local zone of the FSW because
the disturbance in coolant flow;
Possible break due to over thermal-mechanical stress;
Consequences as for the "TBM-FSW - Rupture" could
follow
TBM-FSW
NO Break in internal Material defects;
hipping joint
Defects in manufacturing
Test during
manufacturing &
assembly
Opening of bypass between adjacent cooling channels;
follow
LBV1
TBM-FSW-CoolCh NO Partial or complete Defects in manufacturing
Test during
plugging
channel surfaces, which
manufacturing &
determine metal detachment assembly
or rising of obstruction;
Parts of metallic components
detached from HCS
components and transported
by the He flow inside TBM
(e.g.: flake from circulator
blade or HX or piping)
follow
LBV1
Appendix B
Page 2 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
Comment
TBM-FSW-Be
NO Detachment of Be Material defects;
layer from FSW
Defects in manufacturing;
Abnormal operating
foreseen by design)
TBM-Cap
NO Rupture
Material defects;
Test
during Consequences as for the "TBM-FSW - Rupture" could
Abnormal operating
manufacturing
& follow
conditions (e.g.: vibrations); assembly
Fatigue
LBV1
TBM-Cap
Material defects;
Abnormal operating
foreseen by design)
Test during
manufacturing &
assembly
Possible rupture in case of progressive deformation or
persisting of abnormal conditions;
follow
LBV1
Even if the deformation is
progressive during the TBM
operating time and it is not detected,
conditions inducing rupture of the
Caps should be hypothetical during
the short operating life of TBM box
because the stiffening of internal
grid
TBM-Cap
NO Break in internal Material defects;
hipping joint
Defects in manufacturing
Test during
manufacturing &
assembly
Opening of bypass between adjacent cooling channels;
Increase of temperature in local zone of the Caps because
follow
LBV1
The opening of the bypass could be
progressive
because
the
impossibility to detect the break and
the high pressure inside the cooling
channels
Increase of temperature in local zone of the Caps because
follow
LBV1
Test during
manufacturing &
assembly
TBM-Cap-CoolCh NO Partial or complete Defects in manufacturing
Test during
plugging
manufacturing &
detached from HCS
Appendix B
Increase of temperature in local zone of the FSW because Design FSW with sufficient N/S
the loss of armour material;
margins to withstand thermal loads
also without Be layer
follow
Credit has been given to the
possibility to operate TBM also
without armour material
Page 3 of 47
Component
TBM-FSWCapWeld-Front
Op.
St.
Failure Mode
NO Loss
of
tightness
Causes
leak Defects in manufacturing;
Abnormal operating
conditions (e.g.: vibrations
and/or thermal-mechanical
stress not foreseen by
design);
Fatigue
Prev.Action on
Causes
Test during
manufacturing &
assembly
Consequences
Comment
Isolation of purge gas circuit to VBG2
Plasma disruption;
reduce the gas released in VV and
Rapid depressurization of TES because suction effects risks due to TES depressurization
from VV;
because sub-atmospheric pressure in the circuit;
Ingress of air in TES, TBM box and VV;
Be-air reaction
Possible rupture in other water cooled PFCs due to Isolation of broken circuits to
disruption;
VV over pressurization due to the steam release in the Increase cooling capability of
vessel;
Ingress of steam into the TBM box if the VV pressure quickly reduce temperature of
PFCs and VV structures;
overcome the internal pressure of the box;
Reaction between steam lost from PFCs and Be [Be Keep TBM cooling effective in
pebbles inside the TBM box (low T) & Be armour of order to quickly reduce temp. of
PFCs (low T)];
Be pebbles
H2 production;
Appendix B
PIEs
Very low amount of water can enter
the TBM box in any case
Page 4 of 47
Component
TBM-FSWCapWeld-Front
Op.
St.
Failure Mode
NO Rupture
Causes
Same as for "Loss of leak
tightness"
Prev.Action on
Causes
Consequences
PIEs
Plasma disruption;
reduce the gas released in VV and
Rapid depressurization of TES because suction effects risks due to TES depressurization
from VV;
Loss of Be pebbles into VV due to VV suction effects;
because sub-atmospheric pressure in the circuit;
Ingress of air in TES, TBM box and VV;
Be-air reaction
Comment
This event seems very hypothetical
because a leak should occur before
the
break
(with
milder
consequences) and because the
sealing is made by double welds
(internal&external);
disruption;
VV over pressurization due to the steam release in the Increase cooling capability of
vessel;
Ingress of steam into the TBM box if the VV pressure quickly reduce temperature of
overcome the internal pressure of the box;
Reaction between steam lost from PFCs and Be [Be Keep TBM cooling effective in
pebbles inside the vessel (low T) & Be pebbles remained order to quickly reduce temp. of
in the TBM box (low T) & Be armour of PFCs (low T)]; Be pebbles
H2 production;
TBM-FSWCapWeld-Rear
NO Loss
of
tightness
Isolation of broken circuits to LBV2
Test
during Loss of He coolant into VV;
Abnormal
operating manufacturing
& Plasma disruption;
conditions (e.g.: vibrations assembly
VV pressurisation;
recovery activities
Release of RadP_VV to VVPSS;
design);
Increase of ORE for recovery actions, e.g.: replacement of
rupture disks if they open
Fatigue
This event seems very hypothetical
because the sealing is made by
double welds (internal&external),
the length of welds is very short and
stiffness given by manifold plates
should avoid deformations that could
impair these welds
disruption;
VV over pressurization due to the combined effects of He Increase cooling capability of
and steam;
Reaction between steam lost from PFCs and Be armour; quickly reduce temperature of
H2 production;
Appendix B
Page 5 of 47
Component
TBM-Grid
Op.
St.
Failure Mode
Causes
NO Local deformation Material defects;
Abnormal operating
foreseen by design)
Prev.Action on
Causes
Consequences
Test during
manufacturing &
assembly;
Design with sufficient
margins to avoid
deformations
Local increase of one of the gaps between cooled plate
grid and BU;
Increase of temperature in local zone of the affected BUs;
Swelling of Be pebbles;
Changing of multiplier material properties
PIEs
LBB2
Rupture of the "TBM-BU-Canister-Wrap" due to the Design BU and assembly technics
expansion of pebble bed;
as to keep very low the gap
Dispersion of pebbles inside TBM box;
between
"TBM-BU-CanisterFurther generation of empty spaces inside BU;
Wrap" and "TBM-Grid"
Further increase of temperature in pebble bed;
Further increase of swelling of pebbles
Comment
Swelling should interest a restricted
zone of pebble bed because, swelling
of not-well cooled pebbles reduces
the gap between grid and BU and
increase
cooling
effectiveness,
avoiding
spreading
of
the
phenomena. Aggravating events are
partially mitigated
Once the empty space has been
generated the effects on pebbles will
cycle according plasma cycles.
Therefore, fatigue phenomena could
challenge integrity of structures
Mechanical stress on "TBM-BU-Canister-CP" due to Design BU cooled structures and
vertical swelling of pebbles;
joints with enough margins to
Possible break in joint between "TBM-BU-Canister-CP" support cyclical effects of pebbles
and "TBM-BU-SP" due to over thermal-mechanical swelling and derived un-uniform
stress;
loads
Loss of He coolant into the TBM box;
See "TBM-BU-SP-HeCoolWeld - Loss of leak tightness"
TBM-Grid-CoolCh NO Partial or complete Defects in manufacturing
Test during
plugging
manufacturing &
detached from HCS
Increase of temperature in local zone of the Grid because
Possible deformation of grid plates;
Consequences as for the "TBM-Grid - Local deformation"
could follow
LBB2
Possible break in grid structure due to over thermalmechanical stress;
Appendix B
Page 6 of 47
Component
TBM-GridCapWeld
Op.
St.
Failure Mode
NO Rupture
Causes
Abnormal operating
design);
Fatigue
Prev.Action on
Causes
Consequences
Weld in both sides of Possible deformation of grid vertical plate;
the grid;
Test
during could follow
manufacturing
&
assembly
PIEs
LBB2
Possible collapse of TBM box in case of loss of He
coolant inside the box;
follow
TBM-GridFSWWeld
NO Rupture
Abnormal operating
design);
Fatigue
Weld in both sides of Possible deformation of grid horizontal plate;
the grid;
Test
during could follow
manufacturing
&
assembly
This consequence has not been
considered for the assigning of PIE,
because it becomes of relevance for
safety only in case other faults occur
to cause TBM box pressurization
LBB2
Possible collapse of TBM box in case of loss of He
coolant inside the box;
follow
TBM-GridBUWeld
NO Rupture
Appendix B
Abnormal operating
design);
Fatigue
Test
during Loss of a BU joint to the grid;
manufacturing
& Reduction of BU stiffness;
assembly
Increase of vibrations inside TBM box
Comment
This consequence has not been
considered for the assigning of PIE,
because it becomes of relevance for
safety only in case other faults occur
to cause TBM box pressurization
N/S
Page 7 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
TBM-BU-Canister- NO Abnormal swelling Abnormal
operating Perform
dedicated Changing of breeder material properties
CBP
of pebbles
conditions (e.g.: unforeseen R&D on stability of
pebble
bed
in
heat load);
Un-uniform distribution of operating conditions
heat load into the pebble bed
(e.g.: the one inducing major
swelling in the front plasma
zone with respect to the rear
zone)
PIEs
LBB2
Mechanical stress on "TBM-BU-Canister-CP" due to
Possible break in joint between "TBM-BU-Canister-CP"
and "TBM-BU-SP" due to over thermal-mechanical
stress;
packaging
of Test
during Low thermal conductivity between pebbles and/or
TBM-BU-Canister- NO Generation
of Incorrect
empty spaces inside pebbles;
manufacturing
& between pebbles and cooling structure;
CBP
the canister
Pulverization of pebbles assembly;
during BU life;
Perform
dedicated Swelling of Ceramic Breeder Pebbles;
Increasing of compaction in R&D on stability of Changing of breeder material properties
bed
in
pebble bed during BU life; pebble
Abnormal
operating operating conditions
Rupture
of
"TBM-BUCanister-Wrap"
stress;
loads
Appendix B
Comment
Abnormal swelling could interest
also Be pebbles and, in that case the
loads on the opposite site of the
cooling plate compensates the loads
due to the breeder pebbles, but the
two materials could have different
swelling rates
LBB2
empty volumes and increase cooling
effectiveness, avoiding spreading of
the phenomena. Aggravating events
are partially mitigated
Page 8 of 47
Component
Op.
St.
Failure Mode
Causes
TBM-BU-Canister- NO Abnormal swelling Abnormal operating
BeP
of pebbles
conditions (e.g.: unforeseen
heat load);
Un-uniform distribution of
heat load into the pebble bed
(e.g.: the one inducing major
swelling in the front plasma
zone with respect to the rear
zone)
Prev.Action on
Causes
Consequences
Perform
dedicated Changing of multiplier material properties
R&D on stability of
pebble
bed
in
operating conditions
stress;
PIEs
Comment
LBB2
Abnormal swelling could interest
also Be pebbles and, in that case the
loads on the opposite site of the
cooling plate compensates the loads
due to the breeder pebbles, but the
two materials could have different
swelling rates
Mechanical stress on "TBM-Grid" due to swelling of
pebbles;
Possible deformation of grid plates;
could follow during future operating cycles of TBM, e.g.:
when abnormal swelling will be reduced by the cooling
down effect, at the end of the pulse or of the operating
campaign, and TBM reheated
between
"TBM-BU-CanisterGeneration of empty spaces inside BU;
Low thermal conductivity between pebbles and/or
between pebbles and cooling structure;
Appendix B
Page 9 of 47
Component
Op.
St.
Failure Mode
Causes
TBM-BU-Canister- NO Generation
of Incorrect packaging of
empty spaces inside pebbles;
BeP
the canister
Pulverization of pebbles
during BU life;
Increasing of compaction in
pebble bed during BU life;
Abnormal operating
conditions (e.g.: vibrations)
Prev.Action on
Causes
Consequences
Test
during Low thermal conductivity between pebbles and/or
manufacturing
& between pebbles and cooling structure;
assembly;
Perform
dedicated Swelling of Be pebbles;
R&D on stability of Changing of multiplier material properties
pebble
bed
in
operating conditions
between
"TBM-BU-CanisterFurther generation of empty spaces inside BU;
Further increase of temperature in pebble bed;
PIEs
LBB2
Comment
empty volumes and increase cooling
effectiveness, avoiding spreading of
the phenomena. Aggravating events
are partially mitigated
stress;
loads
Appendix B
Page 10 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
TBM-BU-Canister- NO Partial or complete Defects in manufacturing
Test
during Increase of temperature in local zone of the CP because
CP
plugging
manufacturing
& the disturbance in coolant flow;
Swelling of Ceramic Breeder Pebbles;
Changing of breeder material properties;
detached from HCS
PIEs
Comment
LBB2
vertical swelling of pebbles and defective cooling of joints with enough margins to
plate;
support cyclical effects of pebbles
Possible break in joint between "TBM-BU-Canister-CP" swelling and derived un-uniform
and "TBM-BU-SP" due to over thermal-mechanical loads
stress;
TBM-BU-Canister- NO Rupture
Wrap
Abnormal operating
design);
Fatigue
Test
during Dispersion of pebbles inside TBM box;
manufacturing
& Generation of empty spaces inside BU;
assembly
Low thermal conductivity between pebbles and/or
between pebbles and cooling structure;
stress;
Appendix B
Design BU and assembly technics LBB2
between
"TBM-BU-CanisterWrap" and "TBM-Grid"
Heat transmission between outer
layers of Be pebble beds and grid
plates is made by irradiation and
convection through purge gas (there
shouldn't be conductivity unless
material expansions after heat up
will cover the gaps required by the
assembly of BUs)
Design BU cooled structures and
support cyclical effects of pebbles
swelling and derived un-uniform
loads
Page 11 of 47
Component
TBM-BU-SPHeCoolWeld
Op.
St.
Failure Mode
NO Loss
of
tightness
Causes
Abnormal operating
design);
Fatigue
Prev.Action on
Causes
Test during
manufacturing &
assembly
Consequences
PIEs
Monitoring of TBM box pressure; LBB2
Pressurization of TBM box to He coolant pressure;
Isolation of TES to prevent over
Pressurization of TES;
pressurization;
Stop ITER operations to prevent
Release of Tritium from TES and TBM to Port Cell overstress on TBM box, which is
and/or to GB according the leak location in the TES getting critical conditions (8 MPa
circuit
internal pressure, vacuum outside)
Comment
TBM box is designed in order to
withstand He coolant pressurization
to 8 MPa
Perform TBM maintenance or set
TBM system in a way to continue
ITER pulses at least until next
plant shutdown (i.e.: interruption
of TBM experimental campaign);
The following measures could be
adopted according the needs:
closing of "IPCE-HCS-V3" valve
on bypass line, reduction of He
coolant pressure, partial isolation
of TES (bypass tritium extraction
components but keep effective
cooling of gas), etc.
TBM-BU-SPHeCoolWeld
NO Rupture
TBM-PurgSepPWelds
NO Loss
of
tightness
TBM-PurgSepPWelds
NO Rupture
Appendix B
tightness"
Abnormal operating
design);
Fatigue
tightness"
Consequences as for the "TBM-BU-SP-HeCoolWeld - See "TBM-BU-SP-HeCoolWeld - LBB1
Loss of leak tightness" could follow even if in this case Loss of leak tightness"
transient of over pressurization is faster
Test during
manufacturing &
assembly
Generation of a small bypass between inlet and outlet
purge gas manifolds, but differential pressure between the
two manifolds should remain enough high to let the
flowing through the BUs
N/S
Generation of a bypass between inlet and outlet purge gas Monitoring of pressure into the N/S
manifolds;
two manifolds
Equalization of pressures in the two manifolds;
Loss of purge gas flow into BUs;
High Tritium concentration in TBM;
Misrepresentation of experimental campaign data
Leak before break is quite difficult
to be monitored
Page 12 of 47
Component
Op.
St.
Failure Mode
TBM-BottPM3Welds
NO Loss
of
tightness
TBM-BottPM3Welds
NO Rupture
TBM-BottPM3ShipWelds
NO Loss
of
tightness
TBM-BottPM3ShipWelds
NO Rupture
TBM-BottPM3BUoutWelds
NO Loss
of
tightness
TBM-BottPM3BUoutWelds
NO Rupture
Appendix B
Causes
Abnormal operating
design);
Fatigue
Prev.Action on
Causes
Test during
manufacturing &
assembly
tightness"
Abnormal operating
design);
Fatigue
Test during
manufacturing &
assembly
tightness"
Abnormal operating
design);
Fatigue
tightness"
Test during
manufacturing &
assembly
Consequences
PIEs
Loss of He coolant into the purge gas outlet manifold and
consequently into TBM box;
Consequences as for the "TBM-BU-SP-HeCoolWeld Loss of leak tightness" could follow
LBB2
Consequences as for the "TBM-BU-SP-HeCoolWeld Rupture" could follow
LBB1
Generation of a small bypass between inlet and outlet of
He cooling BUs;
Impairing of capability to cool down BUs;
Consequences as for the "TBM-BU-Canister-CP - Partial
or complete plugging" could follow
LBB2
Generation of a bypass between inlet and outlet of He
cooling BUs;
Loss of He coolant flow into BUs;
Increase of temperature in affected BUs;
Over thermo-mechanical stress on BU structures;
Break in BU structure;
LBB2
Consequences as for the "TBM-BU-SP-HeCoolWeld Loss of leak tightness" could follow
LBB2
Consequences as for the "TBM-BU-SP-HeCoolWeld Rupture" could follow
LBB1
Comment
to be monitored
Page 13 of 47
Component
Op.
St.
Failure Mode
TBM-BottPM2Welds
NO Loss
of
tightness
TBM-BottPM2Welds
NO Rupture
TBM-BottPM1Welds
NO Loss
of
tightness
TBM-BottPM1Welds
NO Rupture
Appendix B
Causes
Prev.Action on
Causes
Test during
Abnormal
operating manufacturing &
design);
Fatigue
tightness"
Test during
Abnormal
design);
Fatigue
tightness"
Consequences
PIEs
Comment
He cooling the Grid and Caps;
Impairing of capability to cool down Grid and Caps;
Consequences as for the "TBM-Grid-CoolCh or TBMCap-CoolCh - Partial or complete plugging" could follow
LBB2
In terms of structure impairing, bad
cooling
of
grids
and,
consequentially, of BUs, should be
temporarely more effective then bad
cooling of caps. Therefore, "LBB2"
PIE has been assigned instead of
"LBV1" PIE
cooling the Grid and Caps;
Loss of He coolant flow into Grid and Caps;
Impairing of capability to cool down external layers of
BUs;
Over thermo-mechanical stress on BU, Grid and Caps
structures;
Break in BU structure;
LBB2
to be monitored;
cooling
of
grids
and,
cooling of caps. Therefore, "LBB2"
PIE has been assigned instead of
"LBV1" PIE
He cooling the FSW;
Impairing of capability to cool down FSW;
Consequences as for the "TBM-FSW-CoolCh - Partial or
complete plugging" could follow
LBV1
cooling the FSW;
Loss of He coolant flow into FSW;
Impairing of capability to cool down FSW;
Consequences as for the "TBM-FSW-CoolCh - Partial or
complete plugging" could follow
LBV1
Page 14 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
TBM-BottPM1OutCollector
NO Loss of weld leak Defects in manufacturing;
Test during
tightness
Abnormal
design);
Fatigue
He cooling the whole TBM;
Impairing the capability to cool down FSW, Grid, Caps
and BUs;
Consequences as for the "TBM-FSW-CoolCh or TBMGrid-CoolCh or TBM-Cap-CoolCh - Partial or complete
plugging" could follow
TBM-BottPM1OutCollector
NO Rupture
Generation of a bypass between inlet and outlet of He Activation of plasma shutdown in LBV1
cooling the whole TBM;
case temperature of He coolant
Loss of He coolant flow into FSW, Grid, Caps and BUs; outlet is too low with respect to
plasma conditions
Over thermo-mechanical stress on BU, Grid, Caps and
FSW structures;
Break in BUs and TBM structures;
follow
TBM-BottPM1InCollector
NO Loss of weld leak Defects in manufacturing;
Test during
tightness
Abnormal
design);
Fatigue
Generation of a small bypass between different zones of
He cooling inlet to FSW
N/S
TBM-BottPM1InCollector
NO Rupture
Generation of a bypass between different zones of He
cooling inlet to FSW;
Disturbance in He cooling flowing to FSW and possibility
to have no uniform FSW cooling;
Consequences as for the "TBM-FSW - Plate deformation"
could follow
N/S
He cooling the whole TBM;
Impairing the capability to cool down FSW, Grid, Caps
and BUs;
Consequences as for the "TBM-FSW-CoolCh or TBMGrid-CoolCh or TBM-Cap-CoolCh - Partial or complete
plugging" could follow
LBB2
TBM-ShipNO Loss
of
SepP_In/OutWelds
tightness
Appendix B
Same as for "Loss of weld
leak tightness"
Same as for "Loss of weld
leak tightness"
Abnormal operating
design);
Fatigue
Test during
manufacturing &
assembly
LBB2
Comment
cooling
of
grids
and,
cooling of FSW and caps. Therefore,
"LBB2" PIE has been assigned
instead of "LBV1" PIE
cooling
of
grids
and,
cooling of FSW and caps. Therefore,
"LBB2" PIE has been assigned
instead of "LBV1" PIE
Page 15 of 47
Component
Op.
St.
Failure Mode
TBM-ShipNO Rupture
SepP_In/OutWelds
TBM-BPM-Welds NO Loss
of
tightness
Causes
Prev.Action on
Causes
tightness"
Test during
Abnormal
design);
Fatigue
Consequences
PIEs
Comment
Generation of a bypass between inlet and outlet of He Activation of plasma shutdown in LBV1
cooling the whole TBM;
case temperature of He coolant
Loss of He coolant flow into FSW, Grid, Caps and BUs; outlet is too low with respect to
plasma conditions
FSW structures;
follow
Plasma disruption;
VV pressurisation;
recovery activities
disruption;
and steam;
H2 production;
Appendix B
Page 16 of 47
Component
Op.
St.
Failure Mode
TBM-BPM-Welds NO Rupture
Causes
Prev.Action on
Causes
tightness"
Consequences
Plasma disruption;
VV pressurisation;
Release of RadP_VV to VVPSS
PIEs
Comment
LBV1
Possible local VV pressurization over design limits in Periodic testing & maintenance of
case of particular dynamic effects or fault in VVPSS VVPSS devices;
devices opening;
Possible loss of leak tightness in FTs or windows of VV; pressurization generated by He gas
Release of RadP_VV to Port Cell
disruption;
VV over pressurization due to the combined effects of He Design VVPSS to treat over
and steam;
pressurization
generated
by
Reaction between steam lost from PFCs and Be armour; mixture of He gas and steam;
H2 production;
recovery activities
TBM-PP-ISElBlock
NO Loss of electrical Defects in manufacturing;
Test during
contact
Incorrect installation;
manufacturing &
Abnormal
operating assembly
design);
Unscrewing of straps due to
vibrations
Generation of arcs between structures at different Monitoring
of
differential LVV2
electrical potential (e.g.: box structure and port plug);
electrical potential between TBM
Possible melting of Port Plug shield and consequent box and PP;
ingress of water in VV;
VV pressurisation;
Increase of ORE for recovery actions, e.g.: maintenance recovery activities
on bleed line valves
TBM-PP-IS-AttP
No significant consequences
Appendix B
Material defects;
Abnormal operating
foreseen by design)
Test during
manufacturing &
assembly
Without effectiveness of copper
straps, electrical connection between
TBM box and PP is only devoted to
TBM supports and piping, which
have high resistance. Therefore,
there could be conditions where
differential potential between box
and PP is very high;
(e.g.: during plasma disruption)
N/S
Page 17 of 47
Component
TBM-PP-IS-AttPShearKeys
Op.
St.
Failure Mode
NO Rupture
Causes
Material defects;
Abnormal operating
foreseen by design)
Prev.Action on
Causes
Consequences
PIEs
Comment
Test
during Loss of one out of the three supports of the module;
manufacturing
& High mechanical stress on piping and on their PP supports reduce the coolant released in VV
assembly;
of the inlet/outlet lines (i.e.: coolant and purge gas);
Design with sufficient Possible pipe break due to over thermal-mechanical stress
margins with respect and/or fatigue due to toroidal and poloidal loads;
to expected loads
Plasma disruption
VV pressurisation;
recovery activities
disruption;
and steam;
H2 production;
Appendix B
Page 18 of 47
Component
TBM-PP-IS-AttPFlexCartr
Op.
St.
Failure Mode
NO Rupture
Causes
Material defects;
Abnormal operating
foreseen by design)
Prev.Action on
Causes
Consequences
Test during
manufacturing &
assembly;
Design with sufficient
margins with respect
to expected loads
Loss of one out of the four cartridges of the module;
High mechanical stress on piping and on their PP supports
of the inlet/outlet lines (i.e.: coolant and purge gas);
Possible feedthrough break due to over thermalmechanical stress and/or fatigue due to radial loads;
Loss of VV leak tightness;
Plasma disruption
PIEs
Comment
VVA2
Ingress of air in VV;
VV pressurisation;
Opening of bleed lines towards VVPSS when VV recovery activities
pressure gets 90 kPa;
Increase of ORE for recovery actions, e.g.: maintenance
Release of RadP_VV to Port Cell if VV pressure Increase cooling capability of
overcomes Port Cell pressure
Maintain VV vacuum pumping
system (roughly pumps) active
TBM-PP-ISHeCoolFT
NO Loss
of
Test during
tightness of weld Abnormal operating
manufacturing &
located in VV
stress not foreseen by design)
Appendix B
Consequences as for the "TBM-BPM-Welds - Loss of reduce the coolant released in VV
leak tightness" could follow
Page 19 of 47
Component
TBM-PP-ISHeCoolFT
Op.
St.
Failure Mode
Causes
NO Loss of bellow leak Defects in manufacturing;
tightness
Abnormal operating
design);
Fatigue
Prev.Action on
Causes
Test during
manufacturing &
assembly
Consequences
PIEs
Comment
Use double bellows in each pipe VVA2
Ingress of air in VV;
F/T;
Plasma disruption;
VV pressurisation;
Opening of bleed lines towards VVPSS when VV recovery activities
pressure gets 90 kPa;
Release of RadP_VV to Port Cell if VV pressure Increase cooling capability of
system (roughly pumps) active
TBM-PP-ISHePurgeFT
NO Loss
of
Test during
tightness of weld Abnormal operating
manufacturing &
located in VV
Consequences as the ones described for the "TBM-FSW- reduce the gas released in VV and
CapWeld-Front - Loss of leak tightness" could follow
risks due to TES depressurization
TBM-PP-ISHePurgeFT
tightness
Abnormal operating
design);
Fatigue
Test during
manufacturing &
assembly
Use double bellows in each pipe VVA2
Consequences as for the "TBM-PP-IS-HeCoolFT - Loss F/T
of bellow leak tightness" could follow
TBM-PP-ISDiagnFT
tightness
Abnormal operating
design);
Fatigue
Test during
manufacturing &
assembly
Use double bellows in each F/T
Consequences as for the "TBM-PP-IS-HeCoolFT - Loss
Appendix B
VVA2
Page 20 of 47
Component
PP-FrameWCoolCh
Op.
St.
Failure Mode
NO Loss
of
tightness
Causes
Prev.Action on
Causes
leak Material defects;
Test during
Impact of heavy loads manufacturing &
(missile inside VV);
assembly;
Abnormal
operating In-vessel viewing
Arcs due to halo currents;
Overstress
due
to
pipe/channel plugging
Consequences
NO Loss
of
tightness
Test during
Abnormal
Overstress
due
to
PIEs
Isolation of broken circuits to LFV2
Loss of PFW/BLK water coolant into VV;
Plasma disruption;
VV pressurisation;
recovery activities
Reaction between steam and Be armour;
H2 production;
PP-ShieldWCoolCh
Test during
Abnormal
Overstress
due
to
Loss of VV water coolant into VV;
Isolation of broken circuits to LVV2
Plasma disruption;
VV pressurisation;
recovery activities
PP-Flange-LipWeld NO Loss
of
tightness
Test during
Abnormal
design);
Fatigue
Consequences as for the "TBM-PP-IS-HeCoolFT - Loss
This event is similar to a leak in a
PFC module (FW/BLK or Divertor)
PP-Rear-WCoolCh NO Loss
of
tightness
Appendix B
PFC module (FW/BLK or Divertor)
Loss of PFW/BLK water coolant into VV;
Isolation of broken circuits to LFV2
Plasma disruption;
VV pressurisation;
recovery activities
Reaction between steam and Be armour;
H2 production;
Comment
sector of the VV internal shell
VVA2
Page 21 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
IPCE-PPFrame&ShieldWCoolPipes
NO Loss
of
tightness
Test during
(missile inside Interspace); assembly
Abnormal
operating
Loss of PFW/BLK water coolant into Port Cell;
Isolation of broken circuits to LFP2
Pressurization of Port Cell;
reduce the coolant released in Port
Release of Tritium & ACPs contained in PFW/BLK loop Cell;
into Port Cell;
Possible loss of Port Cell confinement towards Service in an ALARA context) performing
Shaft and/or Gallery;
recovery activities
IPCE-PP-RearWCoolPipes
NO Loss
of
tightness
Test during
(missile inside Interspace); assembly
Abnormal
operating
Loss of VV water coolant into Port Cell;
Isolation of broken circuits to LVP2
Release of Tritium & ACPs contained in VV loop into Cell;
Port Cell;
recovery activities
IPCE-TES-Pipe
NO Loss
of
tightness
leak Incorrect installation;
Test during
Material defects;
manufacturing &
Impact of heavy loads assembly
(missile inside Interspace
and/or Port Cell);
Abnormal
operating
Loss of purge gas into Port Cell;
Use double containment around TBP2
Release of Tritium contained in TBM-BU and TES circuit TES process line;
into Port Cell;
Isolation of TES and TBM box to
Possible loss of Port Cell confinement towards Service reduce the amount of gas released
in Port Cell;
Isolation of HVAC;
recovery activities
IPCE-TES-V1
NO Valve external leak Seal failure
IPCE-TES-V1
NO Valve fail to open
or to remain open
IPCE-TES-V2
Appendix B
Preventive
maintenance
Control system failure;
Preventive
Loss of ancillary electr. maintenance
power;
Fault in pneumatic supply
system;
Actuator failure;
Human error
Preventive
maintenance
Consequences as the ones listed for the "IPCE-TES-Pipe TBP2
Loss of leak tightness"
Loss of flow in TES;
Monitoring of TES parameters N/S
(flow
rate,
pressure
and
Increase of Tritium concentration in TBM;
temperature);
Pressurization of TES line downstream compressor;
Stop TES compressors;
Pressurization of TBM box in volumes fulfilled by purge Use double containment around
gas;
TES process line
Increase of tritium permeation from TES process line to
Port Cell;
Increase of tritium permeation into HCS
Consequences as the ones listed for the "IPCE-TES-Pipe Loss of leak tightness"
Comment
Use of double containment inside PC
has to be assessed on the base of the
max amount of tritium that could be
released
The event has not been grouped in
TBP2 PIE because credit has given
to the detection system and to
capability
in
stopping
the
compressors;
released
TBP2
Page 22 of 47
Component
IPCE-TES-V2
Op.
St.
Failure Mode
or to remain open
Causes
Preventive
power;
system;
Actuator failure;
Human error
IPCE-TES-CheckV NO Valve external leak Seal failure
IPCE-TES-CheckV NO Valve fail to open
or to remain open
IPCE-TESPrRedValve
IPCE-HCS-Pipe
Mechanical failure
NO Loss
of
tightness
Appendix B
Prev.Action on
Causes
Preventive
maintenance
Preventive
maintenance
Preventive
maintenance
Test during
Material defects;
manufacturing &
and/or Port Cell);
Abnormal
operating
Consequences
PIEs
(flow
rate,
pressure
and
temperature);
Increase of tritium permeation from TES process line to Stop TES compressors;
Port Cell
Use double containment around
TES process line
(flow
rate,
pressure
and
temperature);
Increase of tritium permeation from TES process line to Stop TES compressors;
Port Cell
Use double containment around
TES process line
Loss of He coolant into Port Cell;
Isolation of broken circuits to LBP2
Release of Tritium contained in He coolant into Port Cell; Cell;
Possible loss of Port Cell confinement towards Service Isolation of HVAC;
recovery activities
Comment
capability
in
stopping
the
compressors;
released
capability
in
stopping
the
compressors;
released
Atmosphere detritiation can be
operated only when Port Cell
pressure is under set value (e.g.: 0.1
MPa)
Page 23 of 47
Component
IPCE-HCS-Pipe
Op.
St.
Failure Mode
NO Rupture
Causes
Prev.Action on
Causes
Test during
Material defects;
manufacturing &
and/or Port Cell);
Abnormal
operating
Consequences
PIEs
Loss of He coolant into Port Cell;
Monitoring of amount of He LBP1
contained in Port Cell to promptly
Release of Tritium contained in He coolant into Port Cell; detect leaks;
Possible loss of Port Cell confinement towards Service Isolation of broken circuits to
Cell;
Isolation of HVAC;
recovery activities
Comment
MPa)
Emptying of the TBM cooling loop and loss of heat
removal capability
Overheating of TBM;
Plasma shutdown
Swelling of Ceramic Breeder and Be pebbles;
FSW structures
Ingress of air in TBM box;
Isolation of TBM box
Be-air and Be-water (moisture contained in air) reactions
if coolant channels inside the box lost their integrity;
H2 production;
Benefit of the TBM box isolation
has to be carefully evaluated because
it requires the use of other 2 isolation
valves, respectively in the inlet and
outlet legs of TBM, which, on their
part, can cause LOFA in case of
spurious closing
Possible break of TBM box;
Ingress of He (i.e.: some coolant not yet discharged from
the loop and purge gas) and air (from the external break)
into VV;
Plasma disruption if it has not been actively or passively
(plasma poisoning due to armour material evaporation)
shutdown
The box break could occur also
without H2 explosion, only for the
effects of thermo mechanical stress
VV pressurisation;
Opening of bleed lines towards VVPSS when VV effective circuits in order to
pressure gets 90 kPa and opening of lines to drain tank quickly reduce temperature of
when p>110kPa;
Release of RadP_VV to Port Cell if VV pressure system (roughly pumps) active
Appendix B
Page 24 of 47
Component
IPCE-HCS-Pipe
(cntd)
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
NO Rupture
Consequences
PIEs
Comment
Aggravating consequences could occur in case of rupture Design VVPSS to treat over
in other water cooled PFCs due to disruption
pressurization
generated
by
mixture of He gas and steam
recovery activities
IPCE-HCS-V3
IPCE-HCS-V3
NO Valve failure
remain open
IPCE-HCS-V3
NO Valve
fail
to Instrument failure;
operate:
stuck Control system failure
completely opened
Preventive
maintenance
IPCE-HCSGasMixer
IPCE-HCSGasMixer
NO External leak
Seal failure;
Weld failure
Material defects;
Weld failure;
IPCE-HCS-I&C -P NO External leak
Seal failure
IPCE-HCS-I&C -P NO Erratic/No output
Instrument failure;
Control system failure
Seal failure
NO External rupture
IPCE-HCS-I&C -T NO External leak
IPCE-HCS-I&C -T NO Erratic/No output
IPCE-HCS-I&C -Q NO External leak
IPCE-HCS-I&C -Q NO Erratic/No output
Appendix B
Preventive
maintenance
Preventive
to Control system failure;
power;
system;
Actuator failure
Instrument failure;
Seal failure
Instrument failure;
Consequences as the ones listed for the "IPCE-HCS-Pipe
Loss of He coolant flow into bypass line;
Low temperature in BUs;
Loss of TBM breeding capability
LBP2
N/S
The valve has to be normally closed
for safety reasons (i.e.: to avoid bad
cooling of TBM in case of fault)
Reduced He coolant flow into Caps, Grid and BUs;
Impairing of capability to cool down Grid, Caps and BUs;
Consequences as for the "TBM-BU-Canister-CP - Partial
or complete plugging" could follow
LBB2
The valve has to be normally closed
for safety reasons (i.e.: to avoid bad
cooling of TBM in case of fault)
Preventive
maintenance
Test during
manufacturing &
assembly
Rupture"
LBP2
Preventive
maintenance
Preventive
maintenance
Preventive
maintenance
Preventive
maintenance
Preventive
maintenance
Preventive
maintenance
Reduced capability to control parameters
Redundant control systems
LBP2
LBP2
LBP2
LBP1
N/S
N/S
N/S
Page 25 of 47
Component
Op.
St.
Failure Mode
HCS-PipeShaft&Building
NO Loss
of
tightness
HCS-PipeShaft&Building
NO Rupture
Appendix B
Causes
Prev.Action on
Causes
Consequences
PIEs
Comment
Material defects;
Test during
manufacturing &
assembly
Loss of He coolant into Service Shaft and/or Vault;
Monitoring of amount of He LBO2
Release of Tritium contained in He coolant into Service contained in Service Shaft and
Shaft and/or Vault;
Vault atmosphere in order to
promptly detect leaks;
reduce the coolant released into
Service Shaft and/or Vault;
Isolation of HVAC;
recovery activities
Thermal insulation of piping let the
identification of the leak location
quite difficult
Material defects;
Test during
manufacturing &
assembly
Loss of He coolant into Service Shaft and/or Vault;
contained in Service Shaft and
Pressurization of Service Shaft and/or Vault;
Release of Tritium contained in He coolant into Service Vault atmosphere in order to
promptly detect leaks;
Shaft and/or Vault;
reduce the coolant released into
Service Shaft and/or Vault;
Isolation of HVAC;
recovery activities
Leak before break should advise
about the possible rupture, which
can be avoided by stopping the plant
operations;
MPa)
Emptying of the TBM cooling loop and loss of heat Plasma shutdown
removal capability;
In-vessel breaks and consequences as the ones described
for the "IPCE-HCS-Pipe - Rupture" could follow if
plasma is not promptly shutdown
In this case release of RadP_VV is
not towards the Port Cell but
towards the Service Shaft and the
Vault
Page 26 of 47
Component
Op.
St.
Failure Mode
HCS-PipeEU_HCPB-HeRoom
NO Loss
of
tightness
HCS-PipeEU_HCPB-HeRoom
NO Rupture
Causes
Prev.Action on
Causes
Consequences
PIEs
Material defects;
Test during
manufacturing &
assembly
Loss of He coolant into the Vault;
Release of Tritium contained in He coolant into the Vault; contained in the Vault atmosphere
in order to promptly detect leaks;
reduce the coolant released into the
Vault;
Isolation of HVAC;
recovery activities
Thermal insulation of piping let the
identification of the leak location
quite difficult
Material defects;
Test during
manufacturing &
assembly
Loss of He coolant into the Vault;
Pressurization of Vault;
Release of Tritium contained in He coolant into the Vault;
contained in the Vault atmosphere
Vault;
Isolation of HVAC;
recovery activities
Leak before break should advise
about the possible rupture, which
can be avoided by stopping the plant
operations;
MPa)
removal capability;
HCS-Recuperator
NO External leak
HCS-Recuperator
NO External rupture
HCS-Recuperator
NO Internal leak
Appendix B
Comment
Seal failure;
Weld failure
Material defects;
Weld failure;
Material defects and aging
Preventive
Consequences as the ones listed for the "HCS-Pipemaintenance
EU_HCPB-He-Room - Loss of leak tightness"
Test during
Consequences as the ones listed for the "HCS-Pipemanufacturing &
EU_HCPB-He-Room - Rupture"
assembly
Periodical test and Small bypass reducing amount of coolant flowing to TBM
inspection
In this case release of RadP_VV is
not towards the Port Cell but
towards the Service Shaft and the
Vault
LBO2
LBO1
N/S
Page 27 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
HCS-Recuperator
NO Internal rupture
Weld failure;
Periodical
Material defects and aging; inspection
Abnormal
operating
HCS-GasMixer
NO External leak
HCS-GasMixer
NO External rupture
Seal failure;
Weld failure
Material defects;
Weld failure;
Preventive
Consequences as the ones listed for the "HCS-Pipemaintenance
Test
during Consequences as the ones listed for the "HCS-Pipemanufacturing
& EU_HCPB-He-Room - Rupture"
assembly
HCS-HX
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
Loss of secondary water coolant into the Vault;
Apply detailed procedures (defined N/S
recovery activities
HCS-HX
NO External rupture
Material defects;
Weld failure;
Test
during Loss of secondary water coolant into the Vault;
manufacturing
& Increase of ORE for recovery actions
assembly
recovery activities
HCS-HX
NO Single pipe rupture Wearing due to vibration and Periodical test and Loss of He coolant into secondary cooling circuit;
Monitoring of secondary loop LBO3
corrosion
inspection;
Release of Tritium contained in He coolant into secondary parameters (flow rate, pressure and
Preventive
cooling circuit;
temperature);
maintenance;
Plasma shutdown;
Water
chemistry
Isolation of secondary loop;
control
Maintenance
of
HX
(pipe
plugging);
recovery activities
test
and Opening of a bypass reducing amount of coolant flowing Monitoring of TBM coolant inlet FB2
into TBM;
flow rate and temperature;
Loss of He coolant flow into TBM box;
Plasma shutdown
Increase of temperature in TBM box;
FSW structures;
follow
LBO2
LBO1
removal capability
Appendix B
Comment
For a short time PCS should
integrate He lost and avoid
aggravating damage inside TBM box
Page 28 of 47
Component
HCS-HX
Op.
St.
Failure Mode
NO Multiple
rupture
Causes
Prev.Action on
Causes
Consequences
PIEs
Comment
pipe Wearing due to corrosion, Periodical test and Loss of He coolant into secondary cooling circuit;
Plasma shutdown;
LBO3
vibration
and
pressure inspection;
Release of Tritium contained in He coolant into secondary Isolation of secondary loop;
transient
Preventive
cooling circuit;
Maintenance;
maintenance;
Water
chemistry
control
recovery activities
Release of Tritium contained in He coolant to Radioactivity
monitoring
secondary loop;
environment through cooling tower effluents
Radioactivity
monitoring
secondary loop area;
Procedural leakage’s control
of
of
removal capability;
Overheating of TBM;
Swelling of Ceramic Breeder and Be pebbles;
FSW structures
Ingress of water into TBM box cooling channels when the Isolation of TBM box
pressure in cooling circuit gets secondary cooling loop
pressure;
Be-water reactions if coolant channels inside the box lost
their integrity because thermo-mechanical stress;
H2 production;
Benefit of the TBM box isolation
has to be carefully evaluated because
it requires the use of other 2 isolation
valves, respectively in the inlet and
outlet legs of TBM, which, on their
part, can cause LOFA in case of
spurious closing
Ingress of He (i.e.: some coolant not yet discharged from
the loop and purge gas) and water (from the external
break in the HX) into VV;
Plasma disruption if it has not been actively or passively
(plasma poisoning due to armour material evaporation)
shutdown
The box break could occur also
without H2 explosion, only for the
effects of thermo mechanical stress
VV pressurisation;
Opening of bleed lines towards VVPSS when VV effective circuits in order to
pressure gets 90 kPa and opening of lines to drain tank quickly reduce temperature of
when p>110kPa;
Release of RadP_VV to secondary loop if VV pressure
overcomes secondary cooling loop pressure
Appendix B
Page 29 of 47
Component
HCS-HX (cntd)
Op.
St.
Failure Mode
NO Multiple
rupture
Causes
Prev.Action on
Causes
pipe
Consequences
PIEs
Comment
Aggravating consequences could occur in case of rupture Design VVPSS to treat over
in other water cooled PFCs due to disruption
pressurization
generated
by
mixture of He gas and steam
recovery activities
HCS-HX
NO Single
plugging
pipe Crud and impurities in the
He cooling loop;
Foreign object in the He
cooling loop
HCS-Filter
NO External leak
HCS-Filter
NO External rupture
HCS-Filter
NO Clogging
No consequences
N/S
Consequences as the ones listed for the "HCS-PipeEU_HCPB-He-Room - Loss of leak tightness"
Consequences as the ones listed for the "HCS-PipeEU_HCPB-He-Room - Rupture"
LBO2
Seal failure;
Weld failure
Material defects;
Weld failure;
Preventive
maintenance
Test during
manufacturing &
assembly
Crud and impurities in the
He cooling loop;
Foreign object in the He
cooling loop
Periodical test and Loss of He coolant flow;
inspection;
Increase of temperature in HCS loop;
Periodical replacement HCS loop over-pressurization;
Such a situation is planned by taking
into account that broken tubes will
be plugged during maintenance
LBO1
Monitoring of TBM coolant inlet FB2
Plasma shutdown
FSW structures;
follow
Appendix B
Page 30 of 47
Component
HCS-Circulator
Op.
St.
Failure Mode
NO Circulator stop
Causes
Prev.Action on
Causes
Loss of ancillary electr. Periodical
power;
inspection
Motor failure;
Blade rupture;
Bearing rupture
test
Consequences
and Loss of He coolant flow;
HCS loop over-pressurization;
PIEs
Comment
Plasma shutdown
FSW structures;
follow
HCS-Circulator
NO External leak
HCS-Circulator
NO External rupture
HCS-Heater
NO Fail to operate
HCS-V1
HCS-V1
Appendix B
Seal failure;
Weld failure
Material defects;
Weld failure;
Preventive
maintenance
Test during
manufacturing &
assembly
Resistor rupture;
Loss of ancillary electr.
power;
Preventive
maintenance
Preventive
power;
system;
Actuator failure
Consequences as the ones listed for the "HCS-PipeEU_HCPB-He-Room - Rupture"
LBO2
LBO1
Loss of capability to control temperature of He inlet to
TBM;
N/S
TBM;
LBO2
N/S
The valve has been considered
normally closed for safety reasons
(i.e.: to avoid bad cooling of TBM in
case of fault)
Page 31 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
Comment
HCS-V1
NO Valve
fail
operate:
completely opened
Preventive
maintenance
Partial loss of He coolant flow into TBM box;
Plasma shutdown
FSW structures;
follow
HCS-V2
Preventive
maintenance
Loss of secondary water coolant into the Vault;
recovery activities
It's assumed that the valve is inside
Vault. Milder consequences in terms
of ORE if the valve is in the
secondary loop area
HCS-V2
NO Valve
fail
operate:
completely closed
Preventive
maintenance
Loss of Heat Sink to HCS;
Monitoring of secondary loop flow HB1
rate;
Monitoring of TBM coolant inlet
Plasma shutdown
normally open for safety reasons
(i.e.: to avoid bad cooling of TBM in
case of fault)
FSW structures;
follow
HCS-V4
HCS-V4
NO Valve fail to close
HCS-V4
NO Valve
fail
operate:
completely closed
Appendix B
power;
system;
Actuator failure
Preventive
maintenance
Preventive
maintenance
TBM;
Preventive
maintenance
TBM;
LBO2
N/S
normally open
N/S
normally closed
Page 32 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
HCS-V5
Preventive
maintenance
Preventive
power;
system;
Actuator failure
HCS-V5
NO Valve fail to close
HCS-V5
NO Valve
fail
operate:
completely closed
Preventive
maintenance
HCS-V5
NO Valve
fail
to Control system failure
operate:
stuck
completely closed
(CCF with "HCSV4")
Periodical
inspection
Consequences
TBM;
TBM;
test
and Loss of He coolant flow;
PIEs
Comment
LBO2
N/S
normally open
N/S
normally closed
Plasma shutdown
FSW structures;
follow
HCS-V6
HCS-V6
NO Valve
closing
HCS-V7
Appendix B
spurious Control system failure;
Human error
Preventive
Consequences as the ones listed for the "HCS-PipeLBO2
maintenance
Set valve interlock Loss of He coolant flow into TBM box;
during operations
Plasma shutdown
FSW structures;
follow
Preventive
maintenance
LBO2
Page 33 of 47
Component
Op.
St.
Failure Mode
Causes
HCS-V7
NO Valve
closing
HCS-V8
HCS-V8
NO Valve
opening
PCS-StorageT;
PCS-BufferT;
PCS-SourceT
PCS-Compressor
NO External leak
Seal failure;
Weld failure
NO External leak
Seal failure
PCS-Compressor
NO Fail to operate
PCS-V1
Appendix B
Human error
Human error
Prev.Action on
Causes
Consequences
PIEs
Comment
Set valve interlock Loss of He coolant flow into TBM box;
during operations
Plasma shutdown
FSW structures;
follow
Preventive
maintenance
Set valve interlock Opening of a bypass reducing amount of coolant flowing Monitoring of TBM coolant inlet FB1
during operations
into TBM;
Plasma shutdown
FSW structures;
follow
Preventive
maintenance
Preventive
maintenance
Preventive
power;
Actuator failure
Preventive
maintenance
LBO2
Loss of capability to transfer He coolant from buffer tank Monitoring of Source tank N/S
to source tank;
pressure;
Loss of capability to re-pressurize HCS loop before Monitoring of HCS pressure and
burning of plasma
flow rate;
Stop plasma operations
Credit has given to the capability in
detecting the failure and prevent
burning of plasma
LBO2
Page 34 of 47
Component
PCS-V1
Op.
St.
Failure Mode
NO Valve
opening
Causes
Human error
Prev.Action on
Causes
Consequences
PIEs
Comment
Set valve interlock Loss of He coolant from HCS and PCS;
Monitoring of HCS pressure and LBO1
during operations
Release of Tritium contained in He coolant into flow rate;
subsystem located outside Vault;
Isolation of HCS and PCS by
Possible release to environment through external loop closing all valves;
leaks;
recovery activities
removal capability;
PCS-V2
PCS-V2
NO Valve fail to open Control system failure;
on demand
power;
system;
Actuator failure
PCS-V3
PCS-V3;
PCS-V9;
PCS-V10
on demand
power;
system;
Actuator failure
PCS-V6
on demand
power;
system;
Actuator failure
Appendix B
Preventive
maintenance
Preventive
maintenance
Loss of capability to control pressure in HCS loop;
Mechanical stress on TBM box and HCS loop;
Possible loss of leak tightness in HCS and/or TBM box
Preventive
maintenance
Preventive
maintenance
Loss of capability to transfer He coolant from buffer tank Monitoring of Source tank N/S
to source tank;
pressure;
Loss of capability to re-pressurize HCS loop before Monitoring of HCS pressure and
burning of plasma
flow rate;
Preventive
maintenance
Loss of capability to re-pressurize HCS loop before Monitoring of HCS pressure and LBV2
burning of plasma;
flow rate;
Reduced capability to cool down TBM;
FSW structures in case plasma burning is not stopped;
follow
LBO2
LBO2
Credit has given to the capability in
detecting the failure and prevent
burning of plasma
Page 35 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
PCS-V4;
PCS-V5;
PCS-V6;
PCS-V7;
PCS-V8;
PCS-V9;
PCS-V10;
PCS-V11
Preventive
maintenance
LBO2
PCS-V11
on demand
power;
system;
Actuator failure
Preventive
maintenance
Loss of capability to control pressure in HCS loop;
Mechanical stress on TBM box and HCS loop;
Possible loss of leak tightness in HCS and/or TBM box
LBO2
PCS-Pipe
NO Loss
of
tightness
Preventive
maintenance
LBO2
Preventive
maintenance
Consequences as the ones listed for the "HCS-Pipe- Isolation of water separator
LBO2
CPS-Water
Separator-1
leak Seal failure;
Weld failure;
NO External leak from Seal failure;
the gas stream Weld failure
volume
Appendix B
Comment
Leaks from valves are more probable
then leaks from welds in case of over
pressurization,
therefore,
in
assigning the PIE has been given
more credit to the possibility of a
leak out vessel then a leak in-vessel
Page 36 of 47
Component
CPS-Water
Separator-1
Op.
St.
Failure Mode
Causes
the water sump
Weld failure
Prev.Action on
Causes
Preventive
maintenance
Consequences
Loss of tritiated water into the vault;
Vault contamination;
Tritium monitoring;
Isolation of water separator;
Drainage;
Surface decontamination
PIEs
LBO2
Loss of He coolant into the Vault if the leak from the Monitoring of amount of He
sump is not repaired before its emptying or the separator contained in the Vault atmosphere
is not isolated;
Release of Tritium contained in He coolant into the Vault; Isolation of broken circuits to
Vault;
Isolation of HVAC;
recovery activities
Controlled access into HCS loop N/S
Reduced capability to detritiate HCS;
areas;
Increase of tritium permeation from HCS to building;
Tritium monitoring
Increase of ORE;
Reduced capability to remove possible high content of
water from HCS;
Increase of risks associated to TBM because possible Bewater reactions and H2 production/explosion could occur
in case of internal breaks in TBM box
NO Fail to operate
Ancillary system failure
CPS-Heater-2a
NO External leak
CPS-Heater-2a
NO Fail to operate
Seal failure;
Preventive
Weld failure
maintenance
Resistor rupture;
power;
Reduced capability to oxidize H and T contained in the Maintenance;
N/S
He stream;
Controlled access into HCS loop
Loss of CPS effectiveness;
areas;
Increase of tritium accumulated in HCS;
Tritium monitoring
Increase of ORE
CPS-Oxidezer-3
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
If the initiator is not promptly
detected, in this case, the hazard
related to tritium released from HCS
to the building could be one of the
highest between the hazards related
to the possible releases determined
by the other events grouped in the
LBO2 PIE
That because beyond the tritium
currently contained in the gaseous
stream, the tritium accumulated in
the separator after several hours of
operations could be released in the
vault. Furthermore, it is in the more
hazardous HTO form
CPS-Water
Separator-1
Appendix B
Preventive
maintenance
Comment
LBO2
Page 37 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
CPS-Oxidezer-3
NO Oxidizer
deterioration
Aging;
Dirtying
Periodical replacement Reduced capability to oxidize H and T contained in the Maintenance;
N/S
He stream;
areas;
Tritium monitoring
Increase of ORE
CPS-Cooler-4
NO Inner pipe leak
Aging;
Corrosion
Periodical test and Loss of He coolant into secondary cooling circuit;
Isolation of secondary loop;
LBO3
inspection;
Release of Tritium contained in He coolant into secondary Maintenance;
Preventive
cooling circuit;
maintenance;
Water
chemistry
recovery activities
control
CPS-Cooler-4
NO Fail to operate
Pump failure in water Preventive
maintenance
cooling loop;
power;
CPS-Blower-5
NO Fail to operate on Control system failure;
Preventive
demand
power;
Actuator failure
CPS-Adsorber6a/6b
CPS-Adsorber6a/6b
NO External leak
CPS-Adsorber6a/6b
NO Spurious activation Control system failure;
of heater
Human error
Set interlocks during Heating up of "CPS-Adsorber-6a/6b";
Isolation of CPS from HCS;
N/S
operations
Release of water content and gaseous impurities to outlet Isolation of failed Adsorber;
stream;
Activation of redundant Adsorber
CPS-Heater-2b
NO External leak
Preventive
maintenance
NO Molecular
deterioration
Appendix B
Seal failure;
Weld failure
bed Aging;
Dirtying
Seal failure;
Weld failure
Comment
The He lost from the CPS and,
consequentially, from the HCS
circuit should be automatically
replaced by the PCS
N/S
Maintenance;
Heating up of "CPS-Adsorber-6a/6b";
Release of water content and gaseous impurities to outlet Controlled access into HCS loop
areas;
stream;
Tritium monitoring
Increase of ORE
Reduced flow in CPS;
Reduced CPS effectiveness;
Maintenance;
N/S
areas;
Tritium monitoring
Preventive
maintenance
Periodical replacement Loss of capability to trap water content and impurities Isolation of deteriorated Adsorber; N/S
from the gas stream;
LBO2
Page 38 of 47
Component
CPS-Heater-2b
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
PIEs
Preventive
power
NO External leak
Seal failure;
Preventive
Weld failure
maintenance
NO Fail to operate:
Preventive
addition of H2 low Ancillary system failure
maintenance
with respect to
design parameters
Return pure He into the main cooling loop at room
N/S
temperature;
Disturbance in HCS parameters
Loss of capability to fix tritium in HT;
areas;
Increase of ORE
Tritium monitoring
CPS-HeMakeUp
NO Fail to operate:
addition of H2O
Ancillary system failure
low with respect to
design parameters
Loss of capability to oxidize internal TBM and HCS Controlled access into HCS loop N/S
surfaces in order to reduce tritium permeation;
areas;
Tritium monitoring
Increase of ORE
CPS-Valves
CPS-Valves
or to remain open
CPS-Pipe
NO Loss
of
tightness
CPS-ReliefT-7
CPS-HeMakeUp
TES-PipeShaft&Building
NO Fail to operate
Consequences
Preventive
maintenance
Preventive
maintenance
Preventive
Loss of He coolant flow in CPS;
Maintenance;
N/S
Loss of ancillary electr. maintenance;
power;
Set valve interlock Increase of tritium accumulated in HCS;
areas;
Fault in pneumatic supply during operations
Tritium monitoring
system;
Increase of ORE
Actuator failure;
Human error
leak Seal failure;
Preventive
Weld failure;
maintenance
NO Loss
of
Test
during Loss of purge gas into secondary containment;
Monitoring and evacuation of N/S
tightness in internal Material defects;
manufacturing
& Possible tritium permeation from TES secondary guard pipe volume in case of leaks
from process line;
tube
Abnormal
operating assembly
containment to building;
recovery activities
Appendix B
Comment
The tank could contain high amount
of impurities
Valves here considered are the ones
open during NO
Identification of leak location could
be quite difficult if guard pipe
partitions are not foreseen along the
line
Page 39 of 47
Component
Op.
St.
Failure Mode
Causes
Consequences
PIEs
TES-PipeShaft&Building
NO Rupture
TES-Pipe-GB
NO Loss
of
tightness
TES-V3;
TES-V4;
TES-V5;
TES-V6
Preventive
maintenance
Loss of purge gas into secondary containment;
Isolation of TES and TBM box to TBL2
Possible tritium permeation from TES secondary reduce the amount of gas released;
containment to building
Glove Box detritiation
TES-Valves
Preventive
maintenance
TES-V3
Preventive
or to remain open Loss of ancillary electr. maintenance
power;
system;
Actuator failure;
Human error
Appendix B
Prev.Action on
Causes
Comment
Protect piping trays Loss of purge gas double containments;
Isolation of TES and TBM box to TBP2
from impact of heavy Release of Tritium contained in TBM-BU and TES circuit reduce the amount of gas released;
loads
into building;
Isolation of HVAC;
Increase of ORE
Atmosphere detritiation;
Controlled
access
into
contaminated areas;
recovery activities
Test
during Loss of purge gas into secondary containment;
Material defects;
manufacturing
& Possible tritium permeation from TES secondary reduce the amount of gas released;
Abnormal
operating assembly
(flow
rate,
pressure
and
temperature);
Stop TES compressors
Pressurization of TBM box in volumes fulfilled by purge
gas;
Port Cell;
capability
in
stopping
the
compressors;
released
Page 40 of 47
Component
TES-V4
Op.
St.
Failure Mode
or to remain open
Causes
Prev.Action on
Causes
Preventive
power;
system;
Actuator failure;
Human error
NO Valve spurious
opening
Human error
TES-Valves
or to remain open
Preventive
power;
system;
Actuator failure;
Human error
NO Inner pipe leak
Appendix B
Aging;
Corrosion
PIEs
Comment
(flow
rate,
pressure
and
temperature);
Set valve interlock Opening of a bypass strongly reducing the amount of Monitoring of TES parameters N/S
purge gas flowing into TBM;
(flow
rate,
pressure
and
during operations
temperature);
Maintenance
Increase of tritium permeation into HCS;
TES-V5;
TES-V6
TES-Cooler-1
Consequences
Periodical test and
inspection;
Preventive
maintenance;
Water chemistry
control
Ingress of water into TES process line;
Increase of amount of water to be detritiated;
(flow
rate,
pressure
and
temperature);
open during NO in the TES main
loop
Maintenance;
N/S
recovery activities
Page 41 of 47
Component
TES-Cooler-1
Op.
St.
Failure Mode
NO Fail to operate
Causes
Pump failure in water
cooling loop;
power;
Prev.Action on
Causes
Preventive
maintenance
Consequences
PIEs
Heating up of "TES-ColdTrap-4" and of "TES- Monitoring of TES parameters N/S
LTAdsorber-6 a/b";
(flow
rate,
pressure
and
Release of water content and gaseous impurities to outlet temperature);
stream;
Loss of TES effectiveness;
Increase of Tritium concentration in TES;
Port Cell;
Increase of ORE
Comment
released
Reduced capability to remove possible high content of Plasma shutdown
water from He purge gas stream;
Increase of risks associated to TBM because, in case a
leak in water cooler exists, Be-water reaction and H2
production occur;
Possible TBM box collapse due to thermo-mechanical
stress induced by heat generated in the diverging Bewater reaction;
TES-Filter-2
NO External leak
Seal failure;
Weld failure;
Incorrect installation
TES-Filter-2
NO Clogging
Excessive particulate from Periodical test and
TBM and/or from TES inspection;
(flow
rate,
pressure
and
circuit
Periodical replacement Increase of Tritium concentration in TBM;
temperature);
Pressurization of TBM box in volumes fulfilled by purge Filter replacement
gas;
Port Cell;
TES-IonChamber3a/b
NO External leak
Seal failure;
Weld failure;
Test during
manufacturing &
assembly
TES-IonChamber3a/b
NO Erratic/No output
Instrument failure;
Periodical
inspection
Appendix B
Test during
manufacturing &
assembly
test
released
and Erratic measurement of amount of tritium flowing through
the two sections of TES;
N/S
Page 42 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
Comment
TES-ColdTrap-4
the gas stream Weld failure;
volume
Test during
manufacturing &
assembly
TES-ColdTrap-4
the water sump
Weld failure;
Test during
manufacturing &
assembly
Loss of tritiated water into GB when the recovery of Glove Box detritiation
iced/liquefied water will start by heating and draining into
a water collector;
Possible tritium permeation from TES secondary
TES-ColdTrap-4
NO Fail to operate
Preventive
Reduced capability to detritiate He purge gas;
maintenance;
Increase of tritium permeation from TES process line to (flow
rate,
pressure
and
Set interlocks during Port Cell;
temperature);
operations
Increase of ORE
released
Reduced capability to remove possible high content of Plasma shutdown
water from He purge gas stream;
Increase of risks associated to TBM because, in case a
leak in water cooler exists, Be-water reaction and H2
production occur;
Possible TBM box collapse due to thermo-mechanical
stress induced by heat generated in the diverging Bewater reaction;
The failure to operate here
considered could be due both to
"LN2 loop - fail to operate" or to
"Heating coil - spurious power on";
Some water can be trapped in the
LTAdsorber but both because the
capability to ice water is lower and
because the fault could be a common
cause (i.e.: fault in LN2 supply),
credit can not be given to the
capability of the adsorber to ice the
water
Frequent recovery of Loss of flow in TES;
frozen water
(flow
rate,
pressure
and
temperature);
Pressurization of TBM box in volumes fulfilled by purge
gas;
Port Cell;
Likelihood of this event is
particularly high in case a leak in
water cooler exists;
capability
in
stopping
the
compressors;
released
TES-ColdTrap-4
NO Plugging
Appendix B
Ancillary system failure;
Human error
Ice formation
TBL2
Page 43 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
TES-Recuperator-5 NO External leak
Seal failure;
Weld failure;
Test during
manufacturing &
assembly
TES-Recuperator-5 NO Internal rupture
Weld failure;
Material defects and aging
Periodical
inspection
TES-LTAdsorber-6 NO External leak
a/b
Seal failure;
Weld failure
Preventive
maintenance
TES-LTAdsorber-6 NO Molecular
a/b
deterioration
bed Aging;
Dirtying
TES-LTAdsorber-6 NO Fail to operate Control system failure;
a/b
during
operating Human error
phase
(i.e.:
detritiation
and
cleaning of gaseous
stream)
PIEs
Comment
and Opening of a bypass which excludes part of the system in Monitoring of TES parameters N/S
treating the purge gas stream;
(flow
rate,
pressure
and
Reduced TES effectiveness in detritiate and purify He temperature);
purge gas;
Maintenance
Periodical replacement Loss of capability to trap water content and impurities Isolation of deteriorated Adsorber; N/S
from the gas stream;
Port Cell;
Increase of ORE
Set interlocks during
operations
TES-LTAdsorber-6 NO Fail to operate Loss of ancillary electr. Preventive
a/b
during
power;
maintenance
downloading and Control system failure
regeneration phases
(e.g.: Heating coil fail to operate)
Appendix B
test
Consequences
Heating up of "TES-LTAdsorber-6 a/b";
Isolation of failed Adsorber;
N/S
Release of water content and gaseous impurities to outlet Activation of redundant Adsorber
stream;
Port Cell;
Increase of ORE
The failure to operate here
considered could be due both to
"LN2 loop - fail to operate" or to
"Heating coil - spurious power on"
Loss of capability to regenerate Adsorber;
Maintenance;
N/S
Loss of TES effectiveness if the fault continue till the Controlled access into HCS loop
back-up Adsorber is saturated;
areas;
Tritium monitoring
Increase of ORE
Page 44 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
Consequences
PIEs
TES-LTAdsorber-6 NO Filter clogging
a/b
Excessive particulate from Periodical test and Loss of flow in TES;
Adsorber bed;
inspection;
(flow
rate,
pressure
and
Ice formation
Periodical
temperature);
replacement;
Frequent recovery of Pressurization of TBM box in volumes fulfilled by purge Isolation of failed Adsorber;
frozen water
gas;
Port Cell;
TES-Heater-7
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TES-Heater-7
NO Fail to operate
power
Preventive
maintenance
Returning of He purge gas stream into TBM at very low
temperature (-140 °C);
Thermo-mechanical stress on TBM structures;
Impairing of TBM box structural integrity
TES-Compressor-8 NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TES-Compressor-8 NO Fail to operate
Loss of ancillary electr. Preventive
power;
maintenance
Actuator failure;
reduce the amount of gas released;
Increase of ORE
(flow
rate,
pressure
and
temperature);
areas;
Tritium monitoring
Preventive
maintenance
Loss of capability to fix tritium in HT;
Increase of tritium permeation from TES process line to areas;
Port Cell;
Tritium monitoring
Increase of ORE
TES-HeMakeUp-9 NO Fail to operate: low Control system failure;
or no addition of Ancillary system failure
He in case refilling
is
required
to
compensate leaks
from the loop
Preventive
maintenance
Reduced mass flow rate of He stream passing through Controlled access into HCS loop N/S
TBM;
areas;
Reduced capability to remove tritium from TBM box;
Tritium monitoring
Increase of ORE
capability
in
stopping
the
compressors;
released
N/S
TES-HeMakeUp-9 NO Fail to operate: Control system failure;
addition of H2 low Ancillary system failure
with respect to
design parameters
Appendix B
Comment
Consequences here described are
true if the amount of He missing is
significant for the process
Page 45 of 47
Component
Op.
St.
Failure Mode
TES-Water
Collector-10
NO External leak
TES-Blower-11a
NO External leak
Causes
Prev.Action on
Causes
Consequences
Seal failure;
Weld failure;
Seal failure;
Weld failure
Test during
manufacturing &
assembly
Preventive
maintenance
Loss of tritiated water into Glove Box;
Stop Adsorber re-generation;
Isolation
of
Adsorber
regeneration phase;
PIEs
TBL2
TBL2
in
TES-Blower-11a
NO Fail to operate
power;
Actuator failure;
Preventive
maintenance
Maintenance;
N/S
areas;
Tritium monitoring
Increase of ORE
TES-ReliefT-12
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
of
Adsorber
Possible tritium permeation from TES secondary Isolation
regeneration phase;
TBL2
Possible tritium permeation from TES secondary Glove Box detritiation
Loss of capability to evacuate the relief tank and, Maintenance;
N/S
therefore, to re-generate the saturated Adsorber;
Loss of TES effectiveness if the fault continue till the areas;
Tritium monitoring
Increase of ORE
TES-Blower-11b
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TES-Blower-11b
NO Fail to operate
power;
Actuator failure;
Preventive
maintenance
TES-Diffusor-13
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TES-Diffusor-13
NO Membrane rupture Aging;
Material defects;
Overpressure
Appendix B
Possible tritium permeation from TES secondary Glove Box detritiation
Periodical replacement Loss of hot gas in secondary side of Diffuser;
Equalization of pressures in the two loops of the two Isolation
of
Adsorber
Diffuser sides;
regeneration phase;
Heating up of diffuser secondary side loop;
Glove Box detritiation;
Mobilization in the two loops of the tritium stored in Maintenance
getter beds;
Loss of TES effectiveness if the fault continue till the
Increase of ORE
Comment
TBL2
in
TBL2
N/S
in
Page 46 of 47
Component
Op.
St.
Failure Mode
Causes
Prev.Action on
Causes
TES-GetterBed-14 NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TESNO External leak
HeBufferVessel-15
Seal failure;
Weld failure
Preventive
maintenance
TES-Blower-11c
NO External leak
Seal failure;
Weld failure
Preventive
maintenance
TES-Blower-11c
NO Fail to operate
power;
Actuator failure;
Preventive
maintenance
TES-Valves
or to remain open Loss of ancillary electr.
power;
system;
Actuator failure;
Human error
Appendix B
Preventive
maintenance
Consequences
PIEs
Comment
TBL2
Maintenance
TBL2
Maintenance
TBL2
Loss of flow in Diffuser secondary side;
Maintenance;
N/S
Loss of capability to evacuate hydrogen isotopes during Controlled access into HCS loop
re-generation of the saturated Adsorber;
areas;
Loss of TES effectiveness if the fault continue till the Tritium monitoring
Increase of ORE
Maintenance;
N/S
areas;
Tritium monitoring
Increase of ORE
open during Adsorber Regeneration
Page 47 of 47
Appendix C
PIEs related to failures on HCPB TBM systems and elementary contributors
Op.
PIEs
St.
NO FB1
Component Code
Component Description
Failure Mode
HCS-Circulator
HCS-V5
HCS - Circulator
HCS - Valve 5 to control the economizer secondary stage inlet. It works together with Valve 4
HCS-V6
HCS - Valve 6 (gate valve) used only to close the TBM inlet line for TBM removal in order to keep the He inside the Valve spurious closing
HCS. It is closed together with Valve 7
HCS - Valve 7 (gate valve) used only to close the TBM outlet line for TBM removal in order to keep the He inside the Valve spurious closing
HCS - Valve 8 (gate valve) to bypass the whole TBM piping through the ITER building including the TBM. It is open Valve spurious opening
when Valves 6 and 7 are closed
HCS-V7
HCS-V8
Circulator stop
Valve fail to operate: stuck completely closed (CCF with "HCS-V4")
NO
FB2
HCS-Recuperator
HCS-Filter
HCS-V1
HCS - Dust Filter
Internal rupture
Clogging
Valve fail to operate: stuck completely opened
NO
HB1
HCS-V2
HCS - Valve 2 to control the secondary circuit of the cooler to have influence on the circulator inlet temperature
Valve fail to operate: stuck completely closed
NO
LBB1
TBM-BottPM3-Welds
Rupture
TBM - Bottom Plate Manifold 3 - Welds sealing between He coolant inlet to BU (or He coolant out from Grid & Caps) Rupture
and outlet purge gas
TBM - Bottom Plate Manifold 3 - Welds located in the internal ship zone, to seal pipes with He coolant outlet from BU Rupture
to the BottPM. The welds separate the BU He coolant outlet from the purge gas outlet
Appendix C
Page 1 of 9
Op.
PIEs
St.
NO LBB2
NO
LBO1
Component Code
Failure Mode
TBM-Grid
TBM-Grid-CoolCh
TBM-Grid-CapWeld
TBM-Grid-FSWWeld
TBM-BU-Canister-CBP
TBM-BU-Canister-CBP
TBM-BU-Canister-BeP
TBM-BU-Canister-BeP
TBM-BU-Canister-CP
TBM-BU-Canister-Wrap
TBM-BottPM3-Welds
TBM - Grid
Local deformation
TBM - Grid - Cooling Channel
Partial or complete plugging
TBM - Grid - Welds to assemble the Grid to Caps
Rupture
TBM - Grid - Welds to assemble the Grid to FSW
Rupture
Abnormal swelling of pebbles
Generation of empty spaces inside the canister
Abnormal swelling of pebbles
Generation of empty spaces inside the canister
TBM - BU - Canister - Cooling Plates
TBM - BU - Canister - Assembling Wrap
Rupture
Loss of leak tightness
TBM - Bottom Plate Manifold 3 - Welds sealing between He coolant inlet to BU (or He coolant out from Grid & Caps) Loss of leak tightness
and outlet purge gas
TBM - Bottom Plate Manifold 3 - Welds to fix the Ships to the BottPM. They seal between the He coolant inlet to BUs Loss of leak tightness
and the He coolant outlet from BUs
TBM - Bottom Plate Manifold 3 - Welds to fix the Ships to the BottPM. They seal between the He coolant inlet to BUs Rupture
and the He coolant outlet from BUs
TBM-BottPM3-BUoutWelds TBM - Bottom Plate Manifold 3 - Welds located in the internal ship zone, to seal pipes with He coolant outlet from BU Loss of leak tightness
to the BottPM. The welds separate the BU He coolant outlet from the purge gas outlet
TBM-BottPM2-Welds
TBM - Bottom Plate Manifold 2 - Welds sealing between He coolant inlet to Grids & Caps (or He coolant outlet from Loss of leak tightness
FSW) and He coolant inlet to BU (or He coolant out from Grid & Caps)
TBM-BottPM2-Welds
TBM - Bottom Plate Manifold 2 - Welds sealing between He coolant inlet to Grids & Caps (or He coolant outlet from Rupture
FSW) and He coolant inlet to BU (or He coolant out from Grid & Caps)
TBM-BottPM1-OutCollector TBM - Bottom Plate Manifold 1 - Outlet Collector. Welds of the collector seal between He coolant inlet to FSW and He Loss of weld leak tightness
coolant outlet from BUs
TBM-Ship-SepP_In/OutWelds TBM - Separation plate inlet outlet in ship. Welds sealing He coolant inlet to TBM-FSW from He coolant outlet from Loss of leak tightness
BUs
IPCE-HCS-V3
IPCE - part of HCS inside IPC - Valve 3 is a mass control valve to share the flow between the outlet and the bypass lines Valve fail to operate: stuck completely opened
from TBM.
Helium Cooling System - He coolant Piping routing in the Vertical Shaft and TCWS Vault to get the HCS area Rupture
(EU_HCPB-He-Room)
Helium Cooling System - He coolant Piping routing in the HCS area (EU_HCPB-He-Room)
Rupture
HCS-Recuperator
HCS-GasMixer
HCS - Gas mixer to join the Helium flow of the Recuperator primary outlet line and the circulator bypass line
External rupture
External rupture
HCS-Filter
HCS-Circulator
PCS-V1
HCS - Dust Filter
HCS - Circulator
External rupture
External rupture
Valve spurious opening
Appendix C
Page 2 of 9
Op.
PIEs
St.
NO LBO2
Component Code
HCS-Recuperator
HCS-GasMixer
HCS-Filter
HCS-Circulator
HCS-V1
HCS-V4
HCS-V5
HCS-V6
HCS-V7
HCS-V8
PCS-StorageT
PCS-BufferT
PCS-SourceT
PCS-Compressor
PCS-V1
PCS-V2
PCS-V2
PCS-V3
PCS-V4
PCS-V5
PCS-V6
PCS-V7
PCS-V8
PCS-V9
PCS-V10
PCS-V11
PCS-V11
PCS-Pipe
CPS-Heater-2a
CPS-Oxidezer-3
CPS-Adsorber-6a/6b
Appendix C
Failure Mode
Helium Cooling System - He coolant Piping routing in the Vertical Shaft and TCWS Vault to get the HCS area Loss of leak tightness
(EU_HCPB-He-Room)
Helium Cooling System - He coolant Piping routing in the HCS area (EU_HCPB-He-Room)
HCS - Gas mixer to join the Helium flow of the Recuperator primary outlet line and the circulator bypass line
External leak
External leak
HCS - Dust Filter
External leak
HCS - Circulator
External leak
Valve external leak
HCS - Valve 4 to control the economizer bypass. It works together with Valve 5
Valve external leak
Valve external leak
HCS - Valve 6 (gate valve) used only to close the TBM inlet line for TBM removal in order to keep the He inside the Valve external leak
HCS - Valve 7 (gate valve) used only to close the TBM outlet line for TBM removal in order to keep the He inside the Valve external leak
HCS - Valve 8 (gate valve) to bypass the whole TBM piping through the ITER building including the TBM. It is open Valve external leak
when Valves 6 and 7 are closed
PCS - Storage Tank
External leak
PCS - Buffer Tank
External leak
PCS - Source Tank
External leak
External leak
Valve external leak
Valve external leak
Valve fail to open on demand
Valve external leak
PCS - Valve 4 connecting Storage tank to circulator downstream line
Valve external leak
PCS - Valve 5 connecting Storage tank to circulator upstream line
Valve external leak
Valve external leak
PCS - Valve 7 connecting Source tank to circulator upstream line
Valve external leak
PCS - Valve 8 in the circulator bypass line
Valve external leak
Valve external leak
Valve external leak
Valve external leak
PCS - Piping in the Pressure Control System
External leak from the gas stream volume
External leak from the water sump
CPS - Electrical Heater (2a) to increase the T of the He stream to 450° C, i. e. to the operation temperature of the External leak
catalytic oxidizer
External leak
External leak
Page 3 of 9
Op.
St.
PIEs
Component Code
Failure Mode
(cntd)
CPS-Heater-2b
CPS-ReliefT-7
CPS-Valves
CPS-Pipe
CPS - Electrical Heater (2b) to warm up the gas coming from the adsorbers (No. 6a/b)
CPS - Relief Tank
PCS - Piping in the Coolant Purification System
External leak
External leak
Valve external leak
NO
LBO3
HCS-HX
HCS-HX
CPS-Cooler-4
Single pipe rupture
Multiple pipe rupture
Inner pipe leak
NO
LBP1
IPCE-HCS-Pipe
IPCE - part of Helium Cooling System inside Inter-space and Port Cell (IPC) - He coolant Piping (Inlet/Outlet/Bypass) Rupture
IPCE-HCS-GasMixer
IPCE - part of HCS inside IPC - Gas mixer to join the Helium flow of the outlet line and the bypass line (T difference External rupture
between the two gas flows can be up to 200 °C)
IPCE-HCS-Pipe
IPCE - part of Helium Cooling System inside Inter-space and Port Cell (IPC) - He coolant Piping (Inlet/Outlet/Bypass) Loss of leak tightness
IPCE-HCS-V3
IPCE-HCS-I&C -P
IPCE-HCS-I&C -T
IPCE - part of HCS inside IPC - Valve 3 is a mass control valve to share the flow between the outlet and the bypass lines Valve external leak
from TBM.
IPCE - part of HCS inside IPC - Gas mixer to join the Helium flow of the outlet line and the bypass line (T difference External leak
between the two gas flows can be up to 200 °C)
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Pressures
External leak
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Temperatures
External leak
IPCE-HCS-I&C -Q
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Flow Rates
NO
LBP2
IPCE-HCS-GasMixer
NO
LBV1
External leak
TBM-FSW
TBM-FSW
TBM-FSW
TBM-FSW-CoolCh
TBM-Cap
TBM-Cap
TBM-Cap
TBM-Cap-CoolCh
TBM-BottPM1-Welds
Rupture
Plate deformation
Break in internal hipping joint
TBM - First Side Wall - Cooling Channel
TBM - Caps
Rupture
TBM - Caps
Plate deformation
TBM - Caps
Break in internal hipping joint
TBM - Caps - Cooling Channels
TBM - Bottom Plate Manifold 1 - Welds sealing between He coolant inlet to FSW and He coolant inlet to Grid & Caps Loss of leak tightness
(or He coolant outlet from FSW)
TBM-BottPM1-Welds
TBM - Bottom Plate Manifold 1 - Welds sealing between He coolant inlet to FSW and He coolant inlet to Grid & Caps Rupture
(or He coolant outlet from FSW)
TBM-BottPM1-OutCollector TBM - Bottom Plate Manifold 1 - Outlet Collector. Welds of the collector seal between He coolant inlet to FSW and He Rupture
coolant outlet from BUs
TBM-Ship-SepP_In/OutWelds TBM - Separation plate inlet outlet in ship. Welds sealing He coolant inlet to TBM-FSW from He coolant outlet from Rupture
BUs
TBM-BPM-Welds
TBM - Back Plate Manifold - Welds sealing between He coolant inlet to FSW and VV
Rupture
Appendix C
Page 4 of 9
Op.
St.
NO
PIEs
LBV2
Component Code
TBM-FSW-CapWeld-Rear
Failure Mode
TBM-PP-IS-HeCoolFT
PCS-V6
TBM - FSW - Welds to assemble the Caps with the FSW - small part of the welds sealing the rear part of the TBM Loss of leak tightness
volume hosting He coolant manifolds
TBM - Back Plate Manifold - Welds sealing between He coolant inlet to FSW and VV
TBM - Port Plug - Interface System - Attachment Plate - Shear Keys: to fix TBM box to PP and to cope with forces and Rupture
torques in the toroidal - poloidal plane
Loss of leak tightness of weld located in VV
TBM-BPM-Welds
TBM-PP-IS-AttP-ShearKeys
NO
LFP2
IPCE-PP-Frame&ShieldWCoolPipes
IPCE - Water cooling Pipes (Inlet/Outlet) to cool down the frame and shielding parts of the Port Plug. Water from the Loss of leak tightness
FW/BLK cooling circuit
NO
LFV2
PP-Frame-WCoolCh
PP-Shield-WCoolCh
Port Plug - Frame - Water Cooling Channels: Front and lateral parts of the PP
Port Plug - Shield - Water Cooling Channels: Shielding part of the PP
NO
LVP2
IPCE-PP-Rear-WCoolPipes
IPCE - Water cooling Pipes (Inlet/Outlet) to cool down the Rear part and flange of the Port Plug. Water from the VV Loss of leak tightness
cooling circuit
NO
LVV2
TBM-PP-IS-ElBlock
TBM - Port Plug - Interface System - Electrical Strap Blocks to protect the system from the plasma halo currents and Loss of electrical contact
their large EM forces
Port Plug - Rear - Water Cooling Channels: Rear part of the PP and PP flange to VV
PP-Rear-WCoolCh
Appendix C
Page 5 of 9
Op.
PIEs
St.
NO TBL2
NO
TBP2
Component Code
Failure Mode
TES-Pipe-GB
TES-V3
TES-V4
TES-V5
TES-V6
TES-Valves
TES-Filter-2
TES-IonChamber-3a/b
TES-ColdTrap-4
TES-ColdTrap-4
TES-Recuperator-5
TES-Heater-7
TES-Compressor-8
TES-Water Collector-10
TES-Blower-11a
TES-ReliefT-12
TES-Blower-11b
TES-Diffusor-13
TES-GetterBed-14
TES-HeBufferVessel-15
TES-Blower-11c
TES - He purge gas Piping routing inside the TES glove box: process line in GB
TES - Valve 6 to open a short loop to purge the TBM without operating the extraction line of the TES
TES - Filter
TES - Cold Trap
TES - Cold Trap
TES - Recuperator
TES - Heater
TES - Compressor
TES - Water Collector
TES - Blower
TES - Relief Tank
TES - Blower
TES - Diffuser
TES - Getter Bed (2 Units)
TES - Helium Buffer Vessel
TES - Blower
IPCE-TES-Pipe
IPCE-TES-V1
IPCE-TES-V2
IPCE-TES-CheckV
IPCE -Tritium Extraction System - Purge gas piping (Inlet/Outlet)
Valve external leak
Valve external leak
IPCE -Tritium Extraction System - Check Valve in the inlet tube to the TBM to stop the propagation of a rising pressure Valve external leak
from the TBM side
IPCE -Tritium Extraction System - Pressure reducing Valve installed at the outlet of the TBM to avoid over- Valve external leak
pressurization of TES loop in case of He coolant leaks inside TBM
TES - He purge gas Piping routing in the Vertical Shaft and Building to get the TES glove box in the tritium building
Rupture
IPCE-TES-PrRedValve
Valve external leak
Valve external leak
Valve external leak
Valve external leak
Valve external leak
External leak
External leak
External leak from the gas stream volume
External leak from the water sump
External leak
External leak
External leak
External leak
External leak
External leak
External leak
External leak
External leak
External leak
External leak
External leak
NO
VBG1
TBM - FSW - Welds to assemble the Caps with the FSW - part of the welds sealing the front part of the TBM volume Rupture
hosting BUs
NO
VBG2
TBM - FSW - Welds to assemble the Caps with the FSW - part of the welds sealing the front part of the TBM volume Loss of leak tightness
hosting BUs
Loss of leak tightness of weld located in VV
TBM-PP-IS-HePurgeFT
Appendix C
Page 6 of 9
Op.
PIEs
St.
NO VVA2
Component Code
TBM-PP-IS-AttP-FlexCartr
TBM-PP-IS-HeCoolFT
TBM-PP-IS-HePurgeFT
TBM-PP-IS-DiagnFT
PP-Flange-LipWeld
Appendix C
Failure Mode
TBM - Port Plug - Interface System - Attachment Plate - Flexible Cartridges: to fix TBM box to PP and to cope with Rupture
radial forces and moments in the radial poloidal plane
Loss of bellow leak tightness
TBM - Port Plug - Electrical Feedthroughs for Diagnostics
Port Plug - Flange - Lip Welds
Page 7 of 9
Op.
PIEs
St.
NO N/S
Component Code
TBM-FSW-Be
TBM-Grid-BUWeld
TBM-PurgSepP-Welds
TBM-PurgSepP-Welds
Failure Mode
IPCE-HCS-I&C -P
IPCE-HCS-I&C -T
TBM - First Side Wall - Beryllium protective layer in the FW side
Detachment of Be layer from FSW
TBM - Grid - Welds to assemble the BU to Grid
Rupture
Rupture
TBM - Bottom Plate Manifold 1 - Inlet Collector. Welds of the collector seal different zones of the He coolant inlet to Loss of weld leak tightness
FSW
TBM - Bottom Plate Manifold 1 - Inlet Collector. Welds of the collector seal different zones of the He coolant inlet to Rupture
FSW
TBM - Port Plug - Interface System - Attachment Plate: weld to FW and cap, screw to BPM. Close race track with Plate deformation
tightness weld
Valve fail to open or to remain open
IPCE -Tritium Extraction System - Check Valve in the inlet tube to the TBM to stop the propagation of a rising pressure Valve fail to open or to remain open
from the TBM side
IPCE - part of HCS inside IPC - Valve 3 is a mass control valve to share the flow between the outlet and the bypass lines Valve failure to remain open
from TBM.
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Pressures
Erratic/No output
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Temperatures
Erratic/No output
IPCE-HCS-I&C -Q
HCS-Recuperator
HCS-HX
HCS-HX
HCS-HX
HCS-Heater
HCS-V1
HCS-V2
IPCE - part of HCS inside IPC - Instrumentation and Control - Instrumentation to measure Gas Flow Rates
HCS - Electrical Heater
HCS - Valve 2 to control the secondary circuit of the cooler to have influence on the circulator inlet temperature
HCS-V4
HCS-V4
HCS-V5
HCS-V5
PCS-Compressor
PCS-V3
PCS-V9
PCS-V10
CPS-Heater-2a
Valve fail to close
Valve fail to close
Fail to operate
Fail to operate
CPS - Electrical Heater (2a) to increase the T of the He stream to 450° C, i. e. to the operation temperature of the Fail to operate
catalytic oxidizer
Oxidizer deterioration
Fail to operate
CPS - Blower
Fail to operate on demand
TBM-PP-IS-AttP
IPCE-TES-V1
IPCE-TES-V2
IPCE-TES-CheckV
IPCE-HCS-V3
CPS-Oxidezer-3
CPS-Cooler-4
CPS-Blower-5
Appendix C
Erratic/No output
Internal leak
External leak
External rupture
Single pipe plugging
Fail to operate
Valve fail to open
Valve external leak
Page 8 of 9
Op.
St.
PIEs
(cntd)
Component Code
Failure Mode
CPS-Adsorber-6a/6b
CPS-Adsorber-6a/6b
CPS-Heater-2b
CPS-HeMakeUp
CPS - Electrical Heater (2b) to warm up the gas coming from the adsorbers (No. 6a/b)
Molecular bed deterioration
Spurious activation of heater
Fail to operate
Fail to operate: addition of H2 low with respect to design parameters
CPS-HeMakeUp
Fail to operate: addition of H2O low with respect to design parameters
CPS-Valves
TES - He purge gas Piping routing in the Vertical Shaft and Building to get the TES glove box in the tritium building
Loss of leak tightness in internal tube
TES-V3
TES-V4
TES-V5
TES-V6
TES-Valves
TES-Cooler-1
TES-Cooler-1
TES-Filter-2
TES-IonChamber-3a/b
TES-ColdTrap-4
TES-ColdTrap-4
TES-Recuperator-5
TES - Valve 6 to open a short loop to purge the TBM without operating the extraction line of the TES
TES - Cooler
TES - Cooler
TES - Filter
TES - Cold Trap
TES - Cold Trap
TES - Recuperator
TES-Heater-7
TES-Compressor-8
TES-HeMakeUp-9
TES - Heater
TES - Compressor
Inner pipe leak
Fail to operate
Clogging
Erratic/No output
Fail to operate
Plugging
Internal rupture
Molecular bed deterioration
Fail to operate during operating phase (i.e.: detritiation and cleaning of
gaseous stream)
Fail to operate during downloading and regeneration phases (e.g.:
Heating coil - fail to operate)
Filter clogging
Fail to operate
Fail to operate
Fail to operate: addition of H2 low with respect to design parameters
TES-HeMakeUp-9
TES-Blower-11a
TES-Blower-11b
TES-Diffusor-13
TES-Blower-11c
TES-Valves
TES - Blower
TES - Blower
TES - Diffuser
TES - Blower
Appendix C
Fail to operate: low or no addition of He in case refilling is required to
compensate leaks from the loop
Fail to operate
Fail to operate
Membrane rupture
Fail to operate
Page 9 of 9

(hcpb) test blanket module

Transcription

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