Conversion processes: Internal Gelation and the Sphere

Transcription

Wir schaffen Wissen – heute für morgen
1st ACSEPT International Workshop
Laboratory for
Nuclear Materials
Nuclear Energy
and Safety
Lisbon, 2. April 2010
Manuel A. Pouchon
Conversion processes:
Internal Gelation and the Sphere-pac concept
1st ACSEPT Intenational Workshop, Lisbon
Table of contents
Introduction
Internal Gelation Process –
Introduction, PSI equipment and an example
•
•
•
•
•
Introduction (different techniques)
Internal gelation process
Equipment
An example: MOX (FUJI program)
Other Matrices
further development at PSI
Application of Sol-Gel process for manufacturing microspheres for “Sphere-Pac”,
coated fuel particles and fuel pellets
• Basic concept
• Example for Carbide fuel
• Pellet as end product
• Spherepac
• Example for Spherepac filling (FUJI)
Conclusions / Conclusions
Introduction: Motivation - Task
What is it
Replacement of pellets by a
particle type (Sphere-pac or
Vipac) fuel
Motivation
Particle fuel
(Sphere-pac) concept
for fast reactors (FR)
Task
Starting
nitrate
solution
Why Sphere-pac:
Simple (dustless) process
with good swelling
behavior
Production
of particles
Packing of
particles
Fine, Middle & Coarse Sphere Production
fine-,
middle-
and
coarse-fraction
Example for 3 size fractions
Example
fine
40 µm
15300 drops/s
medium
275 µm
1000 drops/s
coarse
1.2 mm
6 drops/s
Band-filters (I)
Chlorothene
(1,1,1-trichloroethane)
-washing
Cleaning from
silicon oil and from
gelation residuals
Band-filters (II)
Ammonia-washing
Sintering
The Fuji Project – Production
An example:
The FUJI project –
(Np-)MOX as Pellet, Sphere-pac and Vipac in an SFR
Collarboration among JNC, PSI and NRG
M.A. Pouchon et al., Fabrication and
Characterization of MOX Microspheres for the
FUJI Project, (2003) 653-657, Proceedings of the
Global 2003 & Poster, New Orleans, Louisiana
(USA), 16-20 Nov 2003.
Targeted sphere parameters:
composition:
MOX :
80% U - 20% Pu
Np-MOX : 75% U - 20% Pu - 5% Np
(at% in metal, verified by ICP-MS)
size fractions:
coarse
(diameter): 800 µm
for filing process:
parallel/infiltr.
middle
190 µm
fine
70 µm
parallel
infiltration
The Fuji Project – Production
Parameters for the internal gelation
Production parameters for MOX microspheres (FUJI project):
(20% Pu in metal)
metal solution:
nitrate / metal = 1.9 mol·mol-1
metal concentration = 1.4 mol·kg-1
feed solution:
HMTA / metal = 1.3 mol·mol-1
metal concentration = 0.8 mol·kg-1
temperature: 273 K
oil temperature: ~374 K
calcinations:
sintering:
873 K for 3 h, 200 K·h-1, Ar-7% H2
1673 K for 4 h, 300 K·h-1, Ar-7% H2 with humidification
The Fuji Project – Production - Results
O/M RATIO: thermogravimetric measurement
Result:
oxygen to metal ratio
MOX
Np-MOX
coarse middle
fine
coarse
fine
1.9556 1.9552
1.9767
1.947
1.9757
All materials fulfill the specification (1.94<O/M<1.99)
Lattice parameters / Phases: by XRD
Results:
Np
Np
lattice parameter in Å
MOX
coarse
middle
5.4538 5.4455
Np-MOX
fine
coarse
fine
5.4534
5.4501
5.4479
O
O
Pu
Pu
All materials have single phase fluorite structure
U
U
The Fuji Project – Production - Results
by gas immersion:
Density
MOX
coarse
middle
Np-MOX
fine
96.6
100
10.57
10.96
coarse
Relative densities [%]
99.7
Absolute densities [g cm-3]
10.9
fine
100
98.1
10.99
10.8
Ceramography
Picture analysis
Bad Example for MOX
Good-Example for Np-MOX
pore analysis:
varying porosity → result depends on sphere selection
→ different porosity than by immersion
→ no quantitative but qualitative result
FUJI – Results (V): α-autoradiography (I)
No „hotspot“ found
in any sample
(r: radius of averaging procedure)
reference-bar 40% Pu
original
r = 50 μm
r = 100 μm
FUJI – Production - Results : α-autoradiography (II)
FUJI – Production – Results – Ceramography
Example: Grain size by chemical etching
Other products
Uranium-Zirconium-Carbonitride
Inert Matrix 80Zr-10Y-10Ce OXIDE
GEL
(Zr0.83U0.17)(C0.52N0.48),
O-Cont.=0.046%
Sintered
M. Burghartz et. al, Fabrication of inert
matrix fuel for the incineration of plutonium
- a feasibility study, ENC 98 World Nuclear
Congress, Nice (France), 25-28 Oct 1998
Future: PINE – Introduction / Motivation
(U,Pu)C Particle fuel
(Spherepac) concept
for fast reactors (FR)
New internal
gelation process
with µ-Waves
Why (U,Pu)C:
Fast flux compatible, good
thermal conductivity
Why Spherepac:
Simple (dustless) process
with good swelling
behavior
Why µ-Waves:
Simpler process with less
waste
Basic concepts: Sphere-Pac - Pellet
Fuel-Forms: Pellet
Pellet as end-product
Powderroute
1
Wet-route 2
& milling
Wet3
route
Powderpressing
Oxide Æ LWR / SFR
Hybride Æ LWR /
SFR
Fuel-Forms: Pellet - comparison
+ Very established (cheap) process
+ Simple direct powder mixing and pressing
- Initially not a solid solution
- Sophisticated powder mixing required (attrition mill)
- Very powder intensive
1
2
+
+
+
-
Simple if coming from aqueous reprocessing
Initially solid solution
Less powder intensive (no extensive mixing required)
Sophisticated gelation technique
Washing procedures
Liquid waste
3
+ Almost dust-free
+ Less mechanical devices
- Sphere character potentially remains in end-product
Powderroute
1
Wet-route 2
& milling
Powderpressing
Wet3
route
Fuel-Forms: Pellet – Comparison: powder-spheres
Nitride Pellets
G. Ledergerber, Preparation of uranium
nitride in the form of microspheres,
Journal of nuclear materials 188 (1992)
28-35
Particle fuel: Spherepac-Vipac
M. Nakamura et al., Development of Vibro-Packed
Fuel Design Code (振動充てん燃料設計コードの
開発), 資料番号 (Sikuru Kiko Giho) 15-5 (JNC
Technical Review): JNC TN1340 2002-001 (62002) 47-57 ISSN: 1344-4329
Reprocessing
Vipac
Spherepac
Dry
Aqueous
Predicted fuel temperatures
Fuel center temperatures
are expected to decrease
when full power is
reached due to fuel
restructuring/sinter
mechanisms.
Sinter state to be
validated during PIE.
Sintering and thermal
conductivity depend on
as-fabr. smear density.
Sphere-pac Filling for Irradiation Tests of the
FUJI Project
Ch. Hellwig, P. Heimgartner, Y. Tomita, S. Kono, M.A. Pouchon
Paul Scherrer Institut, Switzerland
in collaboration with
Japan Nuclear Cycle Development Institute
Ch. Hellwig et al., Sphere-pac filling for
Irradiation Tests of the FUJI Project, (2003) 19741978, Proceedings of the Global 2003, New
Orleans, Louisiana (USA), 16-20 Nov 2003..
Parallel filling
Infiltration filling
Filling procedures
Infiltration filling
Parallel filling
Prallel- & Infiltration-filling - Parameters
Cladding inner diameter: 6.7 mm
Coarse fraction:
710-800 µm
Fine fraction:
180-212 µm
Weight ratio
coarse to fine fraction: 3.3
Cladding inner diameter: 6.7 mm
Coarse fraction: 710-800 mm
Fine fraction: 63-75 mm
(Dcoarse/Dfine > 8)
Weight ratio coarse to fine fraction: 2.8
PINE – History: AC3-Program - (U,Pu)C in fast flux
G. Bart et al., AC-3-irradiation test of sphere-pac
and pellet (U,Pu)C fuel in the US Fast Flux Test
Facility, J. Nucl. Mat. 376[1] (2008) 47-59
FFTF
Pellet
Particle
cm
mm
Accommodation of
(U,Pu)C Swelling
Summary / Conclusions
• MA-containing fuel (from reprocessing) is difficult to
handle
Æ Simple dustless process is advantageous
Æ Internal gelation together with Sphere-pac fuel is simple
dustless concept
Æ Internal gelation is a well experienced production method
which is able to produce oxides, nitrides and carbide fuels
Æ Sphere-pac fuel is a well experienced concept which was
tested in (many) irradiation programs (+ swelling behavior, thermal conductivity, fission gas release)
Acknowledgements
•We would like to thank the CCEM-CH competence
center for partially financing the PINE project

Conversion processes: Internal Gelation and the Sphere

Transcription

Similar documents