OECD/NEA, IEMPT-9, september 26-29, 2006 Nîmes, France

Progress in fuels for fast reactors

Ph. MARTIN, M. TOURASSE, N. CHAUVIN , Ph. BROSSARD, D. WARIN
Presented by : Martine TOURASSE

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Nuclear strategy for future reactors
President Chirac decision beginning of 2006
andFrench waste law, june 28th 2006 :GENIIV prototype reactor in service in 2020

1. Sodium fast reactor is the favorite
candidate : background with innovation
2. Gas fast reactor is an alternative :experimental reactor ETDR to be decided
in 2012
3. Both open to international partnership
4. Wide R&D programs to adress key points
5. Technological choices in 2012
6. Industrial development around 2040

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Goals of future system reactors
CLOSED CYCLE• Flexible and efficient use of natural ressources• Significant reduction of long life radioactive
elements in ultimate waste• Proliferation resistant technologies and processes
REACTOR OPTIMISATION• Enhanced economic competitiveness• Still enhanced safety and reliability
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Standard oxide SFR fuel element has been largely experienced
Fuel : (U,Pu)O2

Cross-section ofPhénix Subassembly– Advantages• High melting point > 2 700 °C for 20% Pu• Excellent stability under irradiation– Disadvantages• Poor thermal conductivity : 2.9 W.m-1.K-1• Chemical reactivity with sodium

123.7 mmCladding : swelling is a limitation for high burn up
of SFR fuels– Austenitic Steels seem limited to 130 dpa– Oxide Dispersion ferritic Steels (EM10) could
combine the swelling resistance of ferritic steels
Phénix Subassembly
and thus allow to reach more than 160 dpa

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

… and well simulated by calculation•Example : SANTENAY 1(BU = 9 at% ; LHR ≈ 550 W/cm)

Columnar grain size

Central hole diameter
Radial Pu redistribution

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEMA SFR oxide fuel : SUPERFACT 1 experiment•Demonstration of the MA (Am and Np) transmutation
feasibility (Collaboration between ITU and CEA)•

1986 to 1988 : Irradiation in Phénix Reactor•Fuels¾ 2 Am Pins : Solid solution (U0,74,Pu0,24,Am0,02)O2¾ 2 Np Pins : Solid solution (U0,74,Pu0,24,Np0,02)O2•

Linear power¾ BOL : 380 W/cm (std : 430 W/cm)¾ EOL : 325 W/cm (std : 370 W/cm)

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

SUPERFACT 1 : ResultsÖ Transmutation ratio at the reactor middle plane are ≈ 30 % for237Np and ≈ 28 % for 241Am•Same fuel microstructure evolution thanstandard fuels ones

•U, Pu, Am and Np radial distributions arevery flat Æ No actinides redistribution

Ö For low Linear Power, no real influenceof the low MA amount up to a BU equal
to 6,7 at%, except for the He release ofthe Am fuel (4 times greater thanstandard pins ones)

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Main issue of SFR oxide fuel optimisation
MA fuel manufacturing Process• Powder Metallurgy Process will be very difficult (andexpensive) for MA Fuels– Contamination by fine powders– High number of steps for pellets and pins manufacturing• New process :• limited powder handling and no separation of MA
9 Coprecipitation of powders + Powder Metallurgy
9 Low Pressure Injection of a plastic paste containing
coprecipitated powders• or avoid powder handling and simplify pin fabrication
9 Sol-gel process and spherepac processÖ Two innovative manufacturing processes must beinvestigatedOECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Alternative for SFR fuel
70.35

60.3

50.25

40.2

30.15

20.1

10.05

0vidange FV ($)
gain de regeneration moyen

0(U,Pu)O2

Dependance on the fuel material
is weak for safety parameters,
but significant on the breeding ratio

rapport Vidange/Doppler FV

GRI

Vidange / Doppler

High density fuels (carbides,nitrides) will be assessed as they
may help designing cores withenhanced intrinsic neutronics
characteristics(void worth, doppler coefficient)(U,Pu)C(U,Pu)N

Type de combustible(U,Pu)C looks a good compromise for lower
void/Doppler ratio and higher breeding ratio

Vidange, Doppler ($), Vid / Dop

765vidange FV ($)4(-) doppler FV ($) (Drho)
3rapport Vidange/Doppler FV

210(U,Pu)O2(U,Pu)C(U,Pu)N

Type de combustible

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

International collaborations for irradiation
tests of SFR Fuels•

FrancePhénix shut down is planned in 2009
Canada•

BOR60 could be stopped in 2010

U.S.A.
BrésilÖJOYO could be the last experimental SFR

RoyaumeUni

U.E.
Membresdu ForumInternational Suisse
Génération
IVJaponArgentine
Afrique du Sud Corée du SudÖA collaboration framework between DOE, CEA and JAEA iscurrently in discussion in order to define a common program,particularly on SFR fuels

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEMA SFR fuels : conclusions
•••

•

•

Large experience accumulated on standard SFR oxide fuelSFR oxide fuel behaviour is modelled with a good accuracy even for highburn up and high linear power
Good results on Superfact experiment has been obtained on MA oxideFuels
MAIN GOALS for MA SFR fuel :• manufacturing process for MA fuels• behaviour under irradiation• optimisation of ODS up to 160 dpa• enhanced burnup• Still enhanced safety• modelling
In addition assess dense fuels (carbide, nitride) as alternativecandidates• Optimisation of MA incorporation• Enhanced safety

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEThe fuel element is identified as oneof the major feasibility issue of the GFR•high heavy atom density (typically fuel/structure/gas : 50/10/40 vol%),– high volumic ratio fissile phase / inert materials in the fuel element (between50 / 50 and 70 / 30)– dense fissile phase like carbide or nitride,•fissile phase composition: 18-20% Pu + 78-80% U + 2% M.A. (MinorActinides: Am, Np, Cm),

•Fuel temperature of about 1000-1200°C in normal condition, ~1600°C incase of a depressurization with fission products confinement

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Main fuel requirements for GFR design• High helium temperatures (outlet 850°C)• Low thermal properties of heliumi induces hightemperature for cladding• but « cold » fuel element is needed– Extended life time (gaseous FP release)– Safety in case of depressurization : the low is the temperature , thesafe is the reactor• And FP confinement• Plates design with ceramic cladding anddispersed fuel is the reference for GFR fuels• Pin design is the alternative
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEGFR fuel designs
GFRs
AdvancedCoatedparticles

High density
Dispersion fuels

Cladpellets

HTRs

02550

75

100%vol. of actinide compounds in fuel element
High power density
Microconfinement
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Plate : thermal behaviour at BOL : important thermal gradient in the thickness of the cladcoolant
VAL − ISO (K)Τout. wall = 1144.6 K> 1.14E+03< 1.51E+03
1.15E+03

Δtclad = 158 K

1.16E+03
1.18E+03

Δtgap = 58 K

1.20E+03
1.22E+03
1.23E+03
1.25E+03
1.27E+03

Δtfuel = 146 K

1.28E+03
1.30E+03
1.32E+03
1.33E+03
1.35E+03
1.37E+03
1.39E+03

Tmaxfuel = 1507 K (1234°C)

1.40E+03
1.42E+03
1.44E+03
1.45E+03

Δtgap = 260.5 K
ISOTEMPERATURES MAILLAGE TOTAL en ddV

1.47E+03

Τmax = 1224 K

1.49E+03
1.50E+03

R/D key point : improve thermal conductivity of the clad
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEMechanical behaviour at BOL induced by thermal behaviour

Max. bending (tensile) = 250 MPa

VAL − ISO TRESCA (Pa)> 9.75E+06< 3.13E+08

P13

Coupe en angle

1.21E+07
2.64E+07
4.06E+07
5.48E+07

P7

6.90E+07
8.33E+07

ZGAINE

9.75E+07

Y

1.12E+08

Coupe en milieude plat

1.26E+08

X

1.40E+08
1.54E+08

Point of stress concentration

P12

1.69E+08
1.83E+08(compressive) = 313 MPa

1.97E+08

P11

2.11E+08
2.26E+08
2.40E+08

VOILE DEMATRICE

2.54E+08
2.68E+08

P4P10

2.83E+08

Welding plane

ISOCONTRAINTES DE TRESCA EN DDV DANS GAINE+MATRICE

2.97E+08
3.11E+08

R/D key point : understanding of mechanical properties of the clad
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Plates with pellets : first design
Axial gap : closed at BOL to havehomogeneous thermal behaviour
composite
SiC-SiCfibers

Radial gap: closed at EOL to trap
gaseous fission products

Fission gas

Actinidecompound :UPuC or UPuN
(56%vol of fuel)diffusion barrier
refractory metal : We, Mo, Cr,…

CEA Patent

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Plate design : predicted behaviour under irradiation– Thermomechanical: « designed for »• Low temperature with axial gap closing at BOL (heat transfer) and radial
gap closing at EOL (swelling, FGR)Æ Nominal : Max Temp. 1350°C, depressurization : T~1650°C• Low level primary stresses, gap sized for 70 bars of int. pressure at EOL.
• A reasonable level of secondary stresses: compressive stress (~30 MPa),
1 point under tensile stress (175MPa)– Thermochemical : suspected eutectic (1600-2000°C)
between IM/FC : barrier needed– Tightness:• FP and helium tightness– Effect of minor actinides :• Free volume for He (IM vol. reduced)
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEGFR pin : thermal behaviour and gap closing
Pellet : UPuAmC, UPuAmN Φ = 5,92 mm
Clad: SiC-SiCfibers Φext /Φint = 8.15 /6.15 mmecladding = 1 mm

Fuel temperature(max °C)
T coeur

Radial Gap
Jeu pellet/cladding
radial1600
120z/z0 = 0.2
100

1400

PFM

1200z/z0 = 0.8

1000
°C

µm

80

60

800
600

40z/z0 = 0.2
PFM

400z/z0 = 0.8

20

200
00500

1000

1500

2000

jours

2500

00500

1000

1500

2000

2500

jours

gap closing : too fast
Pellet Cladding MechanicalInteraction

1/ High temp. Æ FG release and swelling activated
2/ gap pollution Æ temp. Ò3/ Then pellet swelling Æ gap closing
4/ temp. Stabilised after pellet/cladding interaction

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Pin concept : predicted behaviour under irradiation– Thermomechanical:• Temp. Max of FC : 1400°C with a possible decrease of 100-200°C
with closed porosity (FGR<10%), internal pressure and gap size
optimisation

Æ increase gap conductance• Cladding stress < 50MPa before pellet/cladding mechanicalinteraction, after >200MPa in tensile stressÆ Burn up limited (8-9at%)– Thermochemical : suspected eutectic (1600-2000°C) betweenIM/FC : liner needed– Tightness: liner needed– Effect of MA :• Free volume for released He outside the core (pin plenum)Æ no effecton power density but effect on core size

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

R&D on ceramic materials (SiC-SiCfiber …)•

SiC-SiCfiber … : Fiber, interphase, matrix optimisation–––•••

Liner, coatings
Interaction between materials (Helium, materials, FPs …)
Damage under irradiation––––•

Thermal properties,Toughtness
Tightness, Thermal creep, Swelling
Strain capacity,

Osiris and Phenix are testing many materials
Experiments with proton or ion
Implanted materials…

Modelling

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Main neutron irradiations on GFR R&D
FUTURIX MI : inert material intended to GFR in Phenix (EOL 2009)CARBIDES – NITRIDES – REFRACTORY METALS••••

Representative of operating conditions
High temperature : 900 – 1000°C
Fast neutron fluence : closed to 1027 n m-2
Dose max. 42 dpa SiC

FUTURIX CONCEPT : UPuN, UPuC/TiN,SiC in Phenix (EOL 2009)••••

Power density: 40 à 100 MW/m3 of core
Max. temperature : 700 - 1200 °C
Burn-up : 5 to 10 at. %Dose max. 42 dpa SiC

GFR-REA in OSIRIS reactor : Material irradiations (EOL 2006 and 2008)••••

Neutron damages on liners materials(W, W-Re, Mo, Mo-Re, V, Cr, Nb, Ti) and ceramic weldings(BRASIC, SPS, …)Composite ceramics under irradiation testing (creep test such as BSR),
Welding of composites or liners testing
Around 500°C up to 2 dpa

IRRDEMO : Demonstration on pre-selected materials and designs (EOL 2012)
OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSEFUTURIX/Concepts

Experimental pellets

UPuN / TiN

UPuC / SiCwelding
He gap

ZrO2

Porous
SiC
dense
SiC
SiC matrix

fissilewelding

He gapOECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, FranceMatrix

M. TOURASSE

Objective : to study irradiation creep of fibers

MECASIC device
under ion beam
(JANNUS project)
Traction , Creep, Dilatation
Electrical conductivity
from : 20 to 1600°C

CEDRIC device
under neutron irradiation(Osiris)
On line elongation measurements
600°C to 1000°C
Strained situation : 200MPa

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

International collaborations for GFR Fuels
GENIV: PMB GFR fuelUSA, Japan, France

GFR fuel

INERI-GFR fuel

CEA-DOEGFR fuel : design,(INL, ANL, ORNL, LANL)

irradiation FUTURIX-MI in Phénix

DOE

fabrication,
behaviour
ATR irradiation
inert materials
high temp.
& fast fluence

Europe : GCFR-STREP WP2ITU, HFR, NRG, CEA

GFR fuel:design, fabrication,
behaviourKyoto university

Pr Koyama

R&D composite:
SiC-SiCf

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE

Orientations for fuel element in future reactor systems•SFR fuel element design
Reference: pin type fuel– with MA in UPuO2 and ODS cladding– Main issue on MA fuel manufacturing and ODS optimisation– Assessment of dense fuels– Still enhanced safety•GFR fuel element design
Reference: plate type fuel, option: pin type fuel– MA in UPC / UPuN with inert matrix-cladding– Main issue on MA fuel manufacturing ceramic material capability, FPbarrier ….

•Both fuel element development with an irradiation program.
– First step : material and design selection (Phénix, Osiris, Joyo …)– Second step : technological choices (2012)– SFR prototype : 2020
– GFR experimental reactor (ETDR) and GFR prototype to be decided
in 2012– Industrial reactors : around 2040

OECD/NEA, IEMPT-9, September 26-29, 2006, Nîmes, France

M. TOURASSE