RRFM 2009 Transactions - European Nuclear Society

STATUS AND PERSPECTIVES OF FUEL DEVELOPMENTS FOR
FAST NEUTRON REACTORS OF 4 TH GENERATION
C. RENAULT, J. ROUAULT, P. ANZIEU
CEA/Saclay, DEN/DDIN, 91191 Gif s/ Yvette, France
ABSTRACT
The R&D strategy in France on future reactors gives first priority to developing a
new generation of fast neutron nuclear systems and recycling technologies so as to
assure a sustainable and environment friendly electricity production in the second
half of the 21 st century. SFR is the reference option, not only in France but also in
Europe. The European strategy considers both the GFR and LFR as alternatives to
the SFR.
A common concern is to achieve a convincing demonstration of the capability of
fuels to attain the ambitious goals set to 4 th generation fast neutron systems,
especially in terms of performance (uranium conversion, minimization of long life
radioactive wastes) and safety.
Owing to the important and satisfactory feedback experience built upon oxide fuels,
MOX is the reference fuel for the SFR, at least for the start-up of the prototype
(ASTRID). The objectives followed for the 4 th generation SFR for safety (for
example sodium void worth reduction and limited core reactivity excess) and cycle
performances (self-sustainable core with a near zero breeding gain, reasonable incore
Pu inventory, MA transmutation) are achievable with an oxide fuel in large
power cores (3600 MWt) while implementing adequate design features.
Nevertheless, recent calculations show that the use of a dense and cold ceramic
fuel might even improve the core performances. Carbide and nitride are candidate
fuels to be seriously investigated for SFRs of 4 th generation. For the GFR and the
LFR, dense fuels are required to achieve self-generation because of the higher
fraction of coolant in the core. Carbide and nitride are currently the reference fuels
for the GFR and LFR, respectively.
Focused on some key design parameters (such as high breeding capability, safety,
expected performances of the fuel cycle based on pyro-metallurgical processes),
several countries (India, China, Korea, Japan, USA) are considering the metal fuel
for the SFR either as a long term reference or as a challenger to oxide fuel. In such
a context, the merits and drawbacks of the metal fuel option for large SFR cores
must be re-assessed, and its performances compared with that of oxide and
carbide/nitride fuels.
This paper summarizes the current status of fuel development and perspectives.
Basic features of oxide, metal and other fast reactor fuels (carbide and nitride) are
compared from the viewpoints of fuel cycle (fresh fuel fabrication and spent fuel
treatment), in-pile behaviour, core performances, and safety. The paper also briefly
reviews the potential offered by innovative structural materials developed for high
temperature resistance (SiC, refractory metals) for the GFR, or low swelling
behaviour under irradiation (ODS,…) for the SFR.
The role of experimental reactors is underlined for further assessment of the in-pile
behaviour of fuels with representative materials and realistic conditions (burn-up,
MA content, neutron flux…). An optimal use of existing irradiation reactors (Phenix,
Joyo, Monju, BOR-60, BN-600) is necessary until new reactors, under construction
(JHR, CEFR, PFBR) or planned (ALLEGRO, ASTRID) can be put in operation. The
paper pleads for the implementation of multilateral collaboration at the European
and broader international levels for a continuous capability of innovative fuel
qualification.
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