Prospective inventory of radioactive materials and waste produced by the French nuclear fleet according to various options
Résumé
In accordance with the French Act of 28 June 2006 on the sustainable management of radioactive materials and
waste, this paper summarises the technical characterisation of prospective scenarios using different fuel cycle
options: open cycle, recycling of plutonium and uranium in PWRs (current option for the French nuclear power
fleet), multiple recycling of plutonium in SFRs, and multiple recycling of plutonium in PWRs. This information
has been submitted by the CEA to the Ministry of Energy within the scope of Article 51 of the Ministerial Order
dated 23 February on the French National Radioactive Materials and Waste Management Plan (PNGMDR).
Rather than imagining the large-scale replacement of PWRs by fast reactors within a short period of time (the
assumption of some past studies), it was decided to study a scenario involving a more progressive deployment on
the basis of existing materials and facilities. This solution appears to be better suited to the dynamics of
technical progress in the field, while providing greater flexibility to adapt to societal changes. The path for this
scenario is marked by successive milestones (stages), with each corresponding to an increased deployment of
fast reactors with their own increasingly ambitious objectives.
Phase A corresponds to the current state of the French nuclear reactor fleet wherein plutonium and uranium are
recycled in mixed-oxide (MOX) and enriched reprocessed uranium (ERU) fuels in pressurised water reactors
(PWR). Phase B consists in recycling spent MOX fuel from PWRs in a limited number of SFRs. The objective of
this phase is to stabilise the quantities of spent MOX fuels from light water reactors. Phase C is designed to be
able to stabilise the plutonium inventory by deploying a symbiotic fleet comprising UOX-PWRs, MOX-PWRs and
SFRs. The objective of phase D is to deploy a fleet of reactors that no longer burns natural uranium. There are
two possible options for a nuclear fleet that can generally be considered as self-sufficient, i.e. D1, a
homogeneous fleet with 100% SFRs, and D2, a mixed fleet comprising breeder SFRs producing plutonium and
PWRs fuelled with 100% MOX to burn this plutonium.
However, SFRs may not become economically competitive in the next few decades if uranium resources remain
readily available, and MOX spent fuels may start to pile up at the back-end of the fuel cycle unless alternative
plutonium management solutions in PWRs are found. In this study, advanced fuel batches, called CORAIL and
MIX, are applied to enable multiple recycling in standard PWRs.
The CORAIL concept involves placing both MOX fuel rods with depleted uranium support structures and UOX
fuel rods in the same fuel assembly. A configuration based on 84 MOX fuel rods and 181 UOX fuel rods was
studied in the early 2000s, which is why it has been chosen for the first scenario in this paper. As the enrichment
of UOX rods is maximised at 5%, the plutonium content is adapted to make up for its loss of fissile quality with
each recycling phase.
The MIX concept is based on a fuel assembly containing only MOX fuel rods with enriched uranium support
structures. The purpose in this case is to limit the plutonium content in the fuel to a level similar to that of
current MOX fuels and to meet any additional needs in fissile nuclei by providing enriched uranium in the
support. The greater the isotopic degradation of plutonium, the greater the enrichment will be, which will be
increased with each recycling phase to make sure $^{235}$U is stabilised at around 3% to 4%. Three plutonium
contents have been considered in our study: 8%, 9.54% and 12%.
This paper assesses the material flows and inventories for these various options on the basis of two approaches:
1) static (or in equilibrium) by supposing that each option is artificially maintained long enough, and 2) dynamic
(for transition scenarios).
The total disposal surface area required for each of the different options is also discussed on the basis of the
Andra disposal concept. The assessment of the resulting waste volumes depending on the option is given in
another paper, also presented at this conference.
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