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International audience; In accordance with the French Act of 28 June 2006 on the sustainable management of radioactive materials andwaste, this paper summarises the technical characterisation of prospective scenarios using different fuel cycleoptions: open cycle, recycling of plutonium and uranium in PWRs (current option for the French nuclear powerfleet), multiple recycling of plutonium in SFRs, and multiple recycling of plutonium in PWRs. This informationhas been submitted by the CEA to the Ministry of Energy within the scope of Article 51 of the Ministerial Orderdated 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 (theassumption of some past studies), it was decided to study a scenario involving a more progressive deployment onthe basis of existing materials and facilities. This solution appears to be better suited to the dynamics oftechnical progress in the field, while providing greater flexibility to adapt to societal changes. The path for thisscenario is marked by successive milestones (stages), with each corresponding to an increased deployment offast reactors with their own increasingly ambitious objectives.Phase A corresponds to the current state of the French nuclear reactor fleet wherein plutonium and uranium arerecycled 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 ofthis phase is to stabilise the quantities of spent MOX fuels from light water reactors. Phase C is designed to beable to stabilise the plutonium inventory by deploying a symbiotic fleet comprising UOX-PWRs, MOX-PWRs andSFRs. The objective of phase D is to deploy a fleet of reactors that no longer burns natural uranium. There aretwo possible options for a nuclear fleet that can generally be considered as self-sufficient, i.e. D1, ahomogeneous fleet with 100% SFRs, and D2, a mixed fleet comprising breeder SFRs producing plutonium andPWRs fuelled with 100% MOX to burn this plutonium.However, SFRs may not become economically competitive in the next few decades if uranium resources remainreadily available, and MOX spent fuels may start to pile up at the back-end of the fuel cycle unless alternativeplutonium management solutions in PWRs are found. In this study, advanced fuel batches, called CORAIL andMIX, are applied to enable multiple recycling in standard PWRs.The CORAIL concept involves placing both MOX fuel rods with depleted uranium support structures and UOXfuel rods in the same fuel assembly. A configuration based on 84 MOX fuel rods and 181 UOX fuel rods wasstudied in the early 2000s, which is why it has been chosen for the first scenario in this paper. As the enrichmentof UOX rods is maximised at 5%, the plutonium content is adapted to make up for its loss of fissile quality witheach recycling phase.The MIX concept is based on a fuel assembly containing only MOX fuel rods with enriched uranium supportstructures. The purpose in this case is to limit the plutonium content in the fuel to a level similar to that ofcurrent MOX fuels and to meet any additional needs in fissile nuclei by providing enriched uranium in thesupport. The greater the isotopic degradation of plutonium, the greater the enrichment will be, which will beincreased with each recycling phase to make sure $^{235}$U is stabilised at around 3% to 4%. Three plutoniumcontents 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 theAndra disposal concept. The assessment of the resulting waste volumes depending on the option is given inanother paper, also presented at this conference.

International audience; This paper presents the industrial feasibility analysis of scenarios involving the progressive deployment of multiple recycling of plutonium in French sodium fast reactors (SFR), in line with the French Act dated 28 June 2006 on the sustainable management of radioactive materials and waste. Four successive phases have been defined with different degrees of SFR deployment in order to understand how best to accomplish this fuel cycle transition.

International audience; Nuclear systems, composed of reactors and fuel cycle facilities, are complex and in constant evolution. Fuel cycle scenario studies aim at evaluating the consequences of decisions taken in the near term on the eventual outcomes of a chosen fuel cycle.Scenario studies require a large amount of data and hypotheses, such as the energy demand and its evolution or the performances and characteristics of existing and future technologies. Each hypothesis, represented by a parameter, is a potential source of uncertainty that can impact the scenario outcomes. The Nuclear Energy Agency's Expert Group on Advanced Fuel Cycle Scenarios (NEA/AFCS) recently completed an activity that used sensitivity studies to evaluate the impact of uncertainty of the primary scenario input parameters on scenario results.At the beginning of the study, a base case scenario was specified and evaluated. It considers a PWR UOX reactor fleet using low enriched uranium oxide fuel and its gradual replacement by a sodium fast reactor (SFR) fleet using uranium/plutonium mixed oxide fuel. Each member of the group evaluated this scenario with its own scenario code (COSI, COSAC, FAMILY, SITON, TR_EVOL or VISION). It is noteworthy that the different codes show a good consistency in the results and that the differences have been investigated and documented in order to ensure a strong basis for comparison in the sensitivity study.Then, 17 key input parameters and their range of variation as well as 22 scenario outputs were identified and sensitivity analyses were conducted. The key parameters were chosen amongst the general assumptions on the scenario (energy demand, introduction date of fast reactor), reactors and facilities characteristics (burn-ups, losses at reprocessing) and some minor actinides recycling parameters. As far as possible, each parameter was varied independently from the others. This sensitivity study shows the relative impact of each parameter on each output metric. In order to compare the large amount of results, two methods of summarization were adopted, as described in the paper. These comparisons have shown that some parameters, such as the energetic production or the introduction date of fast reactors, have a strong impact on the results whereas others, like the UOX fabrication time, have almost no impact on the studied scenario.

International audience; After the studies carried out in the frame of the 2006 French act for waste management, the CEA, EDF and AREVA decided to work together on potential progressive transition scenarios from the current French nuclear fleet to a SFR fleet which does not require natural uranium to operate. This paper describes one of these scenarios.The first part of the paper focuses on the presentation and results of this transition scenario, with no minor actinides (MA) transmutation taken into account. The scenario starts with the current French fleet and its replacement by an EPR reactor fleet in which plutonium keeps on being monorecycled. MOX PWR spent fuel (SF) reprocessing begins in 2040 in order to feed three breakeven SFR, commissioned between 2050 and 2059. To prepare for a larger SFR deployment, three more SFRs are commissioned between 2075 and 2085 and small-scale SFR SF reprocessing starts in 2060. In 2090, additional SFR are deployed in order to stabilize total plutonium and used fuels inventories, with a fleet composed of 16 breeder SFR and 22 EPR reactors. Finally, between 2150 and 2185, this EPR/SFR reactor fleet is progressively renewed by a new one composed of 41 breakeven SFR. At the end of the scenario, the total Pu inventory is stabilized at 1260t (mostly present in SF and reactor cores) but the MA inventory in the waste is still increasing at a rate of 2.5tHM/y.The following parts of the paper focus on the impact of americium (Am) transmutation in Am bearing blankets (AmBB) loaded in the SFR commissioned in the scenario. Two cases are described, one considering the Am transmutation in the fleet ultimately composed only of SFR, and the other one considering the Am transmutation starting with the mixed SFR/EPR fleet. Finally, one row of AmBB containing 10wt% of Am is enough to stabilize the Am inventory (in both cycle and waste) if the fleet is only composed only of SFR. In the case of a mixed fleet composed of 16 SFRs and 22 moxed EPRs, two rows of AmBB containing 15wt% of Am are required in each SFR core in order to recycle all of the separated Am. However, in that case the total Am inventory is not stabilized as it is still increasing in the spent fuel and blankets. It is noteworthy that, compared to a scenario with Pu multirecycling but without transmutation, Am transmutation in AmBB can lead to a 30% reduction of the radiotoxicity of the waste accumulated all over the scenario.

International audience; After the studies carried out in the frame of the 2006 French Act for waste management, the CEA, EDF and AREVA decided to work together on progressive potential scenarios of the French transition between the current nuclear fleet and a SFR fleet which does not require natural uranium to operate. To do so, several steps were defined, each of them having a different purpose and allowing a gain of experience to move on to the next one.In one of these scenarios, between 2030 and 2062 the current PWR fleet is renewed by an EPR reactor fleet in which plutonium keeps on being monorecycled. This EPR reactor fleet is loaded with about 10% of MOX fuel which enables to stabilize the UOX spent fuel inventory. Beginning from the 2040 decade, a few FR reactors and their associated cycle are progressively introduced MOX PWR spent fuels reprocessing begins in 2040 in order to feed three 1000 MWe breakeven SFR, commissioned between 2050 and 2059.This enables to test at an industrial scale the new Nuclear System and to stabilize used MOX fuel inventory. To prepare for a larger FR deployment, three 1450 MWe breakeven SFR are commissioned between 2075 and 2085. An SFR spent fuel reprocessing of 15 to 21 tHM/y starts in 2060 in order to feed the three 1450 MWe SFR. From 2090, thirteen additional 1450 MWe SFR are deployed in order to reach an equilibrium fleet composed of sixteen 1450 MWe breeder SFR and 22 EPR reactors (with an average MOX load of 39.5%). At this point of the scenario, the Pu global inventory is stabilized, and the energy production remains constant at 420TWhe. From 2150, this EPR/SFR reactor fleet is progressively renewed by a new one composed of 41 breakeven SFR, which does not require natural uranium to operate.SFR deployment in 2150 leads to a slight increase in the global plutonium inventory which stabilizes definitively in 2180. At the end of the scenario, the Pu inventory is reduced by 47% compared with a 100% UOX PWR fleet (open cycle scenario). The global minor actinides inventory is increasing at a rate that can be managed at the back end. Over the whole scenario, 1.01.106 tons of natural uranium have been used. This represents a 40% reduction compared with the open cycle scenario.A faster SFR deployment scenario was also studied, identical to the previous one up to 2090. From 2090, a 41 SFR fleet is deployed according to Pu availability. The equilibrium is reached in 2135 when the global Pu inventory is stabilized.Nuclear phase-outs have been studied at several dates in order to evaluate the impacts in terms of inventories at each step of the scenario. Studies of optimized phase-out, aiming at reducing the Pu global inventory, the spent fuel mass and the waste inventories, have also been carried out. They involve MOX EPR reactors with high moderation ratio and enriched uranium support and burner SFR.

International audience