Minor Actinide Recycling Research Articles

Examination of the use of thorium-based fuel for burning minor actinides in European sodium cooled fast reactor

Abstract To reduce the potential and volume of radiotoxicity of radioactive wastes, minor actinides (MAs) elements recovered from discharged fuel are to be recycled. In this context, the main aim of this work is to examine the possibility of using thorium-based fuel for burning extra MAs in the fourth generation European Sodium cooled Fast Reactor (ESFR). For that MCNPX transport code was used to design a representative fuel assembly of this concept. The reference uranium-based fuel was uniformly replaced by thorium mixed with different fractions of MAs and burned for 2050 effective full power days. The influence of MAs on the evolution of reactivity and fuel transmutation is being investigated to ensure the performance of the fuel. Also, different neutronic and safety parameters such as neutron yield, neutron spectrum, neutron flux, effective delayed neutron fraction, Doppler constant, sodium void reactivity coefficient, were computed and their change with MAs content was investigated. Results indicate that recycling of MAs in ESFR using thorium-based fuel has a positive effect on reactivity and transmutation evolution but on other hand has a negative effect on safety parameters.

Burn-Up Analysis of Plutonium and Minor Actinide Recycling on Gas Cooled Fast Reactor (GCFR) Using SRAC COREBN

Research on the analysis of recycling, plutonium, and minor actinides in the Gas Cooled Fast Reactor (GFCR) using SRAC COREBN has been done. This research uses a fuel mixture of uranium, plutonium, and minor actinides. The analysis was conducted with computational simulation using the COREBN code, an additional code to SRAC. The purpose of this research is to find out the influence of the addition of plutonium and actinide on the composition of nuclear fuel at the end of reactor operation and the limitation of the value of the multiplication factor (keff at the end of the reactor burn up period). Found in this research is the final value, the multiplication factor (keff) of 1.19964, and the conversion ratio value of 0.766813 in the burn-up period of 1515 days as well as the maximum power density value of 125.85 watts/cm³, the relative power density value at the radius y of 1,230263 and radius x equal to 1.19737 the atomic density value experienced a change in the number of nuclides in the types of nuclides U235, U238, Pu239, Pu241, Np237, and Am243 at the end of the burn-up period.

Recycling alternatives for minor actinide and plutonium in a boiling water reactor

Recycling is an alternative for reducing minor actinide and plutonium stockpiles from depleted fuel assemblies. In the current study, it is proposed the use of a MOX fuel assembly called MOXIM-MA. It comprises 4 rods with minor actinides, 14 UO2-gadolinium rods, 8 water rods, and 66 MOX fuel rods. This MOXIM-MA design is used in a 2027 MWth BWR, reducing 0.130 kg HM of minor actinide and 5.042 kg HM of Plutonium per fuel assembly at discharge after discharge 4-operating cycles of 18 months each. The reactor core energy produced does not suffer any penalty by using this fuel assembly. There is no need for additional changes to the original control safety system. The radiotoxicity results show almost one magnitude order increase compared with standard UO2 fuel assemblies for the same BWR reactor core. Still, this increase is the same magnitude experienced when MOX fuel assemblies without minor actinide are used. A twin reactor power plant, 2027 MWth per unit, with 20 and 25 years of operational life, is considered to propose a plutonium and minor actinide recycling strategy. Standard UO2 fuel assemblies, at discharge for this plant, produce 0.135 kg HM of MA and 1.707 kg HM of plutonium. By recycling them, at least 6 depleted fuel assemblies are needed for each MOXIM-MA fuel assembly processed. The suggested strategy starts by considering the cumulative amount of minor actinide and plutonium coming from the depleted fuel assemblies discharged during the plant's operating life at the moment of this analysis. The study shows that the MOXIM-MA fuel assemblies will be used in only one of the reactor units in a once-through scheme. It describes how the auto recycling of plutonium and MA could be done to supply the MOXIM-MA fuel assemblies during the rest of the plant's operation. Results promise to deliver the plant's whole operation life a decrease of 39.50% in plutonium inventories and 12.70% in MA inventories, achieving this goal without penalizing energy production.

Minor actinides transmutation in pressurized water reactors. 1. Multiple recycling of minor actinides on the example of one VVER reactor

This article explores the possibilities and conditions of combustion in a pressurized water reactor of its own accumulated minor actinides (MA). The simplest computational model is used: an infinitely extended medium with the distribution and composition of all materials of the fuel assembly of the reactor core, similar to VVER-1200, with uranium dioxide having an initial 235U enrichment of 4.95%. The burnup model is presented in the form of iterations, each of which simulates a fuel campaign lasting 4 years without refueling. At the start of the cycle, special fuel rods are loaded with minor actinides extracted from the reprocessed SNF of the VVER-1200 reactor. After the end of the fuel campaign, all the MAs are removed from the SNF and used in a new iteration. As a result of calculations, it was found that the MA mass in the cycle after 3–7 iterations (depending on the number of fuel elements allocated for the placement and accumulation of MAs) tends to an equilibrium state (regardless of the MAs added every 4 years). In other words, the fuel rods allocated for loading MAs play the role of a kind of furnace, into which, in each iteration, MAs from the previous iteration accumulated in the given reactor are loaded. After several iterations, the burned MA mass converted into fission products is compared with the incoming one. The inclusion of MAs in this way into the fuel cycle converts at least 86% of MAs into fission products without affecting the power generation of the nuclear power plant. It is important that MAs are temporarily unloaded from the reactor after the next iteration in order to remove fission products and to add a new portion of MAs. After stopping the reactor operation, about 16% of the total amount of MAs generated for the entire history of the reactor’s life is discharged into the storage facility. The initial fuel composition in the fuel rods allocated for loading MAs differs from the others only in the amount of MAs and the mass of 238U. The simplified computational model used in this work (without annual overloads of the reactor) influenced the burnup depth and, naturally, the duration of operation, i.e., the k∞ value becomes less than 1 after 1056 days instead of the actual 1460 days with annual fuel overloads. This affected the average fuel composition and, consequently, the neutron spectrum, and could affect the main result of the work, i.e., the number of burned-out MAs in different iterations. Additional calculations, taking into account the annual overloads of the reactor, showed that the change in the spectral composition had little effect on the amount of MAs at the end of the fuel campaign (within 2%). It turned out that the replacement of 238U with minor actinides in fuel rods, the number of which is less than 10, leads to a loss of reactivity. When the number of fuel rods for loading MAs is more than 10, the reactivity increases, giving hope for burning up MAs accumulated in several reactors.

Trip turbine transient and stability analysis of two different fuel assembly designs aimed for the recycling of minor actinides and plutonium in BWRs

Recycling in thermal reactors is an alternative that could help to reduce minor actinide inventories produced by depleted fuel assemblies of nuclear reactors; the current paper assesses two proposed BWR fuel assemblies to recycle MA. These fuel designs aim to no introduce any perturbation in the electricity production from the Boiling Water Reactor, and they must satisfy the reactor core safety constraints. Such constraints must be considered under steady and transient conditions without the need to make any modification to the nuclear reactor safety systems. Previously, these two fuel designs were assessed under steady state conditions. In this study, the two proposed fuel assembly designs are tested for stability analysis and trip turbine transitory conditions. These fuel assembly designs are based on a 10 × 10 standard fuel assembly, and they have four MA-bearing rods that are replacing four fuel rod assemblies in three of the six axial fuel cells that compose the fuel assembly. The first design is a UO2 fuel assembly; the second one is a MOX fuel assembly where also, 8 fuel pin rods have been replaced by water rods in three of the six axial fuel cells that compose the fuel assembly. These two proposed fuel assemblies have been designed to be equivalent by producing the same amount of energy of the BWR reactor. The stability analysis is performed considering a global reactor oscillation; results show that in the MOX fuel assembly, the control rod pattern must be modified to provide an acceptable shutdown margin and to have adequate stability conditions. Both fuel designs provide acceptable conditions under the trip turbine transient condition and provide two fuel assembly designs that could be used for MA recycling in a BWR without any perturbation in energy production.

Dosimetry and methodology of gamma irradiation for degradation studies on solvent extraction systems

Abstract The recycling of minor actinides from dissolved nuclear fuels by hydrometallurgical separation is one challenging strategy for the management of spent fuel. These future separation processes will likely be based on solvent extraction processes in which an organic solvent system (extractant and diluent) will be contacted with highly radioactive aqueous solutions. To establish a separation between different elements in spent nuclear fuel, many extractants have been studied in the past. A particular example is N,N,N′,N′-tetraoctyl diglycolamide (TODGA), which co-extracts lanthanides and actinides from nitric acid solutions into an organic phase (e.g. TODGA in n-dodecane). The radiolytic stability of these extractants is crucial, since they will absorb high doses of ionizing radiation during their usage. Worldwide, different gamma irradiation facilities are employed to expose extractants to ionizing radiation and gain insight in their radiation stability. The facilities differ in many ways, such as their environment (pool-type or dry), configuration and gamma sources (often 60Co or spent nuclear fuel). In this paper, a dosimetric assessment is made using different dosimeter systems in a pool-type irradiation facility, which has the advantage to be flexible in its arrangement of 60Co sources. It is shown that Red Perspex dosimeters can be used to accurately characterize this high dose rate gamma irradiation field (approx. 13.6 kGy h−1), after comparison with alanine, Fricke and ceric-cerous dosimetry in a lower dose rate gamma irradiation field (approx. 0.5 kGy h−1). A final validation of the whole chain of techniques is obtained by reproduction of the dose constants for TODGA in n-dodecane.

Radiolytic degradation of hydrophilic PyTri ligands for minor actinide recycling

The 2,6-bis[1H-1,2,3-triazol-4-yl]-pyridine (PyTri) chelating unit has already shown promising properties for application to advanced hydrometallurgical processes aimed at recovering minor actinides from highly active raffinate. Radiolytic stability is an undeniable key requirement for chemicals involved in highly radioactive solutions partitioning, since radiolysis can have a huge impact on system safety and performances. In this work, the radiolytic degradation of two hydrophilic PyTri complexing agents was investigated by different analytical techniques. The radiation damage was delivered by a 60Co source. The main radiation-induced ligand degradation by-products were hypothesized. Unprecedented PyTri ligands radiolytic stability was proved, further recommending their implementation in future partitioning processes.

Comparison of BWR fuel assembly options for minor actinide recycling

Nuclear energy production generates Minor Actinide (MA) and Plutonium (Pu) isotopes, being these ones the main reason for the longtime storage of the depleted fuel assemblies. A reduction of these produced isotopes will decrease the volume required for their storage and their total elimination could eventually decrease the storage time. A possible alternative for MA reduction is recycling them into Boiling Water Reactor (BWR) cores. It is proposed that the corresponding BWR fuel assemblies into these cores will contain 4 MA bearing-rods. For this purpose a Uranium Oxide (UO2) fuel assembly or a Mixed Oxide (MOX) fuel assembly can be used. For the MOX fuel assembly two types of fuel assemblies are used, the first one only considers the replacement of 4 MOX rods by 4 MA-bearing rods and the last one considers also increasing the fuel-to moderator ratio by the replacement of 8 MOX fuel rods by water rods. The behavior of the designed fuel assemblies is compared against a reference UO2 standard 10x10 BWR fuel assembly. Results show the MA and Pu reduction achieved by the use of each one of the four proposed assemblies. Advantages and disadvantages of the recycling using each one of the fuel assemblies are discussed.

Radionuclide neutron source trajectories in the closed nuclear fuel cycle

Abstract The highest efficiency in the usage of nuclear energy resources can be implemented in fast breeder reactors of generation IV. It is achieved thanks to the ability of consuming minor actinides (MAs) in energy production. One of the options to use this benefit is full recycling of MAs to close the nuclear fuel cycle. Monte Carlo burn up (MCB), an integrated burn-up calculation code, deals with the complexity of the burn-up process which is applied to the European Lead-cooled Fast Reactor (ELFR). MCB uses continuous energy representation of cross section and spatial effects of full core reactor model; however, it automatically calculates nuclide production in all possible reactions or decay channels. Multi-recycling of MAs can cause an intensified build-up of curium, berkelium and californium. Some of their isotopes are strong neutron emitters from spontaneous fission, which hinders fuel recycling. The implementation of a novel methodology for trajectory period folding allows us to trace the life cycle of crucial MAs from the beginning of the reactor life towards the state of adiabatic equilibrium. The result of the analysis performed is presented, showing the sources of strong contribution to the neutron production rate. The parametric sensitivity analysis method for selected nuclide reactions is applied, revealing sensitivity of transmutation chains for the production of neutron emitter isotopes.

Analysis of minor actinide recycling using MOX fuel assemblies in a Boiling Water Reactor

BWR depleted fuel assemblies contain minor actinide (MA) and plutonium isotopes that must be stored for long periods of time for safety reasons, recycling of MA and plutonium is an alternative that could help to reduce the amount of high-level radioactive waste produced in a nuclear power reactor. Recycling of plutonium in MOX fuel is a proved option and several commercial reactors have MOX fuel as part of their reloads. MA recycling in a Boiling Water Reactor (BWR) has been analyzed previously by the authors showing that is feasible and the higher MA destruction is obtained when the minor actinide is embedded in uranium fuel assemblies instead of MOX fuel assemblies. However, the recycling of MA in UO2 fuel assemblies generates a higher amount of Pu-238 that is a precursor of Pu fissile isotopes increasing the amount of them in the depleted fuels employed for MA recycling. In this study a new BWR MOX fuel assembly design, that is called MOX-MA, is analyzed. The study takes an equilibrium cycle of a BWR as the reference cycle and then it proposes the use of an equivalent MOX fuel assembly in which 4 fuel rods are replaced by MA-bearing rods and 8 fuel rods are also replaced by water rods to increase moderation-to-fuel-ratio. The study aims to have the maximum amount of this new MOX BWR fuel assembly design, called MOX-MA, which can be used by reload in the core. The proposed MOX-MA fuel assembly can be used as a full reload and for a whole MOX-MA core there is no need to modify any of the control systems and this whole MOX-MA core produces the same amount of electricity than the UO2 reference equilibrium core. By using the MOX-MA fuel assemblies there is a plutonium net reduction of 33% and there is practically not production of MA.

Effects of Am and Cm distributions on neutronic parameters of MINERVE reactor

Minor actinide recycling and transmutation are important stages in the advanced nuclear systems design such as Generation IV reactors that offers a high level of safety, waste reduction, and minimizes its environmental and radiological impacts. In the present work, two preliminary model configurations are used to examine the effects of adding two long-lived isotopes of minor actinides (243Am and 247Cm) in MINERVE reactor reference core (R1-UO2) that represents a LWR loaded with UO2 fuel rods. The effects are studied in two models of uniform and nonuniform minor actinides distributions, and include the numerical evaluation of neutronic parameters such as neutron spectrum, flux distribution and fission rate, using MCNPX transport code. The analysis of and comparison between the uniform and nonuniform models have been discussed to evaluate which of either is expected to be favored for minor actinide transmutation and energy production.

In-situ High Temperature X-ray Diffraction Study of the Am-O System

ABSTRACTIn the frame of minor actinide recycling, (U,Am)O2 are promising transmutation targets. To assess the thermodynamic properties of the U-Am-O system, it is essential to have a thorough knowledge of the binary phase diagrams, which is difficult due to the lack of thermodynamic data on the Am-O system. Nevertheless, an Am-O phase diagram modelling has been recently proposed by Gotcu. Here, we show a recent investigation of the Am-O system using in-situ High Temperature X-ray Diffraction under controlled atmosphere. By coupling our experimental results with the thermodynamic calculations based on the Gotcu model, we propose for the first time a relation between the lattice parameter and the departure from stoichiometry.

Impact of minor actinide recycling on sustainable fuel cycle options

The recent Evaluation and Screening study chartered by the U.S. Department of Energy, Office of Nuclear Energy, has identified four fuel cycle options as being the most promising. Among these four options, the two single-stage fuel cycles rely on a fast reactor and are differing in the fact that in one case only uranium and plutonium are recycled while in the other case minor actinides are also recycled. The two other fuel cycles are two-stage and rely on both fast and thermal reactors. They also differ in the fact that in one case only uranium and plutonium are recycled while in the other case minor actinides are also recycled. The current study assesses the impact of recycling minor actinides on the reactor core design, its performance characteristics, and the characteristics of the recycled material and waste material.The recycling of minor actinides is found not to affect the reactor core performance, as long as the same cycle length, core layout and specific power are being used. One notable difference is that the required transuranics (TRU) content is slightly increased when minor actinides are recycled. The mass flows are mostly unchanged given a same specific power and cycle length.Although the material mass flows and reactor performance characteristics are hardly affected by recycling minor actinides, some differences are observed in the waste characteristics between the two fuel cycles considered. The absence of minor actinides in the waste results in a different buildup of decay products, and in somewhat different behaviors depending on the characteristic and time frame considered. Recycling of minor actinides is found to result in a reduction of the waste characteristics ranging from 10% to 90%. These results are consistent with previous studies in this domain and depending on the time frame considered, packaging conditions, repository site, repository strategy, the differences observed in the waste characteristics could be beneficial and help improve the repository performance.On the other hand, recycling minor actinides also results in an increase of the recycled fuel characteristics and therefore of the charged fuel. The radioactivity is slightly increased while the decay heat and radiotoxicities are very significantly increased. Despite these differences, the characteristics of the fuel at time of discharge remain similar whether minor actinides are recycled or not, with the exception of the inhalation radiotoxicity which is significantly larger with minor actinide recycling. After some cooling the characteristics of the discharged fuel become larger when minor actinides are recycled, potentially affecting the reprocessing plant requirements. Recycling minor actinides has a negative impact on the characteristics of the fresh fuel and will make it more challenging to fabricate fuel containing minor actinides.

Radiotoxicity implications and reduction strategies of minor actinide in a boiling water reactor

Radiotoxicity implications for the reactor use of a previously proposed BWR fuel assembly called “MAc”, which contains 4 minor actinide bearing rods, are assessed. Use of this type of fuel assembly in a BWR with a nominal power of 2027MWt shows a reduction of 135.30kg HM of minor actinide per 18-month operating cycle when the whole core is composed of “once-through” MAc fuel assemblies, it is achieved without any penalty in reactor core energy generation and without violating any of the standard reactor safety constraints. The radiotoxicity results show that the use of this type of fuel assembly, that contains minor actinide, does not increase the amount of radiotoxicity that is given when the core is composed by standard UO2 fuel assemblies. A proposed strategy for minor actinide recycling is analyzed where a nuclear power plant that is composed by two 2027MWt reactor units with 25 and 20years of operation, respectively is taken as the base case. Results show that at least 4 BWR depleted fuel assemblies are needed to get enough minor actinide material to provide the 4 minor actinide bearing rods for the MAc fuel assembly. The proposed strategy shows the amount of cumulative depleted fuel at the moment of this analysis and the number of fuel reloads that can be supplied along with the total reduction of minor actinide assuming a once-through use of the MA fuel assemblies. Results of this strategy show a decrease in the amount and volume of depleted fuel because the use of the MAc fuel assemblies, minor actinide recycling strategy achieves the goal of radiotoxicity reduction without any disturbance to the power plant energy production.

Hydrophilic Clicked 2,6-Bis-triazolyl-pyridines Endowed with High Actinide Selectivity and Radiochemical Stability: Toward a Closed Nuclear Fuel Cycle.

There is still an evident need for selective and stable ligands able to separate actinide(III) from lanthanide(III) metal ions in view of the treatment of the accumulated radioactive waste and of the recycling of minor actinides. We have herein demonstrated that hydrophilic 2,6-bis-triazolyl-pyridines are able to strip all actinides in all the different oxidation states from a diglycolamide-containing kerosene solution into an acidic aqueous phase. The ascertained high actinide selectivity, efficiency, extraction kinetics, and chemical/radiolytic stability spotlight this hydrophilic class of ligands as exceptional candidates for advanced separation processes fundamental for closing the nuclear fuel cycle and solving the environmental issues related to the management of existing nuclear waste.

The effectiveness of full actinide recycle as a nuclear waste management strategy when implemented over a limited timeframe – Part I: Uranium fuel cycle

Disposal of spent nuclear fuel is a major political and public-perception problem for nuclear energy. From a radiological standpoint, the long-lived component of spent nuclear fuel primarily consists of transuranic (TRU) isotopes. Full recycling of TRU isotopes can, in theory, lead to a reduction in repository radiotoxicity to reference levels corresponds to the radiotoxicity of the unburned natural U required to fuel a conventional LWR in as little as ∼500 years provided reprocessing and fuel fabrication losses are limited. This strategy forms part of many envisaged ‘sustainable’ nuclear fuel cycles. However, over a limited timeframe, the radiotoxicity of the ‘final’ core can dominate over reprocessing losses, leading to a much lower reduction in radiotoxicity compared to that achievable at equilibrium. The importance of low reprocessing losses and minor actinide (MA) recycling is also dependent on the timeframe during which actinides are recycled. In this paper, the fuel cycle code ORION is used to model the recycle of light water reactor (LWR)-produced TRUs in LWRs and sodium-cooled fast reactors (SFRs) over 1–5 generations of reactors, which is sufficient to infer general conclusions for higher numbers of generations. Here, a generation is defined as a fleet of reactors operating for 60 years, before being retired and potentially replaced. Over up to ∼5 generations of full actinide recycle in SFR burners, the final core inventory tends to dominate over reprocessing losses, beyond which the radiotoxicity rapidly becomes sensitive to reprocessing losses. For a single generation of SFRs, there is little or no advantage to recycling MAs. However, for multiple generations, the reduction in repository radiotoxicity is severely limited without MA recycling, and repository radiotoxicity converges on equilibrium after around 3 generations of SFRs. With full actinide recycling, at least 6 generations of SFRs are required in a gradual phase-out of nuclear power to achieve transmutation performance approaching the theoretical equilibrium performance – which appears challenging from an economic and energy security standpoint. TRU recycle in pressurized water reactors (PWRs) with zero net actinide production provides similar performance to low-enriched-uranium (LEU)-fueled LWRs in equilibrium with a fleet of burner SFRs. However, it is not possible to reduce the TRU inventory over multiple generations of PWRs. TRU recycle in break-even SFRs is much less effective from a point of view of reducing spent nuclear fuel radiotoxicity.

Gamma-radiolytic stability of new methylated TODGA derivatives for minor actinide recycling.

The stability against gamma radiation of MeTODGA (methyl tetraoctyldiglycolamide) and Me2TODGA (dimethyl tetraoctyldiglycolamide), derivatives from the well-known extractant TODGA (N,N,N',N'-tetraoctyldiglycolamide), were studied and compared. Solutions of MeTODGA and Me2TODGA in alkane diluents were subjected to (60)Co γ-irradiation in the presence and absence of nitric acid and analyzed using LC-MS to determine their rates of radiolytic concentration decrease, as well as to identify radiolysis products. The results of product identification from three different laboratories are compared and found to be in good agreement. The diglycolamide (DGA) concentrations decreased exponentially with increasing absorbed dose. The MeTODGA degradation rate constants (dose constants) were uninfluenced by the presence of nitric acid, but the acid increased the rate of degradation for Me2TODGA. The degradation products formed by irradiation are also initially produced in greater amounts in acid-contacted solution, but products may also be degraded by continued radiolysis. The identified radiolysis products suggest that the weakest bonds are those in the diglycolamide center of these molecules.

Americium-based oxides: Dense pellet fabrication from co-converted oxalates

Mixed oxides are used as nuclear fuels and are notably envisaged for future fuel cycles including plutonium and minor actinide recycling. In this context, processes are being developed for the fabrication of uranium–americium mixed-oxide compounds for transmutation. The purpose of these processes is not only the compliance with fuel specifications in terms of density and homogeneity, but also the simplification of the process for its industrialization as well as lowering dust generation. In this paper, the use of a U0.85Am0.15O2±δ powder synthesized by oxalate co-conversion as a precursor for dense fuel fabrications is assessed. This study notably focuses on sintering, which yielded pellets up to 96% of the theoretical density, taking advantage of the high reactivity and homogeneity of the powder. As-obtained pellets were further characterized to be compared to those obtained via processes based on the UMACS (Uranium Minor Actinide Conventional Sintering) process. This comparison highlights several advantages of co-converted powder as a precursor for simplified processes that generate little dust.

Assessment of proliferation resistances of aqueous reprocessing techniques using the TOPS methodology

The aim of this study is to assess and compare the proliferation resistances (PR) of three possible Generation IV lead-cooled fast reactor fuel cycles, involving the reprocessing techniques Purex, Ganex and a combination of Purex, Diamex and Sanex, respectively. The examined fuel cycle stages are reactor operation, reprocessing and fuel fabrication. The TOPS methodology has been chosen for the PR assessment, and the only threat studied is the case where a technically advanced state diverts nuclear material covertly.According to the TOPS methodology, the facilities have been divided into segments, here roughly representing the different forms of nuclear material occurring in each examined fuel cycle stage. For each segment, various proliferation barriers have been assessed. The results make it possible to pinpoint where the facilities can be improved.The results show that the proliferation resistance of a fuel cycle involving recycling of minor actinides is higher than for the traditional Purex reprocessing cycle. Furthermore, for the purpose of nuclear safeguards, group actinide extraction should be preferred over reprocessing options where pure plutonium streams occur. This is due to the fact that a solution containing minor actinides is less attractive to a proliferator than a pure Pu solution. Thus, the safeguards analysis speaks in favor of Ganex as opposed to the Purex process.

Recycling the Actinides, The Cornerstone of Any Sustainable Nuclear Fuel Cycles

The sustainability of the current nuclear fuel cycles is not completely achieved since they do not optimise the consumption of natural resource (only a very small part of uranium is burnt) and they do not ensure a complete and efficient recycling of the potential energetic material like the actinides. Promoting nuclear energy as a future energy source requires proposing new nuclear systems that could meet the criteria of sustainability in terms of durability, bearability and liveability. In particular, it requires shifting towards more efficient fuel cycles, in which natural resources are saved, nuclear waste are minimised, efficiently confined and safely disposed of, in which safety and proliferation-resistance are more than ever ensured. Such evolution will require (i) as a mandatory step, evolutionary recycling of the major actinides U and Pu up to their optimized use as energetic materials using fast neutron spectra, (ii) as an optional step, the implementation of the recycling of minor actinides which are the main contributors to the long term heat power and radiotoxicity of nuclear waste. Both options will require fast neutrons reactors to ensure an efficient consumption of actinides. In such a context, the back-end of the fuel cycle will be significantly modified: implementation of advanced treatment/recycling processes, minor-actinides recovery and transmutation, production of lighter final waste requiring lower repository space. In view of the 2012 French milestones in the framework of the 2006 Waste Management Act, this paper will depict the current state of development with regards with these perspectives and will enlighten the consequences for the subsequent nuclear waste management.