Futuristic back-end of the nuclear fuel cycle with the partitioning of minor actinides (original) (raw)
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Procedia Chemistry, 2012
In the framework of the successive 1991 and 2006 Waste Management Act, French government supported a very significant R&D program on partitioning and transmutation of minor actinides (MA). This program aims to study potential solutions for still minimizing the quantity and the hazardousness of final waste, by MA recycling. Indeed, MA recycling can reduce the heat load and the half-life of most of the waste to be buried to a couple of hundred years, overcoming the concerns of the public related to the long-life of the waste. Within this framework, this paper aims to present the most recent progress obtained in CEA on the development of innovative actinide partitioning hydrometallurgical processes in support of their recycling, either in an homogeneous mode (MA are recycled at low concentration in all the standard reactor fuel) or in an heterogeneous mode (MA are recycled at higher concentration in specific targets, at the periphery of the reactor core). Recovery performances obtained on recent tests in high active conditions of the so-called GANEX and DIAMEX-SANEX process will be presented and discussed in light of the potential P&T scenarios. Finally, recent developments regarding the recycling of the sole Am will be presented as well as the results obtained on highly active solutions for this so-called EXAM process. This set of results gives to the French government a portfolio of potential recycling processes which could be separately and progressively implemented if decided.
1992-2017: 25 years of success story on Minor Actinides Partitioning Processes Development
2017
International audienceIn the frame of the successive 1991 and 2006 Waste Management Acts, French government supported a very significant RetD program on partitioning and transmutation of minor actinides (MA) in fast reactors. This program aimed to study potential solutions for still minimizing the quantity and the hazardousness of final waste, by MA recycling. Indeed, MA recycling can reduce the heat load and the radiotoxicity of most of the waste to be buried to a couple of hundred years, overcoming the concerns of the public related to the long-life of the waste. Over the 20 years of development, different types of strategies were studied, from the early multi-stage DIAMEX-SANEX processes to the most recent innovative SANEX, from the grouped extraction of MA thanks to the GANEX process to the most recent sole Americium recycling thanks to the EXAm process. These developments were supported by a robust and long-standing approach allowing successively to screen the potential extract...
Recycling the Actinides, The Cornerstone of Any Sustainable Nuclear Fuel Cycles
Procedia Chemistry, 2012
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.
Scientific Reports
Expanded low-carbon baseload power production through the use of nuclear fission can be enabled by recycling long-lived actinide isotopes within the nuclear fuel cycle. This approach provides the benefits of (a) more completely utilizing the energy potential of mined uranium, (b) reducing the footprint of nuclear geological repositories, and (c) reducing the time required for the radiotoxicity of the disposed waste to decrease to the level of uranium ore from one hundred thousand years to a few hundred years. A key step in achieving this goal is the separation of long-lived isotopes of americium (Am) and curium (Cm) for recycle into fast reactors. To achieve this goal, a novel process was successfully demonstrated on a laboratory scale using a bank of 1.25-cm centrifugal contactors, fabricated by additive manufacturing, and a simulant containing the major fission product elements. Americium and Cm were separated from the lanthanides with over 99.9% completion. The sum of the impurities of the Am/Cm product stream using the simulated raffinate was found to be 3.2 × 10 −3 g/L. The process performance was validated using a genuine high burnup used nuclear fuel raffinate in a batch regime. Separation factors of nearly 100 for 154 Eu over 241 Am were achieved. All these results indicate the process scalability to an engineering scale.
Characterization of metallic fuel for minor actinides transmutation in fast reactor
Progress in Nuclear Energy, 2016
The METAPHIX programme is a collaboration between the Central Research Institute of Electric Power Industry (CRIEPI, Japan) and the Joint Research Centre-Institute for Transuranium Elements (JRC-ITU) of the European Commission dedicated to investigate the safety and effectiveness of a closed nuclear fuel cycle based on Minor Actinides (MA: Np, Am, Cm) separation from spent fuel, incorporation in metal alloy fuel and transmutation in fast reactor. Nine Na-bonded experimental pins of metal alloy fuel were prepared at ITU and irradiated at the Phenix reactor (CEA, France) achieving 2.5 at.%, 7 at.% and 10 at.% burn-up. Four metal alloy compositions were irradiated: U-Pu-Zr used as fuel reference, U-Pu-Zr þ 5 wt.% MA, U-Pu-Zr þ 2 wt.% MA þ 2 wt.% Rare Earths (RE: Nd, Y, Ce, Gd), and þ5 wt.% MA þ 5 wt.% RE, respectively. RE reproduce the expected output of a pyrometallurgical reprocessing facility. Post Irradiation Examination is performed using several techniques, covering properties ranging from the macroscopic morphology of the fuel matrix to the microanalysis of phases and elemental redistribution/segregation. The irradiated fuel is characterized by many phases occurring along the fuel radius. The fuel underwent large redistribution of the fuel constituents (U, Pu, Zr) and many secondary phases are present with a variety of compositions. The distribution of phases in the irradiated fuel containing minor actinides and rare earths is essentially similar to that observed in the basic ternary alloy fuel.
SACSESS – the EURATOM FP7 project on actinide separation from spent nuclear fuels
Nukleonika, 2015
Recycling of actinides by their separation from spent nuclear fuel, followed by transmutation in fast neutron reactors of Generation IV, is considered the most promising strategy for nuclear waste management. Closing the fuel cycle and burning long-lived actinides allows optimizing the use of natural resources and minimizing the long-term hazard of high-level nuclear waste. Moreover, improving the safety and sustainability of nuclear power worldwide. This paper presents the activities striving to meet these challenges, carried out under the Euratom FP7 collaborative project SACSESS (Safety of Actinide Separation Processes). Emphasis is put on the safety issues of fuel reprocessing and waste storage. Two types of actinide separation processes, hydrometallurgical and pyrometallurgical, are considered, as well as related aspects of material studies, process modeling and the radiolytic stability of solvent extraction systems. Education and training of young researchers in nuclear chemis...
Nuclear Engineering and Design, 2011
A study was conducted to evaluate the feasibility of minor actinide (MA) transmutation in light water reactors (LWR). The purpose of this work was to provide a guide for future investigations into MA transmutation in LWR. This work considered the effects of various Am/Cm separation efficiencies as well as homogeneous and heterogeneous MA bearing fuel assemblies. The MA content was introduced into the reactor as mixed oxide plus minor actinide (MOX + MA) fuel. Three Am/Cm separation efficiencies were independently considered: 99.9%, 99.0%, and 90.0%. In order to evaluate the feasibility of MA transmutation, the fuel performance of the various assemblies and core designs, as well as their respective safety related parameters, were calculated. The reduction of the burden of high level waste (HLW) motivated the investigation of MA transmutation. It was found that the MA bearing fuel assemblies and their subsequent core designs were able to perform within the safety limits required as well as achieving similar burnups to a UO 2 core. The Am transmutation rates were ∼40% for the homogeneous assemblies and up to 68% for the MA targets in the heterogeneous assemblies after the described burnup, however, there was a significant amount of Cm produced during burnup. This Cm production was due to the more favorable neutron capture reaction over fission for Am in the thermal spectrum. Future work should examine the benefits of Am transmutation at the expense of large Cm production rates.
Progress in Particle and Nuclear Physics, 2011
If nuclear power becomes a sustainable source of energy, a safe, robust, and acceptable solution must be pursued for existing and projected inventories of high-activity, longlived radioactive waste. Remarkable progress in the field of geological disposal has been made in the last two decades. Some countries have reached important milestones, and geological disposal (of spent fuel) is expected to start in 2020 in Finland and in 2022 in Sweden. In fact, the licensing of the geological repositories in both countries is now entering into its final phase. In France, disposal of intermediate-level waste (ILW) and vitrified high-level waste (HLW) is expected to start around 2025, according to the roadmap defined by an Act of Parliament in 2006. In this context, transmutation of part of the waste through use of advanced fuel cycles, probably feasible in the coming decades, can reduce the burden on the geological repository. This article presents the physical principle of transmutation and reviews several strategies of partitioning and transmutation (P&T). Many recent studies have demonstrated that the impact of P&T on geological disposal concepts is not overwhelmingly high. However, by reducing waste heat production, a more efficient utilization of repository space is likely. Moreover, even if radionuclide release from the waste to the environment and related calculated doses to the population are only partially reduced by P&T, it is important to point out that a clear reduction of the actinide inventory in the HLW definitely reduces risks arising from less probable evolutions of a repository (i.e., an increase of actinide mobility in certain geochemical situations and radiological impact by human intrusion).
Malaysian Journal of Fundamental and Applied Sciences
The evaluation of RSG-GAS research reactor for transmutation reactor was proposed to study its effectiveness to transmute minor actinides (MA), specifically Am-241, to support geologic storage/disposal. The Am-241 radionuclide was assumed to be discharged from 1000MWe PWR’s spent fuel. The mass of Am-241 discharged from within a year operation of 1000MWe PWR was 1.65E+03 gram, while the optimum Am-241 mass which can be transmuted in RSG-GAS - and still meet the safety requirements of reactivity - was 8.0E+03 gram. This was equivalent to about cumulative Am-241 discharged from 5 units of 1000MWe PWR. In 10 cycles of RSG-GAS operation (about 2 years), the remaining of Am-241 is only about 100 grams. The ratio of Am-241 transmuted (8.0E+03 gram) and Am-241 produced in the RSG-GAS core (1.98E-02 gram) within 1-year operation shows the effectiveness of RSG-GAS as a transmutation reactor.
Actinides recycling within closed fuel cycles
Nuclear Engineering International
The global energy context argues in favour of the sustainable development of nuclear energy, since the demand for energy will significantly increase, while resources will tend to get scarcer. Reprocessing and recycling nuclear fuel, together with fast reactors, can help nuclear power to conserve existing uranium resources and reduce the nuclear waste burden for future generations.