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[en] In France the complete closure of the fuel cycle can be reached in 3 steps. The first step relies on the improvement of the present fuel cycle by implementing the use of reprocessed uranium (URT) and by enlarging the use of MOX fuel from 900 MW to 1300 MW PWR. The first loading of URT fuel is planned in 2023. The second step will be the multi-recycling of plutonium. The loading of a test fuel assembly with multi-recycled Pu in a PWR core could be made in 2025-2028 and the industrial deployment may be made in 2040 at the soonest. The third step implies the development of a fleet of fast reactors that will allow a limitless recycling of spent fuels and no necessity of using enriched natural uranium. (A.C.)
[en] A recent Evaluation and Screening (E/S) study of nuclear fuel cycle options was conducted by grouping all potential options into 40 Evaluation Groups (EGs) based on similarities in fundamental physics characteristics and fuel cycle performance. Through a rigorous evaluation process considering benefit and challenge metrics, 4 of these EGs were identified by the E/S study as 'most promising'. All 4 involve continuous recycle of U/Pu or U/TRU with natural uranium feed in fast critical reactors. However, these most promising EGs also include fuel cycle groups with variations on feed materials, neutron spectra, and reactor criticality. Therefore, the impacts of the addition of natural thorium fuel feed to a system that originally only used natural uranium fuel feed, using an intermediate spectrum instead of a fast spectrum, and using externally-driven systems versus critical reactors were evaluated. It was found that adding thorium to the natural uranium feed mixture leads to lower burnup, higher mass flows, and degrades fuel cycle benefit metrics (waste management, resource utilization, etc.) for fuel cycles that continuously recycle U/Pu or U/TRU. Adding thorium results in fissions of 233U instead of just 239Pu and in turn results in a lower average number of neutrons produced per absorption (η) for the fast reactor system. For continuous recycling systems, the lower η results in lower excess reactivity and subsequently lower achievable fuel burnup. This in turn leads to higher mass flows (fabrication, reprocessing, disposal, etc.) to produce a given amount of energy and subsequent lower metrics performance. The investigated fuel cycle options with intermediate spectrum reactors also exhibited degraded performance in the benefit metrics compared to fast spectrum reactors. Similarly, this is due to lower η values as the spectrum softens. The best externally-driven systems exhibited similar performance as fast critical reactors in terms of mass flows, but they face much greater challenges, including higher waste generation and higher economic and development costs associated with the external neutron supply. Therefore, any fuel cycle option within the most promising EGs that include thorium in the feed mixture, involves intermediate spectrum reactors, or uses externally-driven systems will be less promising than the reference fast spectrum critical reactor with only natural uranium feed. (authors)
[en] The development of advanced thorium-based nuclear system raises new requirements on nuclear data. The multi-group data file of critical nuclides in the thorium-uranium recycle is the foundation of physical design, analysis and calculation of the reactor core. Based on authoritative nuclear data processing code NJOY, this paper obtains a WIMS format multi-group cross section data files through processing the ENDF/B-VII.1 evaluation nuclear data file, uses the specific update maintenance procedure WILLIE to get a WIMS format data file, and conducts a series of critical benchmarks on the data file using the multi-group reactor core calculation code WIMSD5B. The results show that the computed results of the WIMS file based on the processing of ENDF/B-VII.1 are basically the same as those of the latest WIMS-D file published on the websites of the 'WIMS-D' library updating project (WLUP) with higher accuracy and reliability than those of the shipped WIMS-D file of the WIMSD5B code. Furthermore, the average deviation of the new WIMS file performing in the validation of 16 thorium-uranium cycle benchmarks is 0.225 3% smaller than that of the old WIMS file. (authors)
[en] The technique of evaluation of the multiplication factors and reactivity characteristics of fast reactors operating in the mode of multiple refueling is presented. We describe and apply the calculation method. The results demonstrate that fuel composition comes into equilibrium concentration in the multiple refueling reactor operation mode. If initial loads were based on plutonium from spent fuel of thermal and fast power reactors, equilibrium was achieved with twice repeated refueling. For initial fuel loads based on highly enriched uranium nitride or uranium-plutonium nitride fuel with high enrichment of 239Pu, equilibrium is reached after 4-5 refuelings
[en] The paper deals with the evaluation of fuel handling in fast reactors in the closed nuclear fuel cycle. To solve these problems, the REPRORYV program code has been developed. It simulates the nuclide streams in out-of-reactor stages of the closed fuel cycle. Existed verified code JARFR is used for the calculation of neutron-physical characteristics of the core. Various options for nuclide streams are considered with a representative full-scale model of a fast reactor with sodium-cooled high-power. The changes of multiplication factor and mass of plutonium in the closed nuclear fuel cycle for a Russian BN-type fast reactor with use of the REPRORYV code are evaluated. Different scenarios of fuel reprocessing assuming the removing or retaining of actinides, taking into account various plutonium losses on reprocessing steps were considered. The questions of influence of the initial content of plutonium in nitride fuel (Pu-U-N) and the impact of the initial parameters to the possibility of fuel self-sufficient mode of the reactor during the whole period of its operation are studied
[en] The investigation of the thorium fuel cycle (ThFC) is a collaborative INPRO (International Project on Innovative Nuclear Reactors and Fuel Cycles) activity within its main area on global vision on sustainable nuclear energy for the 21st century. The current publication reports on the sustainability of nuclear power by re-examining the potential of thorium-based fuel cycles to support future large scale deployment of nuclear energy systems by increasing the availability of nuclear material. Special attention is paid to the thorium fuel cycle from the point of view of economics and proliferation resistance.
[en] One of the key objectives of the U.S. Department of Energy (DOE) Nuclear Energy Research/development road-map is the development of sustainable nuclear fuel cycles that can improve natural resource utilization and provide solutions to the management of nuclear wastes. Recently, an evaluation and screening (ES) of fuel cycle systems has been conducted to identify those options that provide the best opportunities for obtaining such improvements and also to identify the required research and development activities that can support the development of advanced fuel cycle options. In order to evaluate and screen fuel cycle systems in the ES study, nine criteria were used including Development and Deployment Risk (DDR). More specifically, this criterion was represented by the following metrics: Development time, development cost, deployment cost from prototypic validation to first-of-a-kind commercial, compatibility with the existing nuclear fuel cycle infrastructure, existence of regulations for the fuel cycle and familiarity with licensing, and existence of market incentives and/or barriers to commercial implementation of fuel cycle processes. Given the comprehensive nature of the study, a systematic approach was needed to determine metric data for the DDR criterion. As would be expected, the Evaluation Group representing the once-through use of uranium in thermal reactors is always the highest ranked fuel cycle Evaluation Group for this DDR criterion. Evaluation Groups that consist of once-through fuel cycles that use existing reactor types are consistently ranked very high. The highest ranked limited and continuous recycle fuel cycle Evaluation Groups are those that recycle Pu in thermal reactors. The lowest ranked fuel cycles are predominately continuous recycle single stage and multi-stage fuel cycles that involve TRU and/or U233 recycle. (authors)
[en] The Fuel Cycle Options (FCO) campaign in the U.S. DOE Fuel Cycle Research and Development Program recently completed a detailed evaluation and screening of nuclear fuel cycles (report available at www.inl.gov). The comprehensive study identified promising fuel cycle options that offer the potential for substantial improvement compared to the current U.S. fuel cycle. This paper describes insights from the study and the use of the results for current fuel cycle analysis activities. The insights obtained from the study prompted questions about the usefulness of minor actinide recycle and the relative potential of thorium-based fuel cycles compared to uranium-based fuel cycles. The FCO campaign is conducting analyses exploring these issues as well as the potential transition to such fuel cycles to identify the challenges and the timing for critical decisions that would need to be made, including investigation of concerns such as the effects of a temporary lack of recycle fuel resources or supporting infrastructure. These studies are part of an overall analysis approach designed to provide information to the U.S. DOE Office of Nuclear Energy decision-making process for R/D directions. (author)
[en] The waste management strategy of partitioning and transmutation is currently the cutting edge development of nuclear technologies, which has been intensively researched over the last several decades, as it is highlighted in the following two excerpts on the history of partitioning and transmutation given below.
[en] The French fleet of reactors is made up of 58 pressurized water reactors (PWR). Before being loaded in the core of a reactor, the nuclear fuel comes from a long process, beginning in the mine and going through enrichment and the manufacturing of fuel assemblies. After a 4-year long irradiation in reactor, used fuels are unloaded, separated and packaged for final disposal. Separation allows the recovery of plutonium and uranium and their re-use as nuclear fuel in reactors. This article details every stage of nuclear fuel from mining to disposal via reprocessing. A graph shows how in 2013, the recovery of plutonium allowed the fabrication of 100 tonnes of mixed uranium and plutonium oxides fuel (MOX) and the recovery of uranium allowed the fabrication of 70 tonnes of re-enriched fuel (URE). The total amount of nuclear fuel required to feed 58 reactors is 1000 tonnes a year. (A.C.)