Neutronic Assessment of Transmutation Target Compositions in Heterogeneous Sodium Fast Reactor Geometries (original) (raw)
Related papers
2019
The Russian Federation is developing a number of technologies within the «Proryv» project for closing the nuclear fuel cycle utilizing mixed (U-PuMA) nitride fuel. Key objectives of the project include improving fast reactor nuclear safety by minimizing reactivity changes during fuel operating period and improving radiological and environmental fuel cycle safety through Pu multi-recycling and MA transmutation. This advanced technology is expected to allow operating the reactor in an equilibrium cycle with a breeding ratio equaling approximately 1 with stable reactivity and fuel isotopic composition. Nevertheless, to reach this state the reactor must still operate in an initial transient state for a lengthy period (over 10 years) of time, which requires implementing special measures concerning reactivity control. The results obtained from calculations show the possibility of achieving a synergetic effect from combining two objectives. Using MA reprocessed from thermal reactor spent fuel in initial fuel loads in FR ensures a minimal reactivity margin during the entire fast reactor fuel operating period, comparable to the levels achieved in equilibrium state with any kind of relevant Pu isotopic composition. This should be combined with using reactivity compensators in the first fuel micro-campaigns. In the paper presented are the results of simulation of the overall life cycle of a 1200 MWe fast reactor, reaching equilibrium fuel composition, and respective changes in spent fuel nuclide and isotopic composition. It is shown that MA from thermal and fast reactors spent fuel can be completely utilized in the new generation FRs without using special actinide burners.
Applied Radiation and Isotopes, 1995
A deep geological repository for safe long-term storage of long-lived radioactive materials (waste) arising from nuclear fuel irradiation in reactors is a need generally accepted, whatever the strategy envisaged for further use of the irradiated fuel (e.g. : reprocessing and re-use of uranium and plutonium ; no reprocessing and final disposal).
Spent Nuclear Fuel and Alternative Methods of Transmutation
Spent Nuclear Fuel and Accelerator-Driven Subcritical Systems
The chapter deals with the status of the spent nuclear fuel and accumulation of unspent nuclear fuel world over. Its fertile, fissile and fission product components are also discussed along with their applications and various methods of reprocessing the SNF. International situation related to reprocessing, security aspects arising from the SNF, and the fissile components along with its handling at individual national level are also summarized. 1.1 Spent and Unspent Nuclear Fuel and the Nuclear Waste Spent nuclear fuel (SNF) is the nuclear fuel that is irradiated in a power reactor. A few percent of this is utilized in power generation, and a very large part is left behind as a radiotoxic material at the time of discharge of a reactor. In the SNF major actinides, U and Pu are 95-96 and 1%, respectively. Minor actinides (Np, Am, and Cm) are 0.1%, short-lived fission products (FP) are 3-4%, and long-lived FPs are 0.1%. Different composition elements pose different challenges for disposition of SNF. In fact, unspent nuclear fuel (UNF) is of high concern because its components can be utilized for nuclear energy or other atomic devices with least efforts.
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.
Isotopic Transmutation and Fuel Burnup in BN-600 Hybrid Fast Reactor Core
2012
BN-600 fast reactor core was modeled using MCNPX computer code. The core configuration and material composition, for the hybrid design, was simulated in this model. The power generated in different zones was determined and the results were compared with published results and found acceptable. Isotopes transmutations in various zones were estimated. The uranium isotopes are major contributors to power production in this reactor, the probability of plutonium incineration will increase with the increase in the use of MOX oxide. The transmutation of minor actinides is not obvious in this configuration.
Multi-group analysis of Minor Actinides transmutation in a Fusion Hybrid Reactor
EPJ Nuclear Science and Technology, 2023
New nuclear technologies are currently being study to face High Level Waste treatment and disposal issues. Generally, GEN-IV fission Fast Reactors (FR) are considered the waste-burners of the future. In fact, a fast flux turns out to be the best choice for actinides irradiation in critical reactors because of favorable cross section conditions. Differently, Fusion Fission Hybrid Reactors (FFHR) are futuristic devices based on the combination of fusion and fission systems and could represent an alternative to FRs. In such systems, the choice spectrum of the neutron flux that irradiates HLW may be non-obvious due to some operational constraints which have to be considered. To design and optimize these systems as waste-burners, one should fully understand the transmutation dynamics occurring into the fission region. A multi-energy-group analysis by FISPACT-II code has been set to analyze the conversion processes in scenarios characterized by different neutron energy spectra and fluences. The results of this study show that, despite fast fluxes are characterized by better behaviors in terms of radiotoxicity treatment, the difficulties of reaching high reaction yields may require solutions involving moderators or broadened neutron fluxes to increase the reactions probabilities and, consequently, actinides mass conversion yield.
Computational Neutronics Methods and Transmutation Performance Analyses for Fast Reactors
2007
The once-through fuel cycle strategy in the United States for the past six decades has resulted in an accumulation of Light Water Reactor (LWR) Spent Nuclear Fuel (SNF). This SNF contains considerable amounts of transuranic (TRU) elements that limit the heat and dose capacity of the current planned repository strategy. A possible way of maximizing the utilization of the repository is to separate the TRU from the LWR SNF through a process such as UREX+1a, and convert it into fuel for a fast-spectrum Advanced Burner Reactor (ABR). The key advantage in this scenario is the assumption that recycling of TRU in the ABR (through pyroprocessing or some other approach), along with a low capture-to-fission probability in the fast reactor's high-energy neutron spectrum, can effectively decrease the decay heat and toxicity of the waste being sent to the repository. The decay heat and toxicity reduction can thus minimize the need for multiple repositories. This report summarizes the work performed by the fuel cycle analysis group at the Idaho National Laboratory (INL) to establish the specific technical capability for performing fast reactor fuel cycle analysis and its application to a high-priority ABR concept. The high-priority ABR conceptual design selected is a metallic-fueled, 1000 MWth SuperPRISM (S-PRISM)-based ABR with a conversion ratio of 0.5. Results from the analysis showed excellent agreement with reference values. The independent model was subsequently used to study the effects of excluding curium from the transuranic (TRU) external feed coming from the LWR SNF and recycling the curium produced by the fast reactor itself through pyroprocessing. Current studies to be published this year focus on analyzing the effects of different separation strategies as well as heterogeneous TRU target systems.
Nuclear Energy and Technology, 2022
In terms of nuclear raw materials, the issue of involving thorium in the fuel cycle is hardly very relevant. However, in view of the large-scale nuclear power development, the use of thorium seems to be quite natural and reasonable. The substitution of traditional uranium-plutonium fuel for uranium-thorium fuel in fast neutron reactors will significantly reduce the production of minor actinides, which will make it attractive for the transmutation of long-lived radioactive isotopes of americium, curium and neptunium that have already been and are still being accumulated. Due to the absence of uranium-233 in nature, the use of thorium in the nuclear power industry requires a closed fuel cycle. At the initial stage of developing the uranium-thorium cycle, it is proposed to use uranium-235 instead of uranium-233 as nuclear fuel. Studies have been carried out on the transmutation of minor actinides in a fast neutron reactor in which the uranium-thorium cycle is implemented. Several optio...
Annals of Nuclear Energy, 2013
The present paper compares the reactor physics and transmutation performance of sodium-cooled Fast Reactors (FRs) for TRansUranic (TRU) burning with thorium (Th) or uranium (U) as fertile materials. The 1000 MWt Toshiba-Westinghouse Advanced Recycling Reactor (ARR) conceptual core has been used as benchmark for the comparison. Both burner and breakeven configurations sustained or started with a TRU supply, and assuming full actinide homogeneous recycle strategy, have been developed. State-ofthe-art core physics tools have been employed to establish fuel inventory and reactor physics performances for equilibrium and transition cycles. Results show that Th fosters large improvements in the reactivity coefficients associated with coolant expansion and voiding, which enhances safety margins and, for a burner design, can be traded for maximizing the TRU burning rate. A trade-off of Th compared to U is the significantly larger fuel inventory required to achieve a breakeven design, which entails additional blankets at the detriment of core compactness as well as fuel manufacturing and separation requirements. The gamma field generated by the progeny of U-232 in the U bred from Th challenges fuel handling and manufacturing, but in case of full recycle, the high contents of Am and Cm in the transmutation fuel impose remote fuel operations regardless of the presence of U-232.