The role of Z-pinch fusion transmutation of waste in the nuclear fuel cycle (original) (raw)
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Fusion transmutation of waste: design and analysis of the in-zinerator concept
2006
Due to increasing concerns over the buildup of long-lived transuranic isotopes in spent nuclear fuel waste, attention has been given in recent years to technologies that can burn up these species. The separation and transmutation of transuranics is part of a solution to decreasing the volume and heat load of nuclear waste significantly to increase the repository capacity. A fusion neutron source can be used for transmutation as an alternative to fast reactor systems. Sandia National Laboratories is investigating the use of a Z-Pinch fusion driver for this application. This report summarizes the initial design and engineering issues of this "In-Zinerator" concept. Relatively modest fusion requirements on the order of 20 MW can be used to drive a sub-critical, actinide-bearing, fluid blanket. The fluid fuel eliminates the need for expensive fuel fabrication and allows for continuous refueling and removal of fission products. This reactor has the capability of burning up 1,280 kg of actinides per year while at the same time producing 3,000 MW th . The report discusses the baseline design, engineering issues, modeling results, safety issues, and fuel cycle impact.
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.
Minor actinide transmutation potential of modified PROMETHEUS fusion reactor
Journal of fusion energy, 2004
This study presents the investigation of the burning and/or transmutation (B/T) of minor actinides (MAs) in the modified PROMETHEUS-H fusion reactor. The calculations were performed for an operation period (OP) of up to 10 years by 75% plant factor (g) under a neutron wall load (P) of 4.7 MW/m 2. In order to incinerate and transmute the MAs effectively, the transmutation zone (TZ) containing the mixture of MA nuclides, discharged from the pressured water reactor (PWR)-MOX spent fuel, was located in the modified blanket of the PROMETHEUS-H fusion reactor. Two different blanket modifications were considered, (the Models A and B). The MA mixture was spherically prepared and cladded with SiC to prevent fission products from contaminating coolant and the MAs from contacting coolant. Helium was selected for the nuclear heat transfer in the TZ. The effect of the MA volume fraction in the TZ on the B/T was also investigated. The results bring out that the MAs are converted by the transmutation rather than the incineration. Both models can reduce significantly the effective half-lives of the MA nuclides by burning and/or transmuting these nuclides, and at the same time produce substantial electricity in situ.
LWR spent fuel transmutation with fusion-fission hybrid reactors
Progress in Nuclear Energy, 2013
In this paper the transmutation of light water reactors (LWR) spent fuel is analyzed. The system used for this study is the fusion-fission transmutation system (FFTS). It uses a high energy neutron source produced with deuterium-tritium fusion reactions, located in the center of the system, which is surrounded by a fission region composed of nuclear fuel where the fissions take place. In this study, the fuel of the fission region is obtained from the recycling of LWR spent fuel. The MCNPX Monte Carlo code was used to setup a model of the FFTS. Two fuel types were analyzed for the fissile region: the mixed oxide fuel (MOX), and the inert matrix fuel (IMF). Results show that in the case of the MOX fuel, an important Pu-239 breeding is achieved, which can be interesting from the point of view of maximal uranium utilization. On the contrary, in the case of the IMF fuel, high consumption of Pu-239 and Pu-241 is observed, which can be interesting from the point of view of non-proliferation issues. A combination of MOX and IMF fuels was also studied, which shows that the equilibrium of actinides production and consumption can be achieved. These results demonstrate the versatility of the fusion-fission hybrid systems for the transmutation of LWR spent fuel.
Reprocessing free nuclear fuel production via fusion fission hybrids
Fusion Engineering and Design, 2012
Fusion fission hybrids, driven by a copious source of fusion neutrons can open qualitatively "new" cycles for transmuting nuclear fertile material into fissile fuel. A totally reprocessing-free (ReFree) Th 232-U 233 conversion fuel cycle is presented. Virgin fertile fuel rods are exposed to neutrons in the hybrid, and burned in a traditional light water reactor, without ever violating the integrity of the fuel rods. Throughout this cycle (during breeding in the hybrid, transport, as well as burning of the fissile fuel in a water reactor) the fissile fuel remains a part of a bulky, countable, ThO 2 matrix in cladding, protected by the radiation field of all fission products. This highly proliferation-resistant mode of fuel production, as distinct from a reprocessing dominated path via fast breeder reactors (FBR), can bring great acceptability to the enterprise of nuclear fuel production, and insure that scarcity of naturally available U 235 fuel does not throttle expansion of nuclear energy. It also provides a reprocessing free path to energy security for many countries. Ideas and innovations responsible for the creation of a high intensity neutron source are also presented.
Nuclear Engineering and Design, 2018
The performance of the fusion-fission hybrid system based on the molten salt (flibe) blanket, driven by a plasma based fusion device, was analyzed by comparing transmutation scenarios of actinides extracted from the LWR (Sweden) and RBMK (Lithuania) spent nuclear fuel in the scope of the EURATOM project BRILLIANT. The IAEA nuclear fuel cycle simulation system (NFCSS) has been applied for the estimation of the approximate amount of heavy metals of the spent nuclear fuel in Sweden reactors and the SCALE 6 code package has been used for the determination of the RBMK-1500 spent nuclear fuel composition. The total amount of trans-uranium elements has been estimated in both countries by 2015. Major parameters of the hybrid system performance (e.g., k scr , k eff , Φ n (E), equilibrium conditions, etc.) have been investigated for LWR and RBMK trans-uranium transmutation cases. Detailed burn-up calculations with continuous feeding to replenish the incinerated trans-uranium material and partial treatment of fission products were done using the Monteburns (MCNP + ORIGEN) code system. About 1.1 tons of spent fuel trans-uranium elements could be burned annually with an output of the 3 GW th fission power, but the equilibrium stage is reached differently depending on the initial trans-uranium composition. The radiotoxicity of the remaining LWR and RBMK transmuted waste after the hybrid system operation time has been estimated.
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.
Fusion Science and Technology, 2012
The performances of three different types of innovative transmutation systems have been investigated in order to assess in a comparative way their potential to manage nuclear waste arising in a geographical region, where different countries have different policies with respect to nuclear energy development, but share the objective of a common optimized waste management strategy in order to minimize the waste masses sent to a geological repository. The three systems are 1) a critical low conversion ratio fast reactor (LCFR); 2) an accelerator driven system (ADS) and 3) a hybrid fissionfusion system (FFH). In order to simplify the comparison, the three systems have been loaded with comparable fuels, in particular with the same Pu to Minor Actinides (MA) ratio. A waste management scenario study has been performed: the results show that, apart from the technological readiness of each single option, the performances, in terms e.g. of time needed to eliminate specific spent fuel inventories or in terms of reduction of decay heat and radiotoxicity in a deep geological repository, are rather comparable.