A comparison of curium, neptunium and americium transmutation feasibility

Abstract

Minor actinides transmutation is the process of decreasing the long term radiotoxicity of the nuclear spent fuel by submitting it to a neutron flux so as to achieve fission of the heavy nuclides concerned. In the case of a closed fuel cycle, minor actinides are the main contributors to the spent fuel radiotoxicity after a few centuries. The isotopic vector of the minor actinides feed to be transmuted depends heavily on the fuel cycle considered: PWRs with UOX fuels will mainly lead to neptunium and americium production while MOX fueled reactors will produce mainly americium and curium. Americium is the main element currently considered for transmutation due to its relatively short half-life and important production. On the other hand, neptunium is seen as a secondary candidate for transmutation due to its very long half life and low activity while Curium has transmutation is generally ruled out due to the important activity of curium isotopes. Two modes of transmutation in fast reactors are generally opposed, namely the homogeneous approach in which minor actinides are directly mixed with the fuel while in the heterogeneous approach, the minor actinides are loaded in dedicated targets. It is shown in this paper that the impacts on the fuel cycle of heterogeneous americium transmutation are similar to the one of homogeneous curium transmutation. It is further shown that given the quantities of curium in the fuel cycle, only a limited number of reactors would be required to effectively transmute the curium production of fast reactors with americium bearing blankets. Curium transmutation thus appears a feasible option in a completely closed fuel cycle without significantly higher fuel cycle impacts than with only americium transmutation. It is finally verified that neptunium transmutation can be achieved regardless of the approach considered.

Periodic trends and complexation chemistry of tetravalent actinide ions with a potential actinide decorporation agent 5‐LIO(Me‐3,2‐HOPO): A relativistic density functional theory exploration

“…It requires an extra level of safety measures and the use of proper personal protective equipment (PPE) due to the inherent radiological and chemical toxicity of actinides . Among actinides, Th, U, and Pu are extensively used as nuclear fuel material in nuclear power plants while Np, Am, and Cm are produced during the reactor operation within the fuel and become important in the reprocessing of used nuclear fuels . Despite of extensive safety features, inadvertent release of actinides in the working environment remains a global concern as it poses significant health risks to the working personnel.…”

Application of Minor Actinides as Burnable Poisons in Sodium Fast Reactors

“…As discussed in the previous paper (Guo et al, 2018), the candidates for the burnable poison should have a negative contribution to the chain reaction at the beginning of irradiation and this negative contribution must be reduced under irradiation or even be converted into positive contribution. The contribution to chain reaction of isotope i can be defined by plutonium equivalence w i as (Bussac and Reuss, 1978):…”

“…A core similar to the one described in our previous paper (Guo et al, 2018) and known as SFR-V2B SFR-V2B (3600 MWth) has been chosen as the target core in this work to apply minor Am and by-products 4 actinides as burnable poison. This core has been deeply studied to achieve objectives defined for Generation-IV reactors (Mignot et al, 2008;Sciora et al, 2009).…”

“…In our previous paper, boron carbide coupled with moderator is applied as burnable poison (BP) in a sodium fast reactor (SFR) to reduce core excess reactivity at the beginning of an equilibrium cycle (BOEC) and thus to reduce the effect of an inadvertent control rod withdrawal (CRW) (Guo et al, 2018). Now we seek to investigate a new burnable poison design.…”

“…As plutonium is re-used in a closed fuel cycle, long-term behavior of nuclear waste is driven by minor actinides (MA) (Kooyman et al, 2018), which challenges the recycling process and long-term underground storage because of their long half-life, high activity and important decay heat. The main minor actinides from current spent fuel are 237 Np, 241 Am and 243 Am.…”