Minor Actinides transmutation in candidate accident tolerant fuel-claddings U3Si2-FeCrAl and U3Si2-SiC.

Highlights • Transmutation of minor actinides in potential accident tolerant fuel-cladding system U3Si2-FeCrAl(SiC) is suggested. • Critical loading concentrations of minor actinides are determined by constraining the cycle length. • Higher transmutation efficiencies are found in candidate accident tolerant fuels comparing with traditional fuel. • One U3Si2-SiC assembly can transmute 237Np produced from six normal assemblies while other properties are kept. Abstract An advanced transmutation method is suggested that the long-lived Minor Actinides (MAs) in the spent fuel can be efficiently transmuted in the candidate Accident Tolerant Fuel (ATF). The transmutation of MAs is investigated through the Monte Carlo simulations in two potential fuel-claddings of ATF, U 3 Si 2 -FeCrAl and U 3 Si 2 -SiC. The critical loadings of MAs are determined through the Linear Reactivity Model (LRM) in order to keep the same reactivity as the current UO 2 -zircaloy system at the End of Cycle (EOC). In all cases, excellent transmutation efficiencies are found for the most important three MAs, 237Np, 241Am, and 243Am, of which the total transmutation rates are around 60%, 90%, and 60%, respectively. If only the longest-lived isotope 237Np is considered, one U 3 Si 2 -SiC assembly can transmute 237Np from six normal assemblies. The loading of MAs has little influences on the neutronic properties, such as the power distributions inside an assembly and inside a fuel rod. The transmutation of MAs in the ATF assembly is shown to be more efficient and safe comparing with the normal assembly, while other important properties are kept, such as the cycle length and the power distribution. [ABSTRACT FROM AUTHOR]