Minor Actinides Transmutation in Candidate Accident Tolerant Fuel-Claddings U3Si2-FeCrAl and U3Si2-SiC

TL;DR

This paper proposes an advanced transmutation method for Minor Actinides in new accident tolerant fuel-claddings, demonstrating high efficiency and safety through Monte Carlo simulations, with potential to significantly reduce long-lived nuclear waste.

Contribution

It introduces a novel transmutation approach for MAs in U3Si2-based ATF, showing improved efficiency and safety over traditional assemblies.

Findings

Transmutation rates for 237Np, 241Am, and 243Am are approximately 60%, 90%, and 60%.

A single U3Si2-SiC assembly can transmute 237Np equivalent to six normal assemblies.

MAs loading minimally affects neutronic properties and cycle length.

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, U3Si2-FeCrAl and U3Si2-SiC. The critical loadings of MAs are determined through the Linear Reactivity Model (LRM) in order to keep the same reactivity as the current UO2-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 U3Si2-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.