Applicability study of the photofission based nuclear material isotopic composition measurement method on the Thorium-Uranium system

A principle of new nondestructive assay (NDA) technique based on the photofission reaction ratio (PFRR) has been developed, which is aimed at measuring the isotopic composition of nuclear fuel materials without relying on their self-generated neutron information. The feasibility of the PFRR method was validated in the 235U-238U system previously. However, applicability of the PFRR method in the other material is not yet validated. In this study, applicability of PFRR method to the 232Th-233U system was confirmed, PFRR method showed good reproducibility of predicted value of 232Th and 233U isotopic composition.