TRU GENERATION SUPPRESSION BY HALEU FUEL WITH FIXED DISCHARGE BURNUP USING BURNABLE POISON

Abstract

Effects of burnable poison (BP) addition on radiotoxicity by TRU were investigated for FORSETI fuel, which is assumed to be loaded into a BWR plant. Since the purpose of this study was to confirm the relative change in radiotoxicity due to TRU, the weight ratio of TRU was used as an index of the relative magnitude of radiotoxicity. The weight fraction of TRU nuclides with ²³⁵U enrichment from 3.8 wt% to 20 wt% was examined with and without BP. The weight fraction of TRU nuclides in the spent fuel decreased by about 60% for ²³⁸Pu, ²⁴⁰Pu, and ²⁴¹Pu. The results of these nuclides are almost the same between with and without BP. On the other hand, ²³⁹Pu, which is not dominant in the toxicity of TRU, is slightly increased by the addition of BP. The relative difference in TRU weight fraction between with-BP and without-BP by increase of ²³⁵U enrichment does not exceed 20wt% except for ²³⁹Pu.It is desirable to consider the error in the amount of TRU generation when evaluating without BP for analytical simplicity.