Transmutation of 129I in a single-fluid double-zone thorium molten salt reactor

Abstract

Herein, we assess the 129I transmutation capability of a 2250-MWt single-fluid double-zone thorium molten salt reactor (SD-TMSR) by considering two methods. One is realized by loading an appropriate amount of 129I before the startup of the reactor, and the amount of 129I during operation is kept constant by online feeding 129I. The other adopts only an initial loading of 129I before startup, and no other 129I is fed online during operation. The investigation first focuses on the effect of the loading of I on the Th-233U isobreeding performance. The results indicate that a 233U isobreeding mode can be achieved for both scenarios for a 60-year operation when the initial molar proportion of LiI is maintained within 0.40% and 0.87%, respectively. Then, the transmutation performances for the two scenarios are compared by changing the amount of injected iodine into the core. It is found that the scenario that adopts an initial loading of 129I shows a slightly better transmutation performance in comparison with the scenario that adopts online feeding of 129I when the net 233U productions for the two scenarios are kept equal. The initial loading of 129I scenario with LiI = 0.87% molar proportion is recommended for 129I transmutation in the SD-TMSR, and can transmute 1.88 t of 129I in the 233U isobreeding mode over 60 years.