Performances of Molten-Salt Fast Reactor with Self-Sustainability

Abstract

A study is performed on a molten salt fast reactor （ MSFR ） of 1.5 GWe output. The reactor is started up by using transuranium elements reprocessed from spent fuel of a BWR. The fuel salt of the reactor is the mixed fluoride salt NaF – KF – UF 4 – TRUF 3 , which is reprocessed almost continuously by an oxide-precipitation process during the reactor operation. By performing calculations using the nuclear analysis code PIJ – BURN in SRAC2006 and the nuclear data file of JENDL – 3.3, the following re-sults are obtained. （ 1 ） The burn-up characteristics of the reactor are mainly determined by the uranium inventory （ U inv ） in the reactor and the reprocessing cycle （ L rep ） , which is the time interval necessary to reprocess all the fuel salt in the primary loop. （ 2 ） A large U inv and short L rep enhance the breeding performance of the reactor. （ 3 ） The period necessary to keep the radioactive waste under control will be about 400 years in the case of L rep longer than 400 efpd. （ 4 ） Power stations consisting of 20 MSFRs （ total output of 30 GWe ） can operate for 600 years by utilizing 14,000 t of uranium obtained from the spent fuel of LWRs in Japan.