Abstract
The mass flow of plutonium and minor actinides is calculated for a future light water reactor-fast breeder reactor (LWR-FBR) transition scenario, in which a certain scale of power generation by LWRs is continued for a long period before the replacement by FBRs begins. The burnup of the LWR spent fuel is considered to be higher than the current standard. It is assumed that all the plutonium and minor actinides recovered from LWRs are used for the start-up and feed of metal fuel commercial FBRs to replace those LWRs that reach the lifetime. The results show that the accumulated plutonium and minor actinides from the LWRs can be consistently consumed without further accumulation, by gradually establishing the same scale of the FBR power generation and the associated fuel cycle. The minor actinides content in the standard FBR fuel that is sufficient to realize this scenario is estimated to be about 2 wt%. This result indicates that if the FBR era is to come in the future, the extended LWR era causes no significant problem in terms of the consumption of the accumulated transuranic.