Feasibility study on extended operating cycle of the next generation PWR

摘要

It is expected that light water reactors (LWRs) will continue to play a dominant role in the nuclear power generation even after the change of the century. Development of future LWRs suitable for this perspective has been promoted both in Japanand in other countries. This paper focuses on the studies on feasibility of extended operating cycle of the Next Generation PWR, one of the future types of LWRs.First of all, extended operating cycles in oversea countries were studied, and then the operating cycle length suitable for Japanese plants was estimated. Overall feasibility of long operating cycles for the Next Generation PWR of 1, 700MWe level wasstudied from engineering, economic and equipment integrity standpoints in this study. As a result of the studies, the 18 and 24 month operating cycles are proved to be the desirable cycle patterns when the electric demand in Japan is taken into account.Possible economic improvement compared with the current operating cycles (of 15 months at maximum), as well as sufficient technical feasibility of the 24 month cycle, has been confirmed.This paper also points out, as a future objective, that it is desirable to develop fuels with the bornup higher than the current limit of 55 GWd/t and to raise the enrichment limit of 5%.