The realization of a zero-carbon electricity system is of vital importance to a future zero-carbon energy system and society. Nuclear power is expected to contribute to the realization of a zero-carbon electricity system much more than intermittent, complicated and costly renewable energy in the future in Japan. Therefore, in the present study, nuclear power development for a future zero-carbon energy system was studied through scenario analysis. The study was conducted in three steps to (i) estimate future electricity demand and electrical load pattern by 2100; (ii) determine the contribution of nuclear power to the electricity generation based on various constraints; and (iii) test the feasibility of the nuclear-based electricity system in term of supply-demand balance. An integrated computer software platform was developed to conduct the analyses. The analysis results show that Fukushima Accident will not affect nuclear development in Japan greatly from a long term viewpoint. Compared with 2005, the total electricity demand will increase by 50% to 2100. Nuclear power contributes 60%-100% of total electricity production and its capacity factor needs to be enhanced from the present 60-70% to 80-90%. The nuclear power can be supplied from advanced LWR, FBR even fusion technology.