A feasibility study on hydrogen production systems using sodium cooled fast breeder reactors has been carried out in Japan Nuclear Cycle Development (JNC). Thermochemical and electrolysis hybrid cycle developed in JNC is one of sulfuric acid cycle without carbon dioxide emission. The process temperature is lowered up to 500deg-C to add SO_3 gas electrolysis to Westinghouse sulfuric acid cycle. In this study, hydrogen production system is designed. Major components of the plant are sketched and designed to be made of steels such as high Si cast iron which has good toughness against sulfuric acid. High hydrogen production efficiency of 42% is achieved with the thermochemical electrolysis hybrid cycle, assuming development of high efficiency electrolysis.
