Development of a new thermochemical and electrolytic hybrid hydrogen production system for sodium cooled FBR

Nakagiri, Toshio  ; Kase, Takeshi ; Kato, Shoichi ; Aoto, Kazumi 

A new thermo-chemical and electrolytic hybrid hydrogen production system in lower temperature range is newly proposed by the Japan Atomic Energy Agency (JAEA) to realize the hydrogen production from water by using the heat generation of sodium cooled Fast Breader Reactor (FBR). The system is based on sulfuric acid (HSO) synthesis and decomposition process developed earlier (Westinghouse process), and sulfur trioxide (SO) decomposition process is facilitated by electrolysis with ionic oxygen conductive solid electrolyte to reduce the operation temperature 200-300 C lower than Westinghouse process. SO decomposition was confirmed experimentally, and theoretical thermal efficiency was evaluated. Furthermore, hydrogen production experiments to substantiate the whole process were performed. Stable hydrogen and oxygen production were observed in the experiments, and maximum duration of the experiments was about 5 hours.