UNIVERSALLY APPLICABLE DESIGN CONCEPT OF STABLY CONTROLLING AN HTGR-HYDROGEN PRODUCTION SYSTEM

An HTGR-hydrogen production system should be designed to have stable c ontrollability because of a large difference in thermal dynamics betwe en reactor and hydrogen production system and such a control design co ncept should be universally applicable to a variety of hydrogen produc tion processes by the use of nuclear heat from HTGR. A transient respo nse analysis of an HTGR-steam reforming hydrogen production system sho wed that a steam generator installed in a helium circuit for cooling t he nuclear reactor provides stable controllability of the total system , resulting in avoiding a reactor scram. A survey of control design-re lated characteristics among several hydrogen production processes reve aled the similarity of endothermic chemical reactions by the use of hi gh temperature heat and that steam is required as a reactant of the en dothermic reaction or for preheating a reactant. Based on these findin gs, a system design concept with stable controllability and universal applicability was proposed to install a steam generator as a downstrea m cooler of an endothermic reactor in the helium circuit of an HTGR-hy drogen production system.