Demonstration of Nuclear Hydrogen Production Utilizing the Japan’s HTTR: Control Scheme Evaluation of the HTTR-IS Nuclear Hydrogen Production System

One of the key technology requirements to achieve the nuclear hydrogen demonstration is the establishment of control scheme which harmonizes the reactor operation with chemical plant operation. This study focused on developing the control scheme to be considered in the HTTR-IS nuclear hydrogen production system, which are in case of (a) abnormal shut-down and (b) restart-up of the IS process. The key parameters and equipments have been determined and the control operations are simulated. The simulation results show that the impact of abnormal events initiated in the IS process on the reactor operation can be effectively minimized by the rapid initiation of diverter valves using model-based fault diagnosis method. Furthermore, the thermal shock to components in the IS process can be prevented in case of restart-up operation of the IS process by controlling the helium gas flow-rate of primary and secondary cooling system. It is confirmed by the analysis that the control scheme developed enable to maintain the reactor operation normally under all conditions and supply heat from nuclear reactor to the IS process hydrogen production system flexibly.