Preliminary safety analysis of the HTTR-IS nuclear hydrogen production system

Sato, Hiroyuki  ; Ohashi, Hirofumi ; Tazawa, Yujiro; Sakaba, Nariaki ; Tachibana, Yukio 

Japan Atomic Energy Agency is planning to demonstrate hydrogen production by thermochemical water-splitting IS process utilizing heat from the high-temperature gas-cooled reactor HTTR (HTTR-IS system). The previous study identified that the HTTR modification due to the coupling of hydrogen production plant requires an additional safety review since the scenario and quantitative values of the evaluation items would be altered from the original HTTR safety review. Hence, preliminary safety analyses are conducted by using the system analysis code. Calculation results showed that evaluation items such as a coolant pressure, temperatures of heat transfer tubes at the pressure boundary, etc., did not exceed allowable value. Also, the peak fuel temperature also did not exceed allowable value and therefore the reactor core was not damaged and cooled sufficiently.