Safety evaluation of the HTTR-IS nuclear hydrogen production system

HTTR-IS水素製造システムの安全評価

佐藤 博之  ; 大橋 弘史 ; 田澤 勇次郎; 坂場 成昭 ; 橘 幸男 

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

高温ガス炉を熱源とした水素製造システムの安全評価手法確立を目的として、HTTRを熱源としてISプロセスによる水素製造を行うHTTR-ISシステムの安全解析評価を行った。摘出された5つの運転時の異常な過渡変化及び3つの事故事象に対してプラント過渡挙動評価を行った結果、評価項目である燃料最高温度,原子炉冷却材圧力バウンダリ温度及び圧力は評価基準を上回ることがないことを明らかにした。

In the present study, a practical safety evaluation method, which enables to design, construct and operate hydrogen production plants under conventional chemical plant standards, is proposed. An event identification for the HTTR-IS nuclear hydrogen production system is conducted in order to select abnormal events which would change the scenario and quantitative results of the evaluation items from the existing HTTR safety evaluation. In addition, a safety analysis is performed for the identified events. The results of safety analysis for the indentified five AOOs and three ACDs show that evaluation items such as a primary cooling system pressure, temperatures of heat transfer tubes at pressure boundary, etc., do not exceed the acceptance criteria during the scenario. In addition, the increase of peak fuel temperature is small in the most severe case, and therefore the reactor core was not damaged and cooled sufficiently.