HTTR水素製造システムの高温隔離弁の開発

Development of high temperature isolation valve for the HTTR hydrogen production system

西原 哲夫 ; 榊 明裕*; 稲垣 嘉之; 高見 和男*

Nishihara, Tetsuo; Sakaki, Akihiro*; Inagaki, Yoshiyuki; Takami, Kazuo*

原研ではHTTR水素製造システムの研究開発を進めている。本システムの主要な機器の1つに、原子炉格納容器を貫通する高温ヘリウム配管に設置する高温隔離弁がある。高温隔離弁はアングル弁を採用し、基本構造の検討を行うとともに、応力解析を行い、構造健全性を確認した。また、許容漏えい率を定め、それを満足するための弁座構造及び締切荷重を決めるための小型要素モデルを用いたヘリウム漏えい試験を行った。くさび型の弁座は締切回数の増加とともに漏えい量が増加したが、平面型の弁座は締切回数によらず漏えい量はほぼ一定であり、許容値を十分満足するものであった。この結果から、高温隔離弁の弁座は平面型を採用し、締切荷重は30MPaに設定した。

JAERI has been carried out research and development on the HTTR hydrogen production system. One of the key components in this system is a high temperature isolation valve (HTIV) installed on the hot helium gas piping penetrating the reactor containment vessel. Angle valve with inner thermal insulator was selected for HTIV and conceptual design was performed. The structural integrity of HTIV was clarified by the stress analyses. Allowable helium leak rate of HTIV was discussed. Helium leak tests using small-scaled valve seat models were performed to decide the seat surface shape and valve closing force. The test results show that the leak rate of wedge shape seat increased in proportion to the number of simulated temperature and stress cycles loaded on the seat models before helium leak test, however that of flat seat did not depend on the number of cycles. So flat seat is adopted for HTIV. It was found that the seat closing force of 30 MPa is reasonable to meet the allowable helium leak rate.