Differential pressure rise event for filters of HTTR primary helium gas circulators, 2; Investigation of filter deposits and recurrence prevention measures

Nemoto, Takahiro; Fujiwara, Yusuke ; Arakawa, Ryoki ; Choyama, Yuya; Nagasumi, Satoru; Hasegawa, Toshinari  ; Yokoyama, Keisuke ; Watanabe, Masashi  ; Onishi, Takashi  ; Kawamoto, Taiki; Furusawa, Takayuki ; Inoi, Hiroyuki; Nojiri, Naoki ; Iigaki, Kazuhiko ; Saito, Kenji ; Hori, Naohiko 

In order to investigate the cause of the increase in differential pressure in the primary helium circulator filter that occurred during the RS-14 cycle, a clogged filter was investigated. As a result of the investigation, deposits caused by silicone oil were confirmed on the surface of the filter element. These results revealed that the cause of filter clogging was silicone oil mixed into the primary system due to performance deterioration of the charcoal filter in the gas circulator of primary helium purification system. As a measure to prevent the recurrence of this event, in addition to the conventional management based on operating hours for replacing of charcoal filter in the gas circulator of primary helium purification system, we have established a new replacement plan for every three years.