Dynamic behavior of the cryogenic hydrogen system using only a heater control

Tatsumoto, Hideki; Aso, Tomokazu ; Otsu, Kiichi; Uehara, Toshiaki; Sakurayama, Hisashi; Kawakami, Yoshihiko; Futakawa, Masatoshi  

A pressure control system, which consists of a heater for the thermal compensation and a cryogenic accumulator with a bellows acting as a volume controller, is prepared to mitigate a pressure fluctuation caused by the sudden heat load of kW-order. A stable operation of the cryogenic hydrogen system has been conducted since May 2008. However, a major cryogenic accumulator failure was encountered during a short maintenance period, in February 2010. In order to resume the 120-kW proton beam operation as soon as possible, we studied the temporary operational approach without using the cryogenic accumulator because the heat load was relatively low and improved a part of the hydrogen loop temporarily. It was confirmed through an on-beam commissioning that the pressure rise could be mitigated below the allowable value of 100 kPa using only the heater control. The 120-kW proton beam operation was successfully resumed two months later.