Failure analysis of radiation monitors in NUCEF and preventive maintenance to the failure

Nakajima, Junya ; Yokosuka, Yoshiyuki; Arakawa, Yuto; Shimizu, Isamu; Umehara, Takashi

In NUCEF we monitor the radiation level continuously with 81 radiation monitors. Although these monitors are checked periodically, failures have occurred due to various reasons. Then we accumulated all monitor failures which had happened in recent 18 years, and categorized them by reason. This allowed us to find that the number of the failure much differs from monitor to monitor, and that there was a deviation between the reasons of the failure. After that, about degradation of GM tube used as dust monitor, which is by far the most of all reasons, we investigated the relation between the average cps and the interval of exchange. As a result, we couldn't find any causal relationship between the both. On the other hand, to improve the failure situation, we have exchanged expendables periodically, and furthermore, the result of the failure analysis should be fed back for better preventive maintenance.