Current status of JRR-3, 2; Maintenance in long-term shutdown period and work for re-operation

JRR-3の現状,2; 長期停止期間中の保守及び再稼働に向けた業務

上石 瑛伍; 和田 茂; 村山 洋二

Kamiishi, Eigo; Wada, Shigeru; Murayama, Yoji

JRR-3 has been in shutdown for approximately five years after the last reactor operation. The so long-term reactor shutdown period is our first experience after first criticality. During the shutdown period, main facilities such as cooling system and safety protection system have been kept the integrity by checking operation regularly once in a month. In addition to the hardware side, we feel the importance of keeping and training skills of operators. Therefore, we carried out training using reactor simulator and operation of the most of reactor facilities (the cooling system, instrumentation and control system, etc.) for 10 days a year. In response to the accident at Fukushima Daiichi NPS, the Reactor Regulation Act was revised in June 2012, for the purpose of introducing new regulations based on lessons learned from the accident and the latest technical analysis. The Act stipulates the application of "back-fit system" that is a system for adopting the latest technological findings and obligating approved nuclear facilities to conform to the new requirements. We have conducted the necessary checks and reassessments of JRR-3, and completed the preparations for the relevant applications. We then submitted the application document to change the current reactor license to the Nuclear Regulation Authority (NRA) for their review to verify conformity to new regulatory requirements on September 26, 2014.