Trouble again at Monju reactor

August 3, 2016

Repeated problems at Monju reactor

http://www3.nhk.or.jp/nhkworld/en/news/20160803_32/

Another maintenance irregularity has come to light at the currently-idle Monju experimental reactor in Fukui Prefecture, central Japan. Japan's Nuclear Regulation Authority learned on Wednesday that workers at the prototype fast breeder reactor failed to follow a manual for 6 months after an alarm went off at the pool for spent nuclear fuel.

The alarm last November indicated that water inside the pool had become dirty.

The procedural manual says if the alarm goes off, workers must replace ion exchange resins inside the water purification system. But the resins weren't there in the first place, and workers didn't install them until May this year.

The regulatory authority judged it as a violation of safety provisions.

It recommended last November that the reactor's operator be replaced. It said the operator, the Japan Atomic Energy Agency, was unfit for the job after as many as 10,000 safety oversights were revealed at the reactor.

Authority members pointed out the latest report underscores the lack of alertness among workers, as the alarm went off immediately after the recommendation. They called the repeated safety violations a serious problem.

Authority Chairman Shunichi Tanaka said it's deplorable that a culture of safety is fundamentally lacking at Monju.

The Japan Atomic Energy Agency refuted claims that workers did nothing for 6 months. Officials said that they didn't consider the alarm to be urgent as water quality sensors were at a higher sensitivity than the standard.

The agency added that it took what it thought were necessary measures, having removed dirt from the surface of the water to improve the water quality and increasing monitoring.