A team of experts from the Nuclear Regulation Authority on Wednesday began a two-day inspection of faults beneath the Monju fast-breeder nuclear reactor in Tsuruga, Fukui Prefecture.
The team will assess whether the eight crush zones are active faults. Under Japanese law, reactors are not permitted to be built above active faultlines.
The Monju reactor’s future has been in limbo for some time. In late May, the Nuclear Regulation Authority ordered the Japan Atomic Energy Agency not to restart the reactor and instructed the company to improve its safety measures. The trouble-plagued next-generation test reactor has been cited for numerous safety violations.
Monju uses plutonium fuel instead of conventional uranium and produces radioactive substances that can be reused as fuel. After nearly 50 years in the works, the reactor is still struggling to get online.
The previous government tried to terminate Monju under its nuclear phase-out plan, but Prime Minister Shinzo Abe’s government quickly reversed course as it pushed to restart commercial reactors that have been idle since a March 2011 earthquake and tsunami triggered a nuclear disaster at the Fukushima Daiichi plant.
Nuclear Regulation Authority chairman Shunichi Tanaka has said that Monju’s operator lacked a “safety culture” and deserved severe action.
Japan built Monju as a “dream reactor” to fulfill its energy needs, with the reactor meant to be a centerpiece of a self-sustainable fuel cycle. To complete the cycle, Japan has been building the Rokkasho fuel recycling plant in northern Japan to extract uranium and plutonium from spent fuel and fabricate hybrid fuel made from the two radioactive elements.
But with both Monju and Rokkasho having technical problems, Japan has built up a large stockpile of plutonium extracted overseas and at home, causing international proliferation concerns.
Monju successfully generated power using MOX — mixed oxide fuel, a mix of uranium and plutonium — in 1995, but months later, a massive leakage of cooling sodium caused a fire. Monju had another test run in 2010 but stopped again after a fuel exchanger fell into the reactor vessel.
Wednesday’s inspection by the Nuclear Regulation Authority is the fourth at a nuclear power plant in Japan this summer.
Only two of Japan’s 50 reactors are currently online, but four utilities—-Kyushu Electric Power Co, Hokkaido Electric Power Co, Shikoku Electric Power Co and Kansai Electric Power Co—have applied to restart 10, subject to approval by the Authority.