Editorials

End of the line for Tsuruga reactor

The Nuclear Regulation Authority on May 22 accepted its five-member expert panel’s report that the D-1 fracture zone of pebbles and sediment running beneath the No. 2 reactor at Japan Atomic Power Co.’s Tsuruga nuclear power plant in Fukui Prefecture is an active fault.

JAPC has long contended that the zone is not an active fault. But given the NRA’s position, it will likely have no other choice but to give up on restarting the reactor and to decommission it.

The NRA has not only refuted the company’s contention but also demonstrated that the safety check done by the now-defunct Nuclear and Industrial Safety Agency of the trade and industry ministry was shoddy. The NRA’s conclusion has shown that it will give priority to nuclear power plant safety over profitability and will not approve nuclear power plant operations if there is even the slightest chance of danger.

The NRA faithfully followed the lesson from the Fukushima nuclear catastrophe: that even the smallest possibility of an accident must be eliminated. It should maintain this position even in the face of pressure from the government and the power industry. The power industry should learn from the Fukushima disaster and not ignore any potential dangers however small.

NRA Chairman Shunichi Tanaka said his organization will not carry out a safety review of the reactor in question for licensing because safety standards ban the construction of important nuclear-related facilities above an active fault.

Although JAPC is strongly opposing the NRA’s conclusion, it should be remembered that both it and the Nuclear and Industrial Safety Agency in the past failed to recognize the danger from the Urazoko fault, an active fault lying 200 to 300 meters from the Nos. 1 and 2 reactors of the Tsuruga plant.

The NRA concluded that the D-1 fracture zone running beneath the No. 2 reactor should be considered an active fault because it cannot be proven that the zone has not moved in the past 130,000 years and pointed to the possibility that it will move with the Urazoko fault, thus affecting facilities constructed above the zone.

The NRA panel is now carrying out geological studies at six nuclear power plants. The government should allocate enough funds and personnel to ensure the NRA can rapidly yet thoroughly carry out its studies. The government also should work out necessary measures to help accelerate the decommissioning of the No. 2 reactor, including securing a storage site for its radioactive waste. Similar preparations may be needed for other reactors facing the same fate.

Even though the Tsuruga reactor contains no nuclear fuel, 1,705 fuel assemblies are stored onsite in a fuel pool. If the pool is damaged by a quake, the fuel assemblies could rupture and emit radioactive substances. This shows that even a nuclear power plant kept offline can pose dangers, and is all the more reason why the government should adopt a policy to end Japan’s reliance on nuclear power generation as soon as possible.