Kansai Electric Power Co. manually shut down the No. 1 reactor at its Oi nuclear power plant in Oicho, Fukui Prefecture, on Saturday (July 16) to investigate what caused the pressure to drop inside a tank in the reactor’s emergency cooling system.

The Oi nuclear plant is a major source of power, with an output capacity of nearly 1.2 million kilowatts. Kansai Electric, which depends on nuclear power for about 50 percent of its output, has lost a precious possession.

Kansai Electric has 11 nuclear reactors, all in Fukui Prefecture, and the shutdown of the Oi power plant’s No. 1 reactor brought its number of suspended reactors to five. Another two are scheduled to be shut down this week for regular scheduled inspections.

This may make it even more difficult to maintain a stable power supply in the Kansai region as midsummer approaches.

A faulty valve in the tank is suspected of causing the trouble at the Oi power plant. As the pressure returned to normal quickly, there was no leak of radioactive substances. The problem is not expected to directly lead to a serious accident.

The concern now is that it is unclear when the No. 1 reactor will be reactivated. Even if the cause of the trouble is identified and preventive measures taken, it will be difficult to restart operations for the time being.

This is because Prime Minister Naoto Kan caused confusion by making stress tests a condition for reactivating reactors that are suspended for regular inspections.

The Oi power plant’s No. 1 reactor was reactivated for fine-tuning in the final stage of its regular inspections on March 10, the day before the Great East Japan Earthquake.

Normally, an application for the final inspection would have been filed about a month after a reactor is reactivated and commercial operations could begin. However, the No. 1 reactor has now been operating at full capacity for more than four months.

The deadline for applying for the final inspection is not stipulated in law. The Nuclear and Industrial Safety Agency and local governments tacitly approved Kansai Electric’s continuing operations as a special measure to deal with power shortages.

Following the series of accidents at the Fukushima No. 1 nuclear power plant, Kansai Electric has already implemented, at the urgent instruction of the nuclear safety agency, measures to guard against tsunami and strengthen emergency power supply systems.

With suspended reactors now required to pass stress tests before they can be reactivated, the Fukui prefectural government may take a tough line toward the restart of the Oi power plant’s No. 1 reactor and others in the prefecture.

The confusion caused by the Kan administration also is affecting the Monju prototype fast-breeder reactor in Tsuruga in the prefecture.

After Kan declared that he wanted Japan to be free from its reliance on nuclear power plants, education, culture, sports, science and technology minister Yoshiaki Takaki made a remark last week that can be taken to mean the government will consider suspending the development of the Monju reactor.

He retracted the remark soon after.

A large amount of money has been spent on the Monju reactor as an essential part of Japan’s nuclear power policy. The Fukui prefectural and Tsuruga city governments are perplexed by such abrupt remarks, which were not based on discussions within the government.

Politicians should not confuse local governments that host nuclear power plants as a result of their own haphazard and irresponsible responses to nuclear power issues.

Editorial, The Yomiuri Shimbun

(Asia News Network)