The Nuclear and Industrial Safety Agency is letting Tokyo Electric Power Co. reactivate one of the seven nuclear reactors at its huge plant in Niigata Prefecture, which was shut down by a devastating earthquake in July 2007, government sources said Saturday.
The No. 7 reactor at the Kashiwazaki-Kariwa nuclear power plant run by Tepco may be able to restart commercial power generation by summer, when demand typically peaks. But first the local authorities from the city of Kashiwazaki and the village of Kariwa will have to give the green light, Tepco said.
According to Tepco's plan, the reactor will undergo a trial run before going into commercial operation. Its output will be raised in phases to full capacity, and if any glitches develop the reactor will be shut down again. The record for the trial will be submitted to the government for appraisal.
The agency endorsed Tepco's plan on the grounds that its safety precautions are sufficient, but some experts are disputing that view and saying that the reactor is not strong enough to withstand another major earthquake because Tepco has underestimated the physical impact that another quake could have if one struck the facility again.
All seven reactors at Kashiwazaki-Kariwa, which is situated on the coast of the Sea of Japan, were damaged by the 2007 quake, which caused a fire and caused radioactive water to leak into the sea.
The government later concluded that the earthquake's intensity exceeded the design parameters of the facility and the architects' expectations.
To date, Tepco has spent about ¥30 billion to reinforce the quake resistance of the No. 6 and 7 reactors. But the remaining five are still undergoing inspection.