Government inspectors conducted on-the-spot examinations Saturday of the inspection records of 11 reactors at five nuclear plants of three utilities embroiled in damage coverup scandals, the government said.
The Nuclear and Industrial Safety Agency inspectors carried out the investigations of the records submitted by Tokyo Electric Power Co., Chubu Electric Power Co. and Tohoku Electric Power Co., it said. The agency is part of the Ministry of Economy, Trade and Industry.
The five nuclear plants subject to the probe are located in Fukushima and Miyagi prefectures, Shizuoka Prefecture, and Niigata Prefecture.
The inspectors seek to clarify the exact nature of the coverups, which were perpetrated in efforts to conceal the discovery of cracks in pipes that carry primary cooling water in boiling-water reactors, agency officials said.
The inspectors wish to learn what prompted the power utilities to hide reactor-related problems, they said.
Government inspectors rarely conduct simultaneous on-the-spot investigations of nuclear plants at different power utilities.
The agency said it has divided its inspectors into five teams of three to six examiners, with each team assigned to one of the five plants.
The teams are examining the inspection records of reactors at the plants and will question power company officials at each plant concerning the reported coverups, it said.
The three utilities earlier acknowledged that they failed to report to the government that cracks had been detected at the reactors, though they had discovered the faults during past regular checks.
Tepco said Friday it detected cracks in eight of its nuclear reactors at the Fukushima No. 1 and 2 nuclear power plants, as well as the Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture. From two to 12 cracks were found at each of the eight reactors.
Chubu Electric Power said Friday it detected nine instances of cracks in two reactors at the Hamaoka nuclear plant in Shizuoka Prefecture.
Also on Friday, Tohoku Electric Power acknowledged finding cracks in four pipes in one nuclear reactor at the Onagawa nuclear plant in Miyagi Prefecture.
Cracks in coolant pipes are potentially more dangerous than cracks in reactor shrouds, which were the subject of the initially revealed coverups. In the earlier cases, Tepco acknowledged having falsified reports.
Tohoku Electric Power supplies power in the Tohoku region. Chubu Electric Power serves Aichi, Nagano, Yamanashi and other prefectures.
“We will deal with this problem in a stern manner,” Takeo Hiranuma, minister of economy, trade and industry, said Friday.
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