Pipes were worn thinner than government standards in thermal reactors operated by four of the nation's nine electric power companies, according to the results of their internal inspections released Tuesday.
The pipes were below regulation thinness in 23 places at nine reactors at seven thermal power plants, they said.
The utilities conducted the inspections in line with instructions from the Nuclear and Industrial Safety Agency following a fatal Aug. 9 accident at Kansai Electric Power Co.'s Mihama Nuclear Power Plant.