Tokyo Electric Power Co. (TEPCO) has revealed that it had explained that the seismic capacity of a quake-absorbing structure called an "important anti-seismic building" at its Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture was higher than it actually was, now saying that it "cannot withstand all types of shaking."
TEPCO made the revelation at a Nuclear Regulation Authority (NRA) safety screening session on the plant's No. 6 and 7 reactors on Feb. 14. The "important anti-seismic building" is supposed to serve as a frontline base in the event of a nuclear accident. The NRA demanded TEPCO give detailed explanations about how and why it provided the wrong information, saying harshly, "We cannot overlook this."
According to the NRA and other sources, of the so-called "standard earthquake vibrations," the strongest seismic shaking the important anti-seismic building is assumed to withstand, TEPCO had said that the structure would not be able to withstand some types of seismic shaking. But the utility reversed its previous explanations at the latest meeting, saying, "It cannot withstand all types of shaking." TEPCO said that it had given the wrong explanation because the facts had not been conveyed from its section that analyzed the seismic capacity of the building in 2014 to the division in charge of attending safety screening session meetings.
A TEPCO official apologized at the meeting, saying, "We are sorry that our information sharing was insufficient."