Although a manual existed that outlined the criteria for a meltdown, Tokyo Electric Power Co. admitted that only five or so employees at its main office knew of it at the onset of the 2011 nuclear crisis.
Those employees belonged to a section that manages the manual at the company’s Tokyo headquarters, TEPCO said at a news conference on May 30.
The utility has been under fire for the delay in acknowledging in May 2011 that triple meltdowns took place at the Fukushima No. 1 nuclear power plant, two months after they actually occurred following the Great East Japan Earthquake and tsunami.
TEPCO had maintained that the reactors at the plant suffered “core damage,” rather than more serious meltdowns.
Explaining the delay, the company initially cited a lack of guidelines for determining a meltdown.
But TEPCO admitted in February this year that the company manual did contain entries defining a meltdown, although the company said it was unaware of the descriptions for the past five years. The criteria requires the company to declare a meltdown when damage to a reactor core passes 5 percent.
Takafumi Anegawa, chief nuclear officer with TEPCO, told the news conference that a third-party panel will investigate why it took the company five years to disclose the existence of the manual.
In April, a TEPCO senior official admitted that he knew of the criteria when the crisis was unfolding at the plant.