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Panel to probe why Fukushima meltdown criteria manual wasn't found for almost 5 years

A third-party investigative panel to be set up by Tokyo Electric Power Co. (TEPCO) will focus on why the company failed to find its own manual containing criteria for judging nuclear reactor core meltdowns until nearly five years after the onset of the Fukushima nuclear disaster, and whether the document was covered up.

    The discovery of the manual, which came earlier this month, highlights the lack of a crisis mentality among TEPCO employees, as well as the utility's fear of a negative reaction from the government, which was excessively nervous about the phrase, "reactor core meltdowns."

    Akio Takahashi, president of the Japan Atomic Industrial Forum, Inc. (JAIF), who was in charge of responding to the March 2011 Fukushima No. 1 Nuclear Power Plant accident as a then TEPCO fellow, declined to mention the manual issue.

    "I don't know whether there was a judgment that meltdowns had occurred," he told a JAIF regular news conference on Feb. 25. This is despite the fact that there are records that TEPCO employees held teleconference discussions on the company's response to the accident on the assumption that meltdowns had occurred.

    The manual on countermeasures against nuclear disasters, which was compiled in 2003, defines a meltdown as a situation in which over 5 percent of the core of a reactor has been damaged. Based on the manual, TEPCO could have determined three days after the onset of the disaster triggered by the March 11, 2011 quake and tsunami that meltdowns had indeed occurred at the Fukushima No. 1 complex. Yet it was more than two months after the disaster broke out that the company acknowledged the meltdowns.

    Questions remain as to whether the existence of the manual had been covered up. Tsuneo Futami, a specially appointed professor at the Tokyo Institute of Technology who served as head of the Fukushima No. 1 plant from 1997 to 2000, said, "I guess employees failed to share the manual because they were under the impression that meltdowns would never take place, and forgot its existence."

    Some employees, however, should have been involved in compiling the manual.

    One of the possible reasons the manual's existence was not disclosed is that TEPCO was wary of how the government would react.

    At a news conference on March 12, 2011, following a hydrogen explosion at the power station's No. 1 reactor building, a then deputy director-general at the Nuclear and Industrial Safety Agency (NISA), who was serving as a spokesman for the now-defunct agency, clearly stated that a meltdown had occurred at the plant.

    Fearing that the word, "meltdown," could give the public the impression that the nuclear plant had been disastrously damaged, however, the prime minister's office admonished NISA and its spokesman was replaced. From then on, TEPCO avoided using the term "meltdown," and instead used softer words, such as "damage."

    The possibility cannot be ruled out that TEPCO failed to check the plant's status against the manual, worrying about how the prime minister's office would react.

    TEPCO's report on its investigation into the disaster, released in 2012, makes no mention of the manual, suggesting that its in-house probe was shoddy. If the third-party panel to be set up shortly is to end up releasing a report that is favorable to TEPCO, the utility would come under fire from the public. The emergence of the manual's existence has put TEPCO in a corner as it aims to restart its idled Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture.

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