The No. 3 reactor at the Fukushima No. 1 Nuclear Power Plant is seen from a Mainichi Shimbun helicopter on Nov. 21, 2017
Tokyo Electric Power Co. (TEPCO), operator of the disaster-stricken Fukushima No. 1 Nuclear Power Plant, refused in 2002 to calculate the potential effects of tsunami in case of an earthquake off Fukushima Prefecture when a now-defunct nuclear watchdog told the utility to conduct an evaluation, the Mainichi Shimbun has learned.
A former safety screening division official of the Ministry of Economy, Trade and Industry’s Nuclear and Industrial Safety Agency (NISA) told the Mainichi Shimbun on Jan. 29 that TEPCO did not accept the agency’s request even though the latter tried to convince the utility after the government released a long-term assessment report that a major earthquake could hit off the Pacific coast including areas off Fukushima Prefecture, possibly triggering massive tsunami. This is the first time that exchanges between the then nuclear agency and TEPCO following the release of the government report have come to light.
In July 2002, the government’s Headquarters for Earthquake Research Promotion released the long-term assessment report saying that an earthquake similar to the 1896 Sanriku Earthquake could hit off the Pacific from the northern Sanriku to Boso areas. The official held a hearing on TEPCO the following month as to whether the report would affect safety measures at the Fukushima No. 1 plant.
According to the official as well as the statement submitted by the government to the trial of a lawsuit filed by Fukushima nuclear evacuees against TEPCO and the state, NISA told the utility to calculate a possible earthquake-tsunami disaster off the coast from Fukushima to Ibaraki prefectures, pointing out that Tohoku Electric Power Co. had been considering conducting an assessment on areas quite far south. In response, TEPCO representatives showed reluctance, saying that the calculation would “take time and cost money” and that there was no reliable scientific basis in the assessment report. The TEPCO officials reportedly resisted for about 40 minutes on the matter. In the end, the agency accepted the utility’s decision to shelve the earthquake-tsunami estimate.
In 2006, NISA again requested TEPCO to prepare its nuclear plants for massive tsunami exceeding envisioned levels, but the company did not comply, before finally conducting a calculation in 2008. The utility concluded that waves up to a height of 15.7 meters could hit the Fukushima plant, but did not take measures according to the estimate.
The former nuclear agency official said as someone involved in the screening of earthquake resistant measures it was very unfortunate that the accident at the Fukushima plant occurred, but stopped short of commenting on the legitimacy of the agency’s handling of the matter, saying, “I can’t put it in words casually.”
The attorney representing Fukushima nuclear evacuees in the redress suit commented that the finding exposes the maliciousness of TEPCO, while also pointing to the responsibility of the central government. A TEPCO public relations official, meanwhile, said that the company would not comment on the matter because the trial was ongoing.