The man who was the Ministry of Economy, Trade and Industry’s top official when the Fukushima disaster unfolded said he regretted underestimating the tsunami danger when METI was reviewing earthquake-resistance guidelines for nuclear plants before the crisis.
“We should have used our imagination,” said Kazuo Matsunaga, who was vice minister of economy, trade and industry when the meltdowns began in March last year, told a Diet-appointed panel probing the disaster Wednesday.
He was also involved in revising the guidelines as chief of the Nuclear and Industrial Safety Agency, which METI oversees, between 2004 and 2005.
NISA, the nuclear regulatory watchdog, didn’t force utilities to take tsunami countermeasures despite evidence from the devastating 2004 quake and tsunami off Sumatra, Indonesia, that “affected” a reactor-cooling pump at a nuclear power plant in India.
There was also little reference to tsunami risks in the revised quake-safety guidelines Japan compiled in 2006.
“My mind was occupied with handling the accident at Kansai Electric Power Co.’s Mihama plant,” Matsunaga said, referring to a pipe rupture in August 2004 that killed five workers and injured six.
Matsunaga was sacked last August over the handling of the Fukushima disaster, in which three reactor cores melted after tsunami from the Great East Japan Earthquake triggered a station blackout that robbed the Fukushima No. 1 plant of virtually all power, crippling its ability to cool the reactors.
Tokyo Electric Power Co. has blamed the crisis on the “unimaginable” size of the tsunami, but report after report showing Tepco was informed of the risks have cast doubt on its assertion that there was little chance of preventing the catastrophe.
For example, a study session NISA held in 2006 with several utilities, including Tepco, addressed the issue directly.
According to a document dated Aug. 2, 2006, that was made available by the utility Wednesday, NISA said at the session that five nuclear plants, including Fukushima No. 1, could experience a station blackout, or total loss of power, if their reactor buildings are hit by tsunami just 1 meter higher than the ground on which they stand.
The four other plants were Hokkaido Electric Power Co.’s Tomari plant, Tohoku Electric Power Co.’s Onagawa plant, Chubu Electric Power Co.’s Hamaoka plant and Kansai Electric Power Co.’s Oi plant — all of which have entered the media spotlight in the reactor restart debate.
But NISA did not order the utilities to prepare for such an occurrence, and simply asked Tokyo Electric to “enhance the safety” of a reactor-cooling pump.
Tepco eventually told NISA in April 2007 it would take steps to prevent the pump’s motor from being exposed to water but found it was “technically difficult” to do so, according to Tepco spokesman Junichi Matsumoto.
NISA’s request was conveyed to Ichiro Takekuro, who was then chief of the nuclear power division, and to an executive vice president of Tepco.