In a preliminary report issued Wednesday, the International Atomic Energy Agency (IAEA) said Tokyo Electric Power (Tepco) had underestimated the tsunami hazard, despite warnings that a huge wave could breach the plant’s 5.7-meter protective wall.
The waves that crashed into the nuclear power complex following the March 11 magnitude-9.0 earthquake were more than 50 feet tall.
The 18-member team, led by Britain’s chief nuclear safety official Mike Weightman, backed Tepco’s claims that the damage had been inflicted by the tsunami, not the earthquake that preceded it as some reports had suggested earlier.
“In terms of the cause it is clear – the direct cause was a tsunami, associated with an earthquake, of tremendous size,” Mr. Weightman told reporters in Tokyo.
Japan’s nuclear power industry, reeling from the Fukushima accident and a loss of public and government enthusiasm for new nuclear plants, will find it difficult to ignore the IAEA’s findings. Inspectors called for the nuclear industry to take a more active role in prevention of such disasters going forward: “Nuclear plant designers and operators should appropriately evaluate and provide protection against the risks of all natural hazards.”
Unless operators can convince regulators and host communities that their facilities are safe, the country’s 54 reactors could be subject to temporary closure while safety improvements are made, severely crimping power to the country.
With only 19 reactors currently in operation in the country, experts speculate that, in a worst-case scenario, all reactors could be offline by the middle of 2012. That would deprive Japan of 30 percent of its electricity generation and result in forced power cuts over the long term.
Crucially, the inspectors called for Japan’s regulatory body to be independent of the government. The current regulator is attached to a ministry that promotes the nuclear power industry.
''[The government] needs to make sure that not only are they independent in structure, but also independent in the resources, the expertise that they have available to them,” Weightman said.
Goshi Hosono, the director of the government's nuclear crisis task force, told reporters: ''The IAEA is aware that [Japanese] regulatory authorities, including the nuclear safety agency and the Nuclear Safety Commission of Japan, were not necessarily in the best shape and the current government also has such a view. So I think reorganization is inevitable.”
The IAEA report produced few new revelations, and its criticism of tsunami defenses was tempered by praise for the emergency efforts to cool the three Fukushima reactors that suffered meltdowns in the hours after the disaster.
It said: “The response on the site by dedicated, determined and expert staff, under extremely arduous conditions has been exemplary and resulted in the best approach to securing safety given the exceptional circumstances.”
Weightman said the team, which will present its findings to the IAEA in Vienna later this month, had been granted access to nuclear sites and received the full cooperation of Tepco and nuclear safety officials.
The inspectors described the evacuation and attempts to protect the public as “impressive and extremely well organized,” adding that a “suitable and timely follow-up program on public and worker exposures, and health monitoring would be beneficial.”
“It is clear that Tepco knew about the melting of unit 1 within the first 16 hours of the earthquake at the time, but did not release that information for two months,” he told the Monitor. “This had consequences for emergency services and evacuations, yet the IAEA ignored this.
“This, and so much more, was ignored and covered up by the IAEA. We had no confidence in the IAEA fact-finding mission before, and this confirms our position.”
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