LEAD: Inquiry rakes nuke plant operator, Japan government over coals

Dec 26, 2011, 12:37 GMT

Tokyo - An investigation released Monday into the world's worst nuclear accident since Chernobyl blasted the Japanese power plant's operator and its government for mistakes made before and after the March incident.

The inquiry found that the Tokyo Electric Power Co (TEPCO) and the government's nuclear regulator were so unprepared for a disaster the size of the March 11 magnitude-9 earthquake and tsunami and what it might do to nuclear reactors that proper response mechanisms weren't in place and what planning had been done wasn't always implemented, news reports said.

The 507-page preliminary report into the accident at the Fukushima Daiichi Nuclear Power Station also criticized TEPCO for saying it could not prepare for the unimaginable, saying it was responsible for planning for such an unexpected disaster, given its disastrous consequences.

The emergency response was also hampered by poor communications and coordination, it said.

The 10-metre waves of the tsunami swamped the coastal plant 250 kilometres north-east of Tokyo, shutting off its cooling systems. The nuclear reactors overheated, leading to meltdowns, explosions and fires and releasing radioactive materials into the environment. Residents living within 20 kilometres from the plant were evacuated and have yet to return home.

TEPCO 'had not expected a situation in which all power sources would be lost at multiple reactors simultaneously due to an extremely severe natural disaster, and it had not provided enough training and education to respond to this situation,' the report said.

Workers mistakenly believed a cooling system was functioning in the first of the plant's six nuclear reactors, causing a delay in the dispatch of fire trucks that eventually sprayed and cooled down the reactor, it said.

In reactor number three, workers stopped an emergency cooling system without reporting it, the investigation found.

If both problems had not occurred, the damage to the reactors could have been lessened and a smaller amount of radioactivity would likely have been released, the report said.

The government's nuclear power regulator, the Nuclear Industrial and Safety Agency, left the plant after the disaster and, when ordered to return, provided little help to TEPCO, according to the inquiry, which was based on 900 hours of interviews with 456 people involved in the accident.

TEPCO was slow in relaying information about the accident to the government, the government performed poorly in gathering information and the industry ministry did not send personnel to TEPCO's headquarters to improve the situation, said the investigation committee, headed by engineering professor Yotaro Hatamura.

Some residents were evacuated into areas hit by the fallout, it said.