TOKYO — The nuclear accident at Fukushima was a preventable disaster rooted in government-industry collusion and the worst conformist conventions of Japanese culture, a parliamentary inquiry concluded Thursday.
The report, released by the Fukushima Nuclear Accident Independent Investigation Commission, also warned that the plant may have been damaged by the earthquake March 11, 2011, even before the tsunami struck — a worrying assertion as the quake-prone country starts to bring its reactor fleet back online.
The commission challenged some of the primary story lines that the government and the operator of the Fukushima Daiichi Nuclear Power Plant have used to explain what went wrong in the early days of the crisis.
Despite assigning widespread blame, the report also avoids calling for censure of specific executives or officials. Some citizens’ groups have demanded that executives of the Tokyo Electric Power Co. face charges of criminal negligence — a step that Kiyoshi Kurokawa, the panel’s chairman, said Thursday was out of its purview. Criminal prosecution ‘‘is a matter for others to pursue,’’ Kurokawa said at a news conference after the report’s release.
“It was a profoundly manmade disaster that could and should have been foreseen and prevented. And its effects could have been mitigated by a more effective human response,’’ said Kurokawa, a medical doctor and an academic fellow at the National Graduate Institute for Policy Studies, in the report’s introduction.
The 641-page report criticized plant operator Tokyo Electric for being too quick to dismiss earthquake damage as a cause of the fuel meltdowns at three of the plant’s six reactors, which overheated when the site lost power. Tokyo Electric has said that the plant withstood the earthquake that rocked eastern Japan, instead blaming the disaster on what some experts have called a ‘‘once-in-a-millennium’’ tsunami that ensued. Such a rare calamity was beyond the scope of contingency planning, Tokyo Electric executives have suggested, and was unlikely to pose a threat to Japan’s other nuclear reactors in the foreseeable future.
But by suggesting that the plant may have sustained extensive damage from the earthquake — a far more frequent occurrence in Japan — the report in effect casts doubts on the safety of all of Japan’s nuclear plants. The report came just as a nuclear reactor in western Japan came back online Thursday, the first to restart since the Fukushima crisis.
The parliamentary report, based on more than 900 hours of hearings and interviews with 1,167 people, suggests that reactor No. 1, in particular, may have had earthquake damage — including the possibility that pipes burst in the shaking, leading to a loss of cooling even before the tsunami struck the plant about 30 minutes after the initial earthquake.
The report emphasized that a full assessment would be needed to review the inner workings of the reactors, which could take years.
‘‘However, it is impossible to limit the direct cause of the accident to the tsunami without substantive evidence. The commission believes that this is an attempt to avoid responsibility by putting all the blame on the unexpected [the tsunami],’’ the report said, ‘‘and not on the more foreseeable quake.’’
The commission charged that the government, Tokyo Electric, and nuclear regulators failed to implement basic safety measures despite being aware of risks posed by earthquakes, tsunamis, and other events that might disable power systems and put nuclear plants at risk. Even though the government-appointed Nuclear Safety Commission revised earthquake resistance standards in 2006 and ordered nuclear operators across the country to inspect their reactors, for example, Tokyo Electric did not carry out any checks, and regulators did not follow up, the report said.
The report blamed the tepid response on collusion between the company, the government, and regulators — all of which had ‘‘betrayed the nation’s right to safety from nuclear accidents.’’ Tokyo Electric ‘‘manipulated its cozy relationship with regulators to take the teeth out of regulations,’’ the report said. ‘‘There were many opportunities for taking preventive measures before March 11. The accident occurred because Tokyo Electric did not take these measures.’’
Regulators went along, said the report, which reserved its most condemning language for criticism of a culture in Japan that suppresses dissent and outside opinion, which might have prompted changes to the country’s lax nuclear controls.