1 Sep (NucNet): A major factor that contributed to the March 2011 accident at the Fukushima-Daiichi nuclear station was the widespread assumption in Japan that its nuclear power plants were so safe that an accident of this magnitude was “simply unthinkable”, a report by the director-general of the International Atomic Energy Agency says.
The report, which is more than 200 pages long and is published with five technical volumes, says this assumption was accepted by nuclear station operators and not challenged by regulators or by the government. “As a result, Japan was not sufficiently prepared for a severe nuclear accident in March 2011,” the report says.
IAEA director-general Yukiya Amano said in his foreword to the report that the accident, the worst emergency at a nuclear power plant since the Chernobyl disaster in 1986, exposed “certain weaknesses” in Japan’s regulatory framework. Responsibilities were divided among a number of bodies, and it was not always clear where authority lay.
Mr Amano said there were also certain weaknesses in plant design, in emergency preparedness and response arrangements and in planning for the management of a severe accident.
“There was an assumption that there would never be a loss of all electrical power at a nuclear power plant for more than a short period,” he said. “The possibility of several reactors at the same facility suffering a crisis at the same time was not considered. And insufficient provision was made for the possibility of a nuclear accident occurring at the same time as a major natural disaster.”.
Mr Amano said since the accident, Japan has reformed its regulatory system to better meet international standards. It gave regulators clearer responsibilities and greater authority. The new regulatory framework will be reviewed by international experts through an IAEA Integrated Regulatory Review Service mission. Emergency preparedness and response arrangements have also been strengthened.
The IAEA said the report assesses the causes and consequences of the accident, which was triggered by a tsunami that followed a massive earthquake. It considers human, organisational and technical factors and aims to provide an understanding of what happened, and why, so that lessons learned can be acted upon by governments, regulators and nuclear power plant operators.
The report considers the accident itself, emergency preparedness and response, radiological consequences of the accident, post-accident recovery and the activities of the IAEA since the accident. It examines measures taken, both in Japan and internationally.
“Although nuclear safety remains the responsibility of each individual country, nuclear accidents can transcend national borders,” Mr Amano said. “The Fukushima-Daiichi accident underlined the vital importance of effective international cooperation.”
Mr Amano had announced in 2012 that the IAEA would prepare an assessment of the accident, addressing both its causes and consequences. The IAEA said the report is the result of an extensive collaboration that involved some 180 experts from 42 IAEA member states and several international bodies.
The report is online: http://bit.ly/1hQl49S
