The International Atomic Energy Agency has concluded that confusion over responsibility was a factor behind the inadequate response to the accident at the Fukushima No. 1 nuclear power plant.
The International Atomic Energy Agency has concluded that confusion over responsibility was a factor behind the inadequate response to the accident at the Fukushima No. 1 nuclear power plant.
The agency's summary report was released on June 1 and will be taken up at a ministerial-level meeting of the IAEA scheduled for June 20-24 in Vienna.
The IAEA team of experts arrived in Japan on May 24 and is expected to depart on June 2.
To gain lessons for nuclear power plants around the world, the team visited not only the Fukushima No. 1 plant, but also the Fukushima No. 2 nuclear power plant and the Tokai No. 2 nuclear power plant that were also damaged by the March 11 Great East Japan Earthquake and tsunami.
The IAEA investigators also interviewed officials at Tokyo Electric Power Co., the operator of the Fukushima plants, as well as the Ministry of Economy, Trade and Industry.
The report states that the direct cause of the accident at the Fukushima No. 1 plant was the quake and tsunami, which led to the loss of electric power sources and many functions necessary to cool the reactor cores at the plant.
While TEPCO reviewed the height of tsunami expected to hit the Fukushima plant after 2002, the IAEA report states that the tsunami hazard was "underestimated" in several parts.
Although measures were in place to deal with a serious accident, the report said those measures were inadequate to handle simultaneous accidents at a number of reactors.
Among the lessons to be learned, according to the IAEA report, is the need for measures to prevent flooding at nuclear reactors as well as the installation of an early-warning system for tsunami.
The report also called for securing an adequate number of personnel and equipment to be able to respond to a disaster striking simultaneously at a number of different reactors at a number of different locations.
Although the report described the initial response after the quake and tsunami as the best that could have been done under such extreme circumstances, it also pointed out that the complicated organizational structure in Japan may have led to delays in making important decisions during the emergency.
In addition, the report cited a lack of a joint understanding among those in related government agencies as well as at TEPCO.
The report describes the impression obtained through interviews by IAEA experts of different views on where responsibility lay in dealing with the crisis.
The report states that while some people said the government was directly responsible, others said it lay with the electric power company based on the principles for safety during an emergency.
The report added that the head of a nuclear power plant did in fact act recognizing the responsibility of the position he held.