Gov’t nuclear commission failed to expand antidisaster zone in 2006

The government's Nuclear Safety Commission did not expand the so-called emergency planning zone in its guidelines for possible nuclear disasters when its subcommittee considered the matter in 2006, leaving it smaller than the area for emergency measures in the current nuclear crisis, minutes of the panel's discussion showed Thursday.

The guidelines calling for such a zone to be roughly 8 to 10 kilometers in radius from a nuclear power plant raise questions about whether the commission properly grasped the extent to which a nuclear disaster could affect surrounding areas.

In the ongoing crisis involving the Fukushima Daiichi nuclear power plant in Fukushima Prefecture, the government has designated a 20-km radius from the plant as a ''no-go'' zone where residents are barred from entry, and required most residents within 30 km to also evacuate.

Many municipalities across the country have based their emergency planning on the commission's guidelines, and have raised concerns and called for their review in the wake of the country's worst nuclear crisis, which was set off by a magnitude 9.0 earthquake and tsunami on March 11.

''The subject of reviewing the scope of the zone had not been a topic for a long time,'' an official at the commission's secretariat said. Noting that it should have been reconsidered earlier, the official said the commission plans to review it in the future.

The commission's panel discussed the matter in 2006 after the International Atomic Energy Agency gave a roughly 5 to 30 km radius from a plant as criteria for setting an emergency planning zone in which planning and preparation should be made in advance to take protective actions in cases of nuclear emergencies.

During its five sessions, however, the commission's secretariat explained that the emergency planning zone in the Japanese guidelines had a ''sufficient leeway,'' noting that the IAEA also allows each country to set one at its own discretion, according to the minutes.

Members of the panel did not suggest that the scope of the zone be reconsidered, concluding that ''pains should not have to be taken to include additional measures'' in the guidelines, the minutes showed.

The guidelines say that even in cases of an inconceivable disaster, ''no protective measures are needed outside (the emergency planning zone), such as staying indoors or evacuation.''

Following the current nuclear crisis, the government initially directed people within 20 km of the Fukushima plant to evacuate and those in a 20- to 30-km ring to stay indoors or voluntarily leave the area.

It has since expanded evacuation areas beyond the 20-km zone because of concerns over accumulated radioactive materials.

(Distributed by Kyodo News on May 19, 2011)