A working group under the government’s nuclear safety panel will expand priority areas that should be prepared for possible atomic accidents to a 30-km radius of a nuclear power plant from the current 8 to 10 km.
The group is reviewing areas where enhanced disaster-prevention measures should be taken, after the nuclear crisis at the Fukushima No. 1 nuclear power plant led the government to set a 20-km radius of the plant as a no-entry zone and advised people living in areas outside the zone where high radiation doses had been detected to evacuate.
But the move is expected to increase expenses to implement disaster-prevention measures nationwide, suggesting the heavy burden required to operate nuclear plants.
Under the plan, unveiled Tuesday, the government would replace the current Emergency Planning Zone with two types. The first, a Precautionary Action Zone covering a 5-km radius of a nuclear power plant, would require residents to immediately evacuate in the event of a rapidly developing nuclear accident.
The other, an Urgent Protective Action Planning Zone, would cover a 30-km radius where residents would be asked to be prepared to evacuate depending on the situation. The areas should also be prepared to check the radiation level swiftly by setting up monitoring posts.
As the Fukushima crisis resulted in the release of radioactive substances beyond the 30-km radius, the plan also cited the need to designate another area where people may be asked to stay indoors or ingest stable iodine to prevent radioactive iodine from accumulating in the thyroid and increasing the risk of thyroid cancer.
The zone is called a Plume Protection Planning Area and should cover a 50-km radius from the plant, the plan said.
The proposed expansion to a 30-km range means that heavily populated prefectural capitals such as Ibaraki’s Mito, and Kyoto and Kagoshima, would be included, while the total population of cities, towns and villages involved under the new guideline, including the plume protection area, would stand at nearly 20 million.
The nuclear crisis at the Tokyo Electric Power Co. plant was triggered by the devastating March 11 earthquake and tsunami, and resulted in the nuclear fuel meltdown of reactors 1, 2 and 3.