The Nuclear Regulation Authority set new guidelines Wednesday for fallout disaster mitigation measures, expanding the distance where special preparations are required to 30 km from atomic power plants.
While details need to be fleshed out, such as specific criteria for evacuation, the guidelines were revised to meet international standards and rewritten in plain language to be more easily understood, the NRA said. The NRA’s predecessor was harshly criticized over its handling of the Fukushima crisis.
Based on the guidelines and other information provided by the NRA, local governments hosting nuclear plants and those on the periphery are expected to craft their own disaster mitigation plans and set the scope of the emergency zones by March.
“Compiling the guidelines is not the end of the work. . . . The guidelines will prove useful after (disaster mitigation) plans are created and drills are held,” NRA Commissioner Kayoko Nakamura said, adding the guidelines should be constantly reviewed.
The existence of disaster mitigation plans is not a legal requirement when resuming operation of nuclear reactors, but NRA Chairman Shunichi Tanaka has said it will be difficult for reactors to be brought back online unless local governments devise plans in line with the new guidelines.
The most notable change is that emergency zones have been widened to a 30-km radius around each nuclear plant, from 10 km. A “precautionary action zone” extends about 5 km from a plant and residents will evacuate based on certain plant conditions before a radioactive release starts, while an “urgent protective action planning zone” covers a radius of about 30 km and residents will evacuate depending on radiation levels or other information.
Recently announced projections for the spread of radiation showed that points more than 30 km away from some nuclear plants could see radiation levels reach 100 millisieverts a week into a meltdown crisis, a level where evacuation is recommended. Tanaka has said 30 km is enough for emergency zones, but local governments may expand the zones further.
Due to the expansion of the zones, the number of prefectures that include such areas will increase to 21 from 15. The number of people who could be affected will total 4.8 million.
The NRA has to set criteria for starting evacuations and taking other protective action to enable swift decision-making, but the guidelines state it plans to establish them by the end of this year.
NRA Commissioner Toyoshi Fuketa stressed the need to hold substantial discussions on the issue, saying the criteria are “extremely important to make the guidelines workable.”
Other issues that need to be studied include whether to distribute iodine tablets in advance to prevent residents from developing thyroid cancer.