Criteria for evacuation and other actions against radiation exposure added

Nuclear agency updates disaster mitigation rules

Kyodo

The Nuclear Regulation Authority on Wednesday revised its disaster mitigation guidelines compiled in light of the Fukushima crisis by adding criteria for evacuation and other protective actions against radiation exposure.

According to the revised guidelines, people living within a 5-km radius of a nuclear power plant will be given iodine tablets, which help prevent thyroid cancer, ahead of time so they can promptly take the pills in the event of a fallout crisis.

People living outside the 5-km zone, meanwhile, will be ordered to evacuate if a radiation dose of 500 microsieverts per hour is detected, a tougher criteria than the International Atomic Energy Agency’s benchmark of 1,000 microsieverts.

Based on the guidelines, local governments hosting nuclear plants and those on the periphery are expected to craft their own disaster mitigation plans by March 18.

But there could be many cases in which local governments will not be able to finish their disaster prevention planning by the deadline because the regulatory body has seen a delay in its own work to revise the guidelines.

The authority decided on the original version of the disaster mitigation guidelines in October, featuring the expansion of the radius of areas that need to make special preparations to 30 km from an atomic plant. It had been working out the details since.

It received a total of 3,155 comments over its plan to revise the guidelines during the two weeks it solicited opinions from the public, many of them saying that the radiation level that forces residents to evacuate is too high and that evacuation zones are too small.

Some also said iodine pills should be distributed in advance to residents living outside the 5-km radius as well.

The number of comments the NRA received was larger than it expected. As no major revisions were observed in the guidelines based on the opinions received, people who came to watch Wednesday’s meeting of the NRA commissioners shouted out not to ignore public opinions.

Under the guidelines, the 5-km zone is called a “precautionary action zone” and residents will evacuate based on certain plant conditions before radioactive release starts, while the 5- to 30-km radius will be called an “urgent protective action planning zone,” from which residents will evacuate depending on actually measured dose rates or other data.

The revised guidelines added the numerical targets for evacuation for people outside the 5-km radius, such as the 500 microsieverts per hour benchmark, among other details.

At 20 microsieverts, consuming local food will be restricted and people will be asked to temporarily relocate within a week.

As for the handling of iodine tablets, the guidelines said preparations should be made so that residents living within the 5-km radius can take the pills as they evacuate. Local governments will issue instructions about the timing.