The Nuclear and Industrial Safety Agency proposed freezing studies by the Nuclear Safety Commission in 2006 on expanding the “disaster-mitigation zones” around nuclear plants during emergencies to bring Japanese regulations in line with international standards, according to email messages released Thursday by the commission.
NISA, part of the Ministry of Economy, Trade and Industry, argued that expanding the zones “could cause social unrest and increase popular anxiety,” the messages say.
The NSC, an independent body tasked with supervising nuclear safety regulation, did not enlarge the zones after considering the matter in 2006. It now appears its inaction resulted from NISA’s repeated complaints.
If the commission had followed through on expanding the zones, the chaotic developments surrounding the evacuations caused by the nuclear crisis that started last March in Fukushima Prefecture might have been reduced, sources said.
In March 2006, a panel at the NSC began studying whether to expand the size of the “priority disaster mitigation zone” beyond its current radius of 8 km to 10 km from a nuclear plant, the emails indicate.
While the zone’s current size was based on Japanese standards, new guidelines announced by the International Atomic Energy Agency called for designating areas within 5 km of a plant as the “top priority zone” and within 30 km as the “priority zone.
But NISA began to complain about the move in late April that year. In an email on April 24, for example, NISA asked the NSC not to use the expression “immediate evacuation” for the top priority zone, and then asked it to freeze the studies two days later.
Although the NSC initially rebuffed the agency’s repeated complaints, in November it eventually decided not to expand the zone.
Yoshinori Moriyama, a senior NISA official in charge of nuclear emergency measures, told reporters Thursday that NISA asked for the freeze to avoid a “hasty decision” that could have thrown local governments into “confusion.”
In light of the nuclear crisis caused by the meltdowns at the Fukushima No. 1 power plant after the March 11 earthquake and tsunami, the NSC decided to expand the priority disaster mitigation zone to a radius of 30 km and designate anything within 5 km of the plant as subject to immediate evacuation — the parameters it initially envisioned in 2006.