TOKYO — Japan's Cabinet approved bills Tuesday aimed at bolstering nuclear safety regulations following last year's Fukushima disaster, including one that would put a 40-year cap on the operational life of nuclear reactors.
The approval came as International Atomic Energy Agency experts generally endorsed "stress test" results at two idled reactors in western Japan, bolstering the Tokyo government's efforts to restart the facility, though the IAEA team said some safety measures needed clarification.
Japan currently has no legal limit on the operational lifespan of its 54 reactors, many of which will reach the 40-year mark in coming years. One reactor at the Fukushima Dai-ichi plant had been in use 40 years when the tsunami struck last March.
The legislation, which still needs parliamentary approval to take effect, does allow for an extension of up to 20 years. Critics have blasted that exception as a loophole, but officials have said extensions will be rare and require strict safety standards.
Also Tuesday, the chief of Kawauchi village, which straddles the exclusion zone around the Fukushima plant, told more than 2,500 residents that returning to the town areas outside the no-go zone was safe, following extensive decontamination of radiation fallout.
Most residents whose homes were outside the exclusion zone chose to leave when the Kawauchi town hall moved to Koriyama City, about 40 kilometers (25 miles) away.
Mayor Yuko Endo said offices, schools and other public facilities will restart in April. Kawauchi is the first of nine townships whose administrative functions shifted elsewhere to make such an announcement.
"I encourage you to go home," Endo told a televised news conference from the Fukushima government office. "Those of you who can return now, please do so. If you are still worried, you can wait a little until you feel comfortable."
About one-third of Kawauchi village lies within the 12-mile (20-kilometer) exclusion zone and remains off-limits.
Since the government announced in December that the Fukushima plant was stable, guidelines have been made for affected towns that would allow residents to return to areas with contamination levels below 20 millisieverts per year, which it says is safe, though further reduction is recommended.
Another bill approved by the Cabinet would create a new nuclear regulatory agency under the Environment Ministry that would unify nuclear safety and regulatory bodies. The Nuclear and Industrial Safety Agency is currently under the Ministry of Economy, Trade and Industry — which also promotes nuclear energy. Critics say that placement has contributed to lax supervision of the industry.
After the Fukushima accident, Japan reversed its nuclear energy policy and now aims to reduce its dependency on atomic power. Officials say capping the lives of reactors at 40 years is consistent with that policy.
Still, Prime Minister Yoshihiko Noda has said Japan must rely on nuclear energy during the transition and idled reactors deemed safe after inspections need to be restarted.
The government has ordered reactors shut down since the meltdowns at Fukushima to undergo "stress tests" before they can be restarted. But passing the tests may not lead to a quick startup because of deep safety concerns in local communities hosting the reactors.
With only three of the country's 54 reactors online, officials are desperately trying to avoid a power crunch. One of the three operating reactors will go offline for regular checks next month, and Japan will have no operating reactors by the end of April.
Last week, a 10-member IAEA delegation inspected the Ohi No. 3 and No. 4 reactors at a nuclear plant in Fukui prefecture — a rural area where 13 reactors are clustered around a bay. The reactors have undergone stress tests, which are supposed to assess whether they can withstand earthquakes, tsunamis, loss of power or other emergencies, and to suggest changes to improve safety.
The IAEA team was invited by Tokyo to visit the plant in a step seen as an attempt to drum up support for the government's safety campaign.
In a preliminary assessment Tuesday, the team said that Japanese nuclear safety officials' instructions to their operator, Kansai Electric Power Co., and the review process for the tests were "generally consistent" with IAEA safety standards.
However, the team said authorities should clarify the stress tests' goals and better define what constitutes the safety margins within which plants would be able to tolerate disasters. It also said the nuclear safety agency, or NISA, still needs to confirm certain improvements to safety before allowing the facility to resume operation.
Mission leader James Lyons said that the team was "satisfied with the work they had done as part of their primary assessment" but that there was room for improvement.
NISA chief Hiroyuki Fukano welcomed the IAEA review, saying authorities were "encouraged" that stress tests were deemed valid.
Critics, however, say the tests are meaningless because they have no clear criteria, and view the IAEA as biased toward the nuclear industry.