New policy on nuclear safety regulation could limit the operational life of Japanese nuclear plants to 40 years and require operators to prepare for severe accidents, Japan’s government announced on Friday. If the new law is passed, at least 13 plants, as well as the six Fukushima Daiichi reactors, will be shut down per the 40-year age limit over the next 10 years. Forty-eight of the country’s 54 reactors are currently on hiatus pending rigorous safety checks.

The limit could ease public distrust toward nuclear power following the Fukushima catastrophe and help persuade citizens to allow resumed operation of the 48 reactors. Japan has been struggling to meet power demand following closure of its nuclear power plants.

The limit was set in a bill that will go before both houses of the National Diet, Japan’s bicameral legislature, which will reconvene this month. It could be passed into law early this year.

Current law requires utilities to conduct safety checks on reactors at 30 years, and again at 40 years, to stay in operation. Though limiting reactor lifetimes to 40 years, the government may still approve extensions on a case-by-case basis under the new law.

Meanwhile, the Nuclear Safety Agency Preparation Office, which was tasked with overhauling nuclear safety regulation, plans to launch a new safety and regulatory authority, the Nuclear Safety Agency, in April. That agency will be placed under the Environment Ministry, not the Ministry of Economy, Trade, and Industry.

The Denki Shimbun newspaper quoted the Nuclear Safety Agency Preparation Office as saying that the 40-year period was an assessment guideline for reactor pressure vessel embrittlement due to neutron irradiation. Fukushima Daiichi Unit 1, a Mark I boiling water reactor that started commercial operation on March 26, 1971, was a few days short of the 40-year age limit when a massive quake and subsequent tsunami damaged the reactor on March 11, 2011.

Daiichi Units 2 and 3, which also saw core meltdown, began operating in 1974 and 1976.

Sources: POWERnews, METI, Denki Shimbun