Japan's parliament passed a bill Wednesday that allows nuclear reactors in the country to be operated beyond the current limit of 60 years to help cut carbon emissions and ensure an adequate national energy supply despite lingering concerns over the safety of aging reactors.

The law on power sources for green transformation and decarbonization amends five laws associated with energy at once, including the electricity business law, under which the life span of reactors will be regulated.

Some lawmakers and citizens said the bill was hastily passed without adequate deliberation, and public concerns about the safety of aging reactors were not properly addressed.

Economy, Trade and Industry Minister Yasutoshi Nishimura told reporters that the government will continue holding nationwide in-person or online briefing sessions to deepen public understanding of the law.

A law on power sources for green transformation and decarbonization is enacted during a plenary session of the House of Councillors in Tokyo on May 31, 2023. (Kyodo)

In Japan, fossil fuel-fired plants generate roughly 70 percent of the nation's total electricity. The 2011 Fukushima nuclear crisis led to the closure of all nuclear reactors, with most reactors remaining offline as they must meet stricter safety standards introduced after the disaster in order to restart.

Prime Minister Fumio Kishida said last summer the government will take the necessary steps to push ahead with the restart of more units, instructing the government to look into how the country can maximize its nuclear energy facilities most effectively.

The tougher safety standards under the reactor regulation law limit the service period of a nuclear reactor to 40 years, in principle, and up to 60 years if proper safety upgrades are made.

But under the new rules, nuclear reactors may be granted additional operating years in effect as their offline periods will not be counted against their total service time provided the periods are due to reasons beyond a utility's control, such as safety reviews needed for a restart and court-ordered suspensions.

The industry minister will give approval for extending the life of nuclear reactors on a case-by-case basis.

In addition, under the amended reactor regulation law, the country's Nuclear Regulation Authority will check the condition of reactors and related facilities at least every 10 years after 30 years of operating to ensure the safety of old facilities.

The government has said it will decide on the details of standards for granting extensions before the law takes effect, while critics have pointed out that specific ways to assess the age-related deterioration of reactors beyond 60 years of operation, among other issues, remain unclear.

Russia's war in Ukraine, which started in late February 2022, drove energy prices sharply higher and threatened stable energy supplies for Japan -- a resource-scarce country that relies heavily on fossil fuel imports -- prompting officials to look into greater use of nuclear power.

Related coverage:

Japan Cabinet OKs bills to extend nuclear reactor life beyond 60 yrs