Aging reactors have been concerned because the three units at the Fukushima Dai-ichi plant that went into meltdown following the tsunami were built starting in 1967. Among other reactors at least 40 years old are those at Tsuruga and Mihama plants which were built starting in 1970.
Many more of the 54 reactors in Japan will reach 40 years in the near future, though some were built recently.
The government said that it plans to introduce legislation to require reactors to stop running after 40 years. Japanese media reported that the law may include the loophole to allow some old nuclear reactors to keep running if their safety is confirmed with the inspection.
The proposal could be similar to the law in the U.S., which grants the 40-year license and allows for 20-year extension. Such a renewal has been granted to 66 of 104 U.S. nuclear reactors. That process has been so simplified that many in the industry are already planning for the additional license of extension that could push the plants to operate for 80 years or even 100.
Japan does not currently have a limit on years of operation. It had planned to expand nuclear power before the meltdown, but has since ordered the new inspection which is to get community approval before they can be restarted. Under the new restriction only six Japanese reactors are currently running.
The Asahi newspaper reported Japan is likely to face a power shortage if it carries out the 40-year rule, which barring loopholes would force 18 more reactors to shut down by 2020, and another 18 by 2030.
But Japan doesn’t face a power shortage during the winter now and it still has time to build alternative electric generation systems.
Some critics mention that the loophole will allow old reactors to continuously run and the new rule distract the movement of stopping all the nuclear plants.
