Japan’s nuclear regulator allows extending operations for 2 aging units of Takahama NPP


With nuclear power emerging as a crucial technology amidst the global climate crisis, Japan’s Nuclear Regulation Authority (NRA) late last month approved the operation of the aging units 3 and 4 at the Takahama nuclear power plant (NPP) in Fukui prefecture for a further 20 years. 

The NRA’s decision makes the two reactors at the facility, operated by the Kansai Electric Power Company, the seventh and eighth reactors nationwide eligible for extensions after 40 years of operations. The Takahama NPP unit 3 and 4 reactors will reach their 40th anniversaries in January and June of 2025, respectively.  

The Kansai Electric Power Company applied for the extension in April last year. The company said it had carried out special inspections and evaluations of the two units, and had not found any issues likely to cause problems if the operating period were to be extended to 60 years. 

According to local media reports, NRA Chairman Shinsuke Yamanaka said at a meeting that nuclear reactor pressure vessels tend to become brittle due to radiation, but an official at the organisation’s secretariat said the reactors had been evaluated carefully and that there was “no problem.” 

The Takahama plant houses four pressurised water reactors (PWRs). Takahama 1 and 2 – both 780 MW – entered commercial operation in 1974 and 1975, respectively, while units 3 and 4 – 830 MW each – began commercial operation in 1985. Takahama 1 and 2 became the first Japanese units to be granted a license extension beyond 40 years under the revised regulations. 

The Takahama units’ 1 and 2 reactors were approved in 2016 to operate beyond 40 years from their start date. In 2023, both reactors were restarted for the first time since the 2011 Fukushima nuclear accident caused by the tsunami that hit the coast of Japan.  

Following the Fukushima nuclear disaster, the operational lifespan of Japan’s nuclear reactors was limited to 40 years under much stricter safety protocols, with extensions to 60 years possible pending approval. 

“We will continue to strive to improve the safety and reliability of our nuclear power plants and utilise nuclear power generation as an important source of energy,” the Kansai Electric Power Company said in a statement. 

In December 2022, the NRA approved a draft of a new rule that would allow reactors to be operated for more than the current limit of 60 years. Under the amendment, the operators of reactors in use for 30 years or longer must formulate a long-term reactor management plan and gain approval from the regulator at least once every 10 years if they are to continue to operate.  

The new policy will effectively extend the period reactors can remain in operation beyond 60 years by excluding the time they spent offline for inspections from the total service life. 

The legislation was approved by Japan’s Cabinet and enacted in May 2023. It comes into effect in June 2025. Under the new policy, which describes nuclear power as “a power source that contributes to energy security and has a high decarbonisation effect”, Japan will maximise the use of existing reactors by restarting as many of them as possible and prolonging the operating life of aging ones beyond the current 60-year limit. 

Reactors approved under the previous framework will need to gain permission again from the regulator NRA by June 2025.