Kansai Electric's Mihama 3 cleared for extended operation

It will operate for up to 60 years.

Japan's Nuclear Regulation Authority (NRA) has approved an extension to the operating period for Kansai Electric Power's Mihama unit 3, enabling the plant to operate for up to 60 years.

The NRA's decision clears the 780 MWe pressurized water reactor to operate until 2036. It had previously been licensed until this year. Mihama 3 is the third Japanese unit to be granted a licence extension enabling it to operate beyond 40 years under revised regulations, following Kansai's Takahama 1 and 2 which received NRA approval in June.

Since May 2015, Mihama 3 has undergone special inspections and evaluations to assess the effects of aging management technology, and a long-term maintenance management policy has been drawn up for the plant. Kansai submitted its application to extend the unit's operating period in November 2015. The company submitted a subsequent amendment to the application to include its evaluation of the unit's earthquake resistance.

The NRA has also approved Kansai's revised nuclear facility safety policy concerning countermeasures for deterioration due to aging, which was submitted to the regulator at the same time as the operating period extension application.

Mihama 3 entered commercial operation in 1976, but remains off line following the 2011 Fukushima accident. The NRA has approved Kansai's plans to upgrade the plant, for which it submitted a restart application in March 2015. Kansai announced in March 2015 that Mihama units 1 and 2 would be permanently retired.