TOKYO (Kyodo) -- Japan's nuclear watchdog formally decided Wednesday that a reactor in central Japan has failed to pass a safety review needed for its restart, in the first such case since the regulatory body's founding after the 2011 Fukushima nuclear crisis.

The Nuclear Regulation Authority said it confirmed its decision made in August not to approve the safety of the No. 2 reactor at the Tsuruga plant, operated by Japan Atomic Power Co., due to the possibility that an active fault runs underneath the offline unit. The NRA had also solicited public comments.

In quake-prone Japan, building reactors or other important facilities directly above faults is prohibited.

A safety review team of the NRA concluded in July this year it could not rule out the possibility that an active fault located around 300 meters north of the reactor building stretched right below the facility.

So far, of 35 reactors nationwide, including those under construction, 27 have applied for a safety review and 17 have cleared it.

Japan Atomic Power first applied for the safety screening of the unit in 2015 despite an NRA experts' investigation reporting the existence of an active fault underneath the unit in 2013.

Proceedings for the assessment were suspended twice after it was revealed that Japan Atomic Power had submitted documents that included inaccuracies and data rewritten without approval. It reapplied in August last year.

Japan revamped its regulatory setup by launching the NRA in 2012 and also introduced a set of new safety requirements in July 2013 to reflect the lessons learned from the disaster at Tokyo Electric Power Company Holdings Inc.'s Fukushima Daiichi plant, triggered by a massive earthquake and tsunami in March 2011.