The unit was shut for performing regular inspections legally mandated for every 13 months, AFP reported.
Kansai Electric will also perform inspections at Unit 4 of the Ohi nuclear power plant, which is scheduled on 15 September 2013.
Kansai Electric said that Units 3 and 4 of the nuclear plant will be assessed under a set of guidelines recently framed by the Nuclear Regulation Authority of Japan.
The two reactors were restarted, in spite public opposition, in July 2012 after passing safety tests, ending a brief period in which no atomic power was generated in Japan.
Closure of these units will be the second time that all the commercial nuclear reactors in Japan are offline at the same time since the 2011 Fukushima disaster.
