Japan's ageing Hamaoka nuclear power plant, located near a tectonic faultline southwest of Tokyo, completed the shutdown of all its reactors Saturday to prevent any accident due to a natural disaster.
The plant's number-five reactor stopped generating power and was shut down at 1:00 pm (0400 GMT), Chubu Electric Power Co. spokesman Hiroaki Oobayashi said.
"The shutdown was confirmed after we inserted all 205 control rods into the reactor," he added.
Prime Minister Naoto Kan had earlier called for its closure, eight weeks after a massive earthquake and tsunami damaged the Fukushima Daiichi nuclear plant northeast of Tokyo, sparking the world's worst atomic crisis in 25 years.
The Hamaoka plant, located 200 kilometres (125 miles) southwest of Tokyo, has five reactor units, but only two have been running recently -- numbers four and five. Reactor number four was suspended on Friday.
Reactors one and two, built in the 1970s, were stopped in 2009, and three is undergoing maintenance.
Seismologists have long warned that a major earthquake is overdue in the Tokai region southwest of Tokyo where the Hamaoka plant is located.
Hamaoka accounts for almost 12 % of the output of Chubu Electric, which serves a large part of Japan's industrial heartland, including many Toyota auto factories.
Kan said the plant should stay shut while a higher sea wall is built and other measures are taken to guard it against a major quake and tsunami. Local media said the suspension would last about two years.