Tokyo ( CNN ) -- A Japanese nuclear plant will shut down its reactors after the country 's prime minister warned it was vulnerable to natural disasters , its owner announced Monday . The Chubu Electric Company said it will take two of its reactors at the Hamaoka nuclear plant off line and not bring a third back on line , effectively shutting down the plant . In a statement , the company said , `` At the May 9 , 2011 meeting of the Board of Directors , Chubu Electric Power Company , Inc. , has decided to suspend operations of Hamaoka Nuclear Power Plant until further measures to prevent tsunami ( damage ) are completed , as requested by the prime minister . '' Prime Minister Naoto Kan said last week that the plant -- located on the Pacific coast in Omaezaki , southwest of Tokyo -- could produce `` grave damage to Japan '' similar to the problems at the Fukushima Daiichi nuclear power plant , and wanted earthquake and tsunami protections put in place . Akihisa Mizuno , president of Chubu Electric , said safety was the company 's first priority . Meanwhile , workers reentered the No . 1 reactor building at the crippled Fukushima Daiichi nuclear power plant Monday as they try to restore its cooling system , the plant 's operator said . Nine Toyko Electric Power Co. employees and two representatives from Japan 's Nuclear and Industrial Safety Agency spent about 30 minutes in the building measuring radiation levels . On Thursday , workers went into the damaged facility for the first time since a magnitude-9.0 earthquake and ensuing tsunami in March . They installed a ventilation system that is filtering radioactive substances from the air . The purpose of Monday 's visit was to see how successful the system has been . Once the radioactive contamination in the air is lowered enough , workers will be able stay in the building longer to install a cooling system that Tokyo Electric wants to use to perform a cold shut down of the reactor . Cooling systems at Fukushima Daiichi , about 240 kilometers ( 150 miles ) north of Tokyo , were knocked out by the devastating tsunami that struck Japan 's Pacific coast after a massive earthquake March 11 . The disaster triggered the worst nuclear accident since Chernobyl as the cores of reactors 1-3 overheated and spewed huge amounts of radioactive contamination across the surrounding area . The buildings that house reactors 1 and 3 were blown apart by hydrogen explosions in the first days of the crisis . Another hydrogen buildup is believed to have ruptured a water reservoir beneath the No . 2 reactor . In April , Tokyo Electric laid out a six- to nine-month timetable for winding down the crisis and bringing the reactors to a complete shutdown . The disaster has led to mandatory evacuations of about 78,000 people living within 20 kilometers ( 12.5 miles ) of the plant . People living another 10 kilometers away -- or at least another 60,000 people -- have been ordered to remain sheltered . Yoko Wakatsuki , Kyung Lah and Junko Ogura contributed to this report .
Chubu Electric Company says it is shutting down reactors at the Hamaoka nuclear plant . Ventilating the reactor building at Fukushima Daiichi will allow employees to work there longer . An earthquake and tsunami hit the nuclear facility on March 11 . - The U.S. Nuclear Regulatory Commission has approved a plan for new safety measures in response to Japan's 2011 disaster, including more stringent inspections of spent fuel pools that are used as cooling systems after an accident or