TOKYO – Atomic power will remain a major part of Japan's energy policy despite the ongoing crisis at one tsunami-crippled plant and a looming shutdown of another while its quake protections are improved, a government official said Sunday.
Deputy Chief Cabinet Secretary Yoshito Sengoku also said no reactors other than the three units at the Hamaoka power plant in central Japan would be shuttered over quake and tsunami concerns.
There is "no need to worry" about other reactors, Sengoku said. "Scientifically, that's our conclusion at the moment."
The government evaluated Japan's 54 reactors for quake and tsunami vulnerability after the March 11 disasters that heavily damaged the Fukushima Dai-ichi plant in northeast Japan.
Chubu Electric Power Co., which runs the Hamaoka plant, is still considering the government's request to shut the reactors while the utility builds a seawall and improves backup systems to protect the reactors from a major earthquake and tsunami.
Nuclear energy provides more than one-third of Japan's electricity, and shutting the three reactors would likely worsen power shortages expected this summer. Already, buildings have reduced lighting, stores have trimmed service hours and subway operators have shut air conditioning in a conservation effort in the capital region since the March 11 disasters.
After an executives' meeting Saturday failed to finalize a decision, Chubu chairman Toshio Mita left for Qatar to negotiate for liquefied natural gas supplies to cover the shortfall, company official Tatsuo Sawaki said Sunday.
The three reactors account for more than 10 percent of the company's power supply, company officials said.
Chubu Electric has estimated maximum output of about 30 million kilowatts this summer with the three Hamaoka reactors running, with estimated demand of about 26 million kilowatts.
"It would be tight," said another Chubu official Mikio Inomata, adding that officials are discussing possibilities of boosting output from gas, oil and coal-fueled power plants and buying power from other utility companies.
The Hamaoka plant is a key power provider in central Japan, including nearby Aichi, home of Toyota Motor Corp.
The plant about 125 miles (200 kilometers) west of Tokyo has been known as Japan's "most dangerous" nuclear plant as it sits in an area where a major quake is expected within decades. About 79,800 people live within a 6-mile (10-kilometer) radius.
Prime Minister Naoto Kan noted Friday that experts estimate a 90 percent chance of a quake with a magnitude of 8.0 or higher striking that region within 30 years.
"That makes Hamaoka an exceptional case," Kan told reporters Sunday. He urged Chubu executives "to understand."
Since the March 11 disasters, Chubu Electric has drawn up safety measures that include building a 40-foot-high (12-meter) seawall nearly a mile (1.5 kilometers) long over the next two to three years, company officials said. Chubu also promised to install additional emergency backup generators and other equipment and improve the water tightness of the reactor buildings.
The Hamaoka plant lacks a concrete sea barrier now. Sand hills between the ocean and the plant are up to 50 feet (15 meters) high, deemed enough to defend against a tsunami around 26 feet (8 meters) high, officials said.
The operator of the Fukushima nuclear plant, Tokyo Electric Power Co., has said the tsunami that wrecked critical power and cooling systems there was at least 46 feet (14 meters) high.
The March 11 quake and tsunami left more than 25,000 people dead or missing on the northeast coast and triggered the worst nuclear crisis since Chernobyl in 1986.
On Sunday, the government approved TEPCO's plan to allow workers return to Fukushima Dai-ichi's No. 1 reactor building to install a new cooling system after its main door was left open overnight for ventilation, said Hidehiko Nishiyama, spokesman for the Nuclear Industry and Safety Agency.
Radioactivity inside the building has fallen to levels deemed safe for people wearing protective suits to enter, Nishiyama said. Workers rapidly installed air filtering equipment in there Thursday — their first entry since shortly after the tsunami.
"We judge the environment has improved to one that allows people to enter and work," Nishiyama said.
Workers later Sunday removed air-filtering ducts and machines, leaving holes on the wall unplugged and the door open until Monday morning, when air monitoring staff are to enter for a final check, TEPCO said.
TEPCO spokesman Junichi Matsumoto said air coming into the building through the entrance may rise and push out radioactivity through the damaged roof, but the amount would be too low to cause health risks. The building largely lost its roof in a hydrogen explosion on March 12.
Mari Yamaguchi can be reached at http://twitter.com/mariyamaguchi