Japanese officials battling to prevent a meltdown at a nuclear power station after Friday’s record earthquake are using seawater to try and cool a reactor and prevent damage to the chamber holding its radioactive core.
An explosion at Tokyo Electric Power Co.’s Fukushima Dai- Ichi nuclear power station yesterday destroyed the walls of its No. 1 reactor building and injured four people. A hydrogen leak caused the blast, which didn’t damage the steel chamber, Chief Cabinet Secretary Yukio Edano said at a briefing yesterday.
Asia’s biggest utility “has decided to fill the containment with seawater,” Edano said. Japan’s Nuclear Safety Agency couldn’t confirm a meltdown at the plant and monitoring around the reactor is showing that radiation is falling, spokesman Shinji Kinjyo said today.
Lack of adequate cooling for a reactor may cause a core meltdown, the most dangerous kind of nuclear power accident, releasing massive amounts of radiation, according to the U.S. Nuclear Regulatory Commission. The 1979 accident at the Three Mile Island reactor in Pennsylvania resulted in a partial meltdown, without a breach in the containment building, according to the commission.
“This case is quite difficult, it would be closer to what happened in 1979 at Three Mile Island,” Rafael Arutyunyan, first deputy director of Institute for Safety of Nuclear Energy, Russian Academy of Sciences, said on Russian television. “Only a small amount of active particles made it outside and were released into the atmosphere, so there were no consequences for the population. That’s the way we’re heading at the moment.”
Fuel Rods
Fuel rods at the reactor may be melting after radioactive Cesium material left by atomic fission was detected near the site, Nuclear and Industrial Safety Agency spokesman Yuji Kakizaki said yesterday.
“If the fuel rods are melting and this continues, a reactor meltdown is possible,” Kakizaki said. A meltdown refers to a heat buildup in the core of such intensity it melts the floor of the reactor containment housing.
Thousands were evacuated as workers vented radioactive gas from the plant in Fukushima, 220 kilometers (140 miles) north of Tokyo, and three people were hospitalized after being exposed to radiation. The death toll from a tsunami that swept over the northern coastline after the quake topped 600 and an estimated 4,000 were stranded in evacuation centers.
The 8.9 magnitude temblor forced Toyota Motor Corp. to shut some plants, shut down oil refineries and sparked a plunge in stocks. While the Finance Ministry said it’s too soon to gauge the quake’s economic impact, the Nikkei 225 Stock Average dropped 1.7 percent March 11.
Fukushima Dai-Ichi
The reactor at the Fukushima Dai-Ichi plant may remain shut for a year, Seth Grae, chief executive officer of Lightbridge Corp., a nuclear energy consulting firm whose staff previously inspected the Fukushima plant, said March 11 in an interview with Pimm Fox on Bloomberg Television’s “Taking Stock.”
“If they do lose several of those plants for a few months it could have a significant effect on Japan’s economy,” he said. “A trickle down could hit factories, slowing down Japan’s production.”
Tokyo Electric took almost two years to restart power generation at the Kashiwazaki Kariwa nuclear plant in the country’s northwest after a 6.8 magnitude temblor on July 16, 2007, caused a fire and radiation leaks at the world’s biggest atomic energy station.
Japanese Reactors
Nuclear energy provides almost 30 percent of Japan’s electricity, with total capacity of about 47,000 megawatts, with plans to increase that to 40 percent by 2017, according to the World Nuclear Association. The nation’s first reactor began operating in 1966 and there are 54 reactors in the country. A nuclear plant traditionally operates as many as 8 reactors.
Japan’s nuclear companies have been in talks to sell technology abroad, while Toshiba Corp. controls Westinghouse Electric Co., a U.S. maker of light-water nuclear reactors, which also has orders from China. Toshiba is bidding to build Turkey’s second nuclear power plant. A Japanese group in October also won a contract to build a nuclear plant in Vietnam.
Tokyo Electric started releasing radioactive gas and steam into the atmosphere about 9 a.m. local time yesterday to reduce pressure in the containment housing of the No. 1 reactor, company spokesman Akitsuka Kobayashi said. The utility has also started preparing to vent gas from containment areas of four reactors at the nearby Fukushima Dai-Ni nuclear plant, he said yesterday.
Evacuation Zone
Winds in the area of the Fukushima plant are blowing at less than 18 kilometers per hour mostly in an offshore direction, according to a 4 p.m. update from the Japan Meteorological Agency yesterday.
The government widened the evacuation zone around the damaged reactor to 20 kilometers from 10 kilometers, affecting thousands of people.
“When the pressure starts building up, the emergency procedure is to start venting,” Dave Lochbaum, director of the nuclear safety project at the Union for Concerned Scientists, said in a telephone interview. “They’ve essentially entered a beat the clock game. As long as there is no fuel damage, there will be radioactivity, but it will be very low.”
The plant’s operators need to connect to the electricity grid, fix emergency diesel generators or bring in more batteries to power a backup system that pumps the water needed to cool the reactor, said Lochbaum, a nuclear engineer who has worked at nuclear power plants for 17 years.
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