Tokyo Electric Power Co.’s stricken nuclear power plant was today rocked by two further explosions and a fire as workers struggled to avert the risk of a meltdown, heightening concern about radiation leaks.
A blast hit the Fukushima Dai-Ichi plant’s No. 4 reactor, where Tokyo Electric earlier reported a blaze, Japan’s Chief Cabinet Secretary Yukio Edano said at a briefing. Tokyo Electric said at a later briefing it is still investigating whether there were two explosions or one, and if their source was at the No. 4 unit. It didn’t explain the discrepancy with Edano’s comments.
Prime Minister Naoto Kan appealed for calm as he said the danger of further radiation leaks was rising at the crippled nuclear facility, 135 miles (220 kilometers) north of Tokyo. Sea water is being pumped to cool the reactors and prevent the uncontrolled release of radioactive material.
“The situation has taken a sharp turn for the worse,” said Vladimir Asmolov, deputy head of Russian nuclear utility Rosenergoatom, and a veteran of the team that battled the 1986 Chernobyl disaster. “Most important is to keep providing water and power supply to the station. There won’t be a leak of radiation comparable to Chernobyl.”
Asia’s biggest utility said earlier the containment chamber of the No. 2 reactor may be damaged after a blast at 6:14 a.m. and radiation leakage is possible. The explosion occurred near a suppression chamber that controls pressure in the No. 2 reactor’s core, Tokyo Electric said.
Tokyo Electric evacuated about 750 workers from the Nos. 1 to 3 reactors the plant after the explosion at the No. 2 unit and about 50 workers remain to manage the three reactors, Hikaru Kuroda, head of nuclear maintenance at the Japanese utility, said today.
Today’s blasts follow one at the No. 3 reactor yesterday after a buildup of hydrogen gas and a similar explosion at the No. 1 reactor on March 12. The utility’s stock fell by the daily limit of 25 percent in Tokyo.
The No. 2 reactor is still being monitored while the fire at the No. 4 unit appears to have been extinguished, Edano said. Temperature at the plant’s No. 5 and No. 6 reactors is also being monitored, he said.
Japan informed the International Atomic Energy Agency about the explosion at the No. 2 reactor and reported a fire at the No. 4 unit’s spent fuel pond that released radioactivity directly into the atmosphere, the IAEA said in a statement. “The Japanese authorities are saying that there is a possibility that the fire was caused by a hydrogen explosion,” the agency said.
About 140,000 people within a radius of 20 to 30 kilometers from the plant were ordered to stay indoors, Kyodo News reported, citing the prefecture government. The wind near the Fukushima plant was blowing from the east-north-east at noon, the Japan Meteorological Agency said.
Edano said earlier the vessel containing the radioactive core of the plant’s No. 2 reactor was damaged in today’s blast and radiation levels could harm public health.
As of 10.22 a.m. local time, radiation levels of 30 millisieverts were measured between the No. 2 and No. 3 reactors, while at the No. 3 reactor 400 millisieverts were detected, Edano said. “This is a level that could harm people,” he said.
Four-hundred millisieverts is 20 times the annual limit for nuclear industry employees and uranium miners, according to the World Nuclear Association. A radiation dose of 100 millisieverts a year is the lowest level at which any increase in cancer is evident, the London-based WNA said on its website.
While workers battled to head off the risk of a potential meltdown, the weather agency forecast snow in Fukushima prefecture, with the temperature dropping tomorrow to a low of minus 3 degrees Celsius (26.6 degrees Fahrenheit) in some areas.
About 1.3 million households were without power in Japan and 1.4 million had no running water, according to a government report on the earthquake.
The March 11 temblor -- updated yesterday to a magnitude of 9, from 8.9, by the U.S. Geological Survey -- and subsequent tsunami have led to what Kan called the country’s worst crisis since World War II. There have been 405 aftershocks since then. Stocks plunged and the Bank of Japan poured record funds into the economy.
More than 2,000 people are confirmed dead since the earthquake and tsunami hit the northeastern part of Japan, Deputy Cabinet Secretary for Public Relations Noriyuki Shikata said. “In the Kanto area, we do not have to be concerned about radiation levels affecting the human body at this juncture.”
The Kanto region encompasses seven prefectures, including Tokyo, and is home to about one-third of Japan’s 127 million people.