Japanese Nuclear Plant Radiation Recedes as Engineers Restore Water Level

March 15 (Bloomberg) -- Tokyo Electric Power Co. engineers at a nuclear plant restored water to safe levels, helping drive down radiation after residents within 30 kilometers (19 miles) were ordered inside to avoid contamination.

Water supply at reactors No. 1 and No. 3 stabilized and radiation readings at the front gate of the plant dropped to a level that isn’t “harmful to the human body,” Chief Cabinet Secretary Yukio Edano said this afternoon in Tokyo. Separately, Tokyo Electric said it hadn’t decided whether to bring workers after the utility evacuated 750 of its 800 employees following this morning’s blast.

Prime Minister Naoto Kan, facing a nation reeling from its strongest earthquake on record, said the danger of further radiation leaks increased at the nuclear facility, located 135 miles north of Tokyo. That sent the nation’s Topix stock index to its biggest two-day drop since 1987 as concern grew over the government’s ability to contain the crisis.

“Most important is to keep providing water and power supply to the station,” said Rosenergoatom deputy head Vladimir Asmolov, who’s headed to Japan to fight the crisis and was part of the team that battled the 1986 Chernobyl disaster. “There won’t be a leak of radiation comparable to Chernobyl.”

Two Holes

The building that houses the No. 4 reactor at Tokyo Electric’s Dai-Ichi nuclear plant has two holes in it and water in the spent fuel pool may be boiling, Hidehiko Nishiyama, deputy director-general of Japan’s Nuclear and Industrial Safety Agency, said in Tokyo.

“If it is boiling, the water level will drop and hydrogen will be released,” Nishiyama said.

A Tokyo Electric worker at the Fukushima nuclear plant is being treated for radiation exposure, said Toshiriro Bannai, director of international affairs for the Tokyo-based agency.

In Ibaraki prefecture, about 43 miles south of the nuclear plant, radiation levels surged to as high as 3,560 nanosieverts at 8:10 a.m. before falling to 821 nanosieverts per hour as of 3 p.m., the Ibaraki government said in the release today. That compares with 50 nanosieverts as of 9:30 a.m. on March 13, when the measurements began, according the statement.

“The radiation levels are above normal, but at most only about one-10th of a chest X-ray and are not harmful to the health,” the government said in a separate statement today.


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 was possible. The explosion occurred near a suppression chamber that controls pressure in the No. 2 reactor’s core, Tokyo Electric said.

Photographer: Tomohiro Ohsumi/Bloomberg

A file photograph from 2010 shows employees and inspectors from the International Atomic Energy Agency (IAEA), checking a rod containing plutonium-uranium mixed oxide, known as MOX, fuel being loaded into the No. 3 reactor at Tokyo Electric Power Co.'s Fukushima Dai-Ichi nuclear power station. Close

A file photograph from 2010 shows employees and inspectors from the International... Read More

Photographer: Tomohiro Ohsumi/Bloomberg

A file photograph from 2010 shows employees and inspectors from the International Atomic Energy Agency (IAEA), checking a rod containing plutonium-uranium mixed oxide, known as MOX, fuel being loaded into the No. 3 reactor at Tokyo Electric Power Co.'s Fukushima Dai-Ichi nuclear power station.

Tokyo Electric evacuated about 750 workers 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.

Hydrogen Blast

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. The wind near the Fukushima plant was blowing southward 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.

At 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.

Uranium Miners

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.

The Dai-Ichi plant’s No. 2 reactor experienced a drop in water levels after a power outage on June 17, according to a Tokyo Electric statement at the time. The plant used an alternative pump to add water to the reactor to return it to normal water levels, it said.

Iwaki City council member Kazuyoshi Sato asked Tokyo Electric President Masataka Shimizu to investigate the causes to prevent a repeat occurrence, the current crisis shows adequate measures weren’t taken, he said.

‘Too Much Faith’

“Tokyo Electric and the government’s Nuclear and Industrial Safety Agency had too much faith and confidence in the safety of the plant and were lax in their response,” he said by phone today.

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 (8301) 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.

To contact the reporters on this story: Tsuyoshi Inajima in Tokyo at tinajima@bloomberg.net; Michio Nakayama in Tokyo at mnakayama4@bloomberg.net; Shigeru Sato in Tokyo at ssato10@bloomberg.net

To contact the editor responsible for this story: Amit Prakash at aprakash1@bloomberg.net

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