Re: Grayish smoke seen billowing from Fukushima No. 3 reactor building
Posted by JAC on 3/21/2011, 5:44 am



Tokyo (CNN) -- Gray smoke spewed Monday out of the Fukushima Daiichi nuclear power plant's No. 3 reactor, a setback that came despite fervent efforts to prevent the further release of radioactive materials at the stricken facility.

Those who had been working nearby were evacuated to safety shortly after the smoke was spotted around 4 p.m. Monday , a Tokyo Electric Power Company official told reporters.

This is the same reactor that has been authorities' top priority -- and concern -- in recent days.

Hidehiko Nishiyama, an official with Japan's nuclear and industrial safety, said measurements taken soon after the smoke was spotted did not indicate any spike in radiation. He said that there was no evident explosion, and no one was reported injured.

Explainer: Producing nuclear energy About two hours later, Nishiyama said it wasn't known what was causing the smoke or what exactly was burning. He explained that it emanated from the building's southeastern side, where the reactor's spent nuclear fuel pool is located.

For days, authorities have been working fervently to fill that pool with water -- fearful that the evaporation of water and high temperatures could expose fuel rods within and lead to the release of more radioactive vapors.

Another Japanese nuclear and industrial safety official estimated that, between roughly 9 p.m. Sunday to 4 a.m. Monday, 1,170 tons of water were sprayed on the reactor and its fuel pool.

Earlier, officials said that they were monitoring that reactor to determine whether to release gas in order to reduce mounting pressure in the containment vessel. The pressure buildup, specifically from excess hydrogen gas, had caused explosions at that reactor and at the Nos. 1 and 2 reactors. Late last week, three holes apiece were drilled into the Nos. 5 and 6 reactors in order to alleviate pressure.

This development came shortly after a Tokyo Electric official told CNN that electrical cables had been laid to connect the No. 3 reactor and the neighboring No. 4 reactor with an outside power source.

That meant that power could now be funneled to all six of the plant's reactors for its cooling systems. But electricity was still not moving to Nos. 1, 2, 3 and 4, because the March 11 mammoth earthquake and subsequent tsunami -- including seawater that had rushed into the reactors -- had damaged numerous pumps and other apparatus. The Tokyo Electric official said that spare parts were being brought in, so that everything could work again.

The disaster has killed more than 8,600 people and left more than 13,000 missing, many of them killed soon after a wall of water rushed in with the tsunami. Ever since, authorities have been work to avert further crisis -- and prevent more deaths -- at the Fukushima Daiichi plant, some 240 kilometers (150 miles) north of Tokyo.

TEPCO official reports on power plant Those efforts include a move to possibly encase one or more of the reactors in concrete, a last-ditch effort similar to what was done after the 1986 meltdown at the Chernobyl nuclear plant in the former Soviet Union -- considered the worst nuclear disaster at a plant.

On Monday, an official with Japan's nuclear and industrial safety agency told reporters that tests are expected to be conducted in the afternoon on how to use what he called a "concrete pump engine."

The engine would pump a mix of mortar and water into the reactor's spent nuclear fuel pool and containment vessel, the official said. The pool contains nuclear fuel rods that could give off radioactive material, if exposed and overheated, while the containment vessel is a steel and concrete shell that insulates radioactive material inside.

While he did not indicate when or even if the concrete pump would be used, the official did say the target would be the plant's No. 4 reactor. In just over two hours on Monday morning alone, 13 fire engines sprayed about 90 tons toward that reactor in an attempt to cool it down.

A Tokyo electric official told CNN that six workers trying to restore electricity to that reactor have been exposed to more than 100 millisieverts of radiation. For reference, an individual in a developed country naturally is exposed to 3 millisieverts of radiation a year -- though Japan's health industry has set a 250 millisievert limit for those trying to combat the crisis at the Fukushima plant.

These efforts came as concerns remained high about the impact that already emitted radiation has had on food, water and people within range of the Fukushima facility.

Very small amounts -- far below the level of concern -- of radioactive iodine have been detected in tap water in Tokyo and most prefectures near the plant.

The health ministry said levels of radioactive iodine three times greater than the regulated standard were found in drinking water in a village near the plant and asked residents not to drink from the tap, Kyodo News reported Sunday.

The Japanese government has banned the sale of raw milk from Fukushima Prefecture, where the plant is located, and prohibited the sale of spinach from neighboring Ibaraki Prefecture after finding levels of radioactive iodine and cesium higher than government standards, the country's health ministry reported. And officials in Fukushima halted the distribution of locally grown vegetables outside the prefecture.

Edano said the contaminated milk detected in Fukushima Prefecture had not been distributed or sold.

On Saturday, officials said tainted milk was found 30 kilometers (18 miles) from the plant, and spinach was collected as far as 100 kilometers (65 miles) to the south, almost halfway to Tokyo.

The latest results accumulated and posted online by Japan's education, science and technology ministry showed slight but notable upticks in airborne radiation readings around Japan in recent days. But even the highest readings, .11 millisieverts some 30 kilometers northwest of the plant, were still considered significantly below what's considered dangerous to humans.

Nature has helped to minimize such airborne exposure since the quake, as winds from the northwest have blown many emissions from the plant out to sea.

But the wind direction is expected to change through Wednesday, potentially pushing more of the material to the southwest and over land.

"People are watching," said Akira Shioi, who lives in Kawasaki. "And people have greater concern than ever about the nuclear power plant incident."





http://www.cnn.com/2011/WORLD/asiapcf/03/21/japan.nuclear.reactors/index.html?on.cnn=1#

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Grayish smoke seen billowing from Fukushima No. 3 reactor building - JAC, 3/21/2011, 5:32 am
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