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Showing posts with label Chernobyl. Show all posts
Showing posts with label Chernobyl. Show all posts

Thursday, March 31, 2011

Radiation in tunnel water at Japan plant 10,000 times over normal

Thu Mar 31, 2011 3:08pm GMT

TOKYO, March 31 (Reuters) - Radiation in water of an underground tunnel outside a turbine building of No.2 reactor at Japan's crippled nuclear complex was more than 10,000 times above normal levels in reactors, the plant operator was quoted by Kyodo news agency as saying on Thursday.

The operator also found radiation in groundwater near a turbine building of the No.1 reactor of the Fukushima Daiichi plant, Kyodo added. And an abnormal level of radioactive caesium has been found in beef from the area, it said. (Reporting by Yoko Nishikawa and Kiyoshi Takenaka,
sourced Reuters)

Friday, March 18, 2011

Chernobyl disaster



The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the Ukrainian SSR (now Ukraine). It is considered the worst nuclear power plant accident in history, and it is the only one classified as a level 7 event on the International Nuclear Event Scale.

The disaster began during a systems test on 26 April 1986 at reactor number four of the Chernobyl plant, which is near the town of Pripyat. There was a sudden power output surge, and when an emergency shutdown was attempted, a more extreme spike in power output occurred, which led to a reactor vessel rupture and a series of explosions. This event exposed the graphite moderator components of the reactor to air, causing them to ignite. The resulting fire sent a plume of radioactive fallout into the atmosphere and over an extensive geographical area, including Pripyat. The plume drifted over large parts of the western Soviet Union, Eastern Europe, Western Europe, and Northern Europe. Large areas in Ukraine, Belarus, and Russia were evacuated, and over 336,000 people were resettled. According to official post-Soviet data, about 60% of the fallout landed in Belarus.

The accident raised concerns about the safety of the Soviet nuclear power industry, as well as nuclear power in general, slowing its expansion for a number of years and forcing the Soviet government to become less secretive about its procedures.

Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl accident. More than fifty deaths are directly attributed to the accident, all among the reactor staff and emergency workers. Estimates of the total number of deaths attributable to the accident vary enormously, from possibly 4,000 to close to a million.[4][5] Despite the accident, Ukraine continued to operate the remaining reactors at Chernobyl until 2000, when the last reactor at the site was closed down.

For more information visit Wikipedia


Brilliant Greenpeace video on Chernobyl


"Chernobyl solution" may be last resort for Japan reactors

Fri Mar 18, 2011 5:01pm IST
By Elaine Lies

Tokyo(Reuters) - A "Chernobyl solution" may be the last resort for dealing with Japan's stricken nuclear plant, but burying it in sand and concrete is a messy fix that might leave part of the country as an off-limits radioactive sore for decades.

Japanese authorities say it is still too early to talk about long-term measures while cooling the plant's six reactors and associated fuel-storage pools, comes first.

"It's just not that easy," Murray Jennex, a professor at San Diego State University in California, said when asked about the so-called Chernobyl option for dealing with damaged reactors, named after the Ukrainian nuclear plant that exploded in 1986.

"They (reactors) are kind of like a coffee maker. If you leave it on the heat, they boil dry and then they crack," he said.

"Putting concrete on that wouldn't help keep your coffee maker safe. But eventually, yes, you could build a concrete shield and be done with it."

Experts say the cores at the six battered reactors at the Fukushima Daiichi power plant, 240 km (150 miles) north of Tokyo, are likely to be safely contained, but worry about the cooling pools for spent fuel, one of which contains plutonium.

So far, authorities have failed to cool the pools, where normally water circulates continuously, keeping racks of spent nuclear fuel rods at a benign temperature.

Helicopters and water cannon trucks have dumped tonnes of water on the reactors, but still the water in the pools is evaporating and the rods are heating up. It is also feared that the quake has smashed the rods into each other, which could cause a nuclear reaction.

"It is not impossible to encase the reactors in concrete, but our priority right now is to try and cool them down first," a Tokyo Electric Power official told a briefing on Friday.

OPEN NUCLEAR WOUND FOR MONTHS

At Chernobyl, an army of workers conscripted by the then Soviet government buried the reactor in tonnes of sand, then threw together a concrete container known as the "sarcophagus" within months of the fire and explosion there.

It failed to set properly and it cracked, leaking radiation into the atmosphere and water. Partly supported by the damaged walls of the reactor building, it has had to be reinforced.

Under a new plan for Chernobyl, a massive structure will be assembled away from the reactor at a cost of billions of dollars, then slid into place over the existing sarcophagus.

Chernobyl-style methods would be even more difficult at Fukushima Daiichi, given the number of reactors involved.

As Japanese officials have said, cooling is still the top priority. Pouring sand onto hot fuel could theoretically produce glass, and that same heat would prevent working on a durable concrete shell.

That means the stricken complex is likely to become an open sore, leaking radioactive particles into the atmosphere, for weeks and possibly months before the Chernobyl solution could even be implemented.

Authorities say radiation outside the Japanese plant is not high enough to cause harm. Still, the 20 km (12 mile) exclusion zone around the plant may end up as a permanent no-man's land, a major problem for small, populous country.

A 30 km (19 mile) exclusion zone remains around Chernobyl.

Tokyo, though, is likely to remain largely unscathed no matter what happens because of its distance from the reactors, no matter how nervous its citizens may be.

It is not accidental that the nuclear plant was built so far away from Japan's biggest city, said Yuki Karakawa, international coordinator at the International Association of Emergency Managers, an extension of the U.S. Federal Emergency Management Agency.

"Those reactors in Fukushima are there for Tokyo's power and Tokyo's benefit, not for Fukushima's," he added. "After all, Tokyo is more than 200 kilometres away."

(Reporting by Elaine Lies; Editing by Mark Bendeich and Daniel Magnowski, Reuters)