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Meltdown Likely Under Way At Japan Nuclear Reactor

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The maximum level is more than eight times the 1,000 micro sievert level to which people can be exposed in one year.

To clarify the above. This is additional exposure based on standards of radiation allowances in radiation environments above the normal exposure by an individual from background and man made radiation.

"Above background levels of radiation exposure, the NRC requires that its licensees limit maximum radiation exposure to individual members of the public to 100 mrem (1mSv) per year, and limit occupational radiation exposure to adults working with radioactive material to 5,000 mrem (50 mSv) per year. NRC regulations and radiation exposure limits are contained in Title 10 of the Code of Federal Regulations, Part 20."

National Regulatory Commission

I'm considered to be an occupational radiation worker and always found it curious that I'm "allowed" more radiation exposure than the general populace. :D

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Thanks Jd..I was already heading in that direction... How do I get the micro symbol on my keyboard?

Edit: Since your previous post gives doses in milliSievert, this is equivalent to 2.4mSv and 8mSv.

The Japanese media seem to be standardly reporting their numbers in micro Sievert... not milli Sievert...

I'm not inclined to start changing the numbers in their articles... That would be bad form. But I can add the equivalent milli reference.

Edited by jfchandler
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Kan giving a live news conference now...

Re Fukushima No. 1 plant... Every possible method has been used to cool down the reactor.

Radiation has spread from these reactors and the reading of the level seems very high.

And there is still a very high risk of further radioactive material coming out...l

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Kan talking about prior 20 Km evacuation area around the Daichi plant...

Now newly advising that people 20 to 30 Km away to remain indoors and not go outside...

I would like to ask the nation...that you act very calmly...

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Cabinet Secretary Edano news conference...

Daiichi No 4 reactor now experiencing a fire...that's one of the reactors that was out of service at time of quake... Used spent fuel rods still inside... Hydrogen generated by heat inside the reactor, and seems to have had explosion there..

Number 4 reactor currently is burning...

We assume that radioactive substances also are being released.

We are making the utmost effort to put out the fire.

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Kan on No. 2 reactor...

A little amount of radioactive substance is assumed to be released to the outside... from the containment pool.

Water injection operations continuing at Reactors 1, 2, 3.. We believe cooling is being effectively done.

As of 10:22 am (Japan time), between reactors no. 2 and 3, 400 milli sievert, and at reactor no. 4 - 100 milli sieverts.

Now we are talking about levels that can impact a human health.

These are readings taken near the area where we believe the release of radioactive materials are happening.

Edited by jfchandler
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In response to reporter question - I've got a report there's a very high probability that the containment vessel was damaged...in Reactor 2.

Decision to advise 20 to 30 Km residents to stay indoors -- and not evacuate -- was made by PM Kan...based on the opinions of the experts.

Re high radioactivity levels, not sure of the source.. could be from No. 4 reactor explosion/fire.

Fire in reactor 4 is in building area... not in reactor itself.

The current high readings we believe are from the Reactor No. 4 fire.

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In Stricken Fuel-Cooling Pools, a Danger for the Longer Term


Published: March 14, Even as workers race to prevent the radioactive cores of the damaged nuclear reactors in Japan from melting down, concerns are growing that nearby pools holding spent fuel rods could pose an even greater danger.


The pools, which sit on the top level of the reactor buildings and keep spent fuel submerged in water, have lost their cooling systems and the Japanese have been unable to take emergency steps because of the multiplying crises.

The threat is that the hot fuel will boil away the cooling water and catch fire, spreading radioactive materials far and wide in dangerous clouds.

The good news is that the Japanese have a relatively long time to deal with the problem. Nuclear experts estimate the timeline for serious problems that could lead to a reactor meltdown as minutes to hours, and put the comparable time for cooling pools at days to weeks.

The bad news is that if efforts to deal with the emergency fail, the results could be worse.

The pools are a worry at the stricken reactors at the Fukushima Daiichi plant because at least two of the three have lost their roofs in explosions, exposing the spent fuel pools to the atmosphere. By contrast, reactors have strong containment vessels that stand a better chance of bottling up radiation from a meltdown of the fuel in the reactor core.

Were the spent fuel rods in the pools to catch fire, nuclear experts say, the high heat would loft the radiation in clouds that would spread the radioactivity.

“It’s worse than a meltdown,” said David A. Lochbaum, a nuclear engineer at the Union of Concerned Scientists who worked as an instructor on the kinds of General Electric reactors used in Japan. “The reactor is inside thick walls, and the spent fuel of Reactors 1 and 3 is out in the open.”


Edited by bkkjames
reduced to "fair use" //Admin
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Please quote articles other than Nation, MCOT, NNT, TAN as fair use

DO NOT quote New York Times, BBC, CNN, ABC, NBC, AP, AFP, REUTERS, FOX and other mainstream media in full.

Thanks for your cooperation


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