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Meltdown Likely Under Way At Japan Nuclear Reactor


george

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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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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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Kan

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

By WILLIAM J. BROAD and HIROKO TABUCHI

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.

Multimedia

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.”

http://www.nytimes.c...ner=rss&emc=rss

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, FOX and other mainstream media in full.

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

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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, FOX and other mainstream media in full.

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

You can quote from any source as "fair use" quote - the mentioned local sources can be quoted in full.

up to 200 words or 2 paragraphs.

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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, FOX and other mainstream media in full.

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

It means other then the 4 sources above that allow full quotes of articles, any others you can only use one or two paragraphs (sentences if the full article is only one-two paragraphs) (fair use) and link to article.

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Japanese media now discussing the sudden elevation of radiation readings at the plant to milli sieverts... 1000 times higher than the prior numbers of micro sieverts...

Kan says readings at the reactors ranged between 100 and 400 milli sieverts...

Equivalent amounts:

Increase in lifetime dose to most heavily exposed people living near Chernobyl 430

Causes radiation sickness (when absorbed in a short period) >1,000

Dose from a single full-body computed tomography (CT) scan 45

When delivered in a single dose, increases the risk of developing cancer by 1% 100

Average dose to person living within 10 miles of Three-Mile Island (TMI) caused by the accident of 28 March 1979 0.08

Most heavily exposed person (a fisherman) near TMI <1.0

Source:

http://users.rcn.com.../Radiation.html

Edited by jfchandler
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Japan Prime Minister Naoto Kan delivered a message to the nation at 11.15h,

and ask residents around 20km to 30km from the Fukushima Daiichi nuclear plant,

to stay home and to avoid possible radiation.

translated : www.asahi.com Mar 15, 2011 at 11.21h Japan time

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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, FOX and other mainstream media in full.

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

It means other then the 4 sources above that allow full quotes of articles, any others you can only use one or two paragraphs (sentences if the full article is only one-two paragraphs) (fair use) and link to article.

ok cheers

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I was advised the other day that, if appropriate, it was OK to full quote the Japanese media reports...

Please quote articles other than Nation, MCOT, NNT, TAN as fair use

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

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

You can quote from any source as "fair use" quote - the mentioned local sources can be quoted in full.

up to 200 words or 3 paragraphs.

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so they keep spent fuel rods in water tanks on top of the containment structures? Sounds odd. I pictured spent fuel rods were normally kept at ground level water basins.

Imagine if one or more of China's or Korea's many nuclear facilities were breached - prevailing winds (west to east) would likely carry the radioactivity over Japan. Similarly, if one of the proposed Thai N plants were to leak, the radiation would likely go in the direction of Cambodia, Laos, Vietnam, Brunei, Malaysia, and possibly Philippines and southern China, HK and Taiwan. Who says it couldn't happen? Just a month ago, nuclear experts would have told you that Japanese N plants were among the safest in the world - virtually fail-safe. Would anyone familiar with Thai safety & security standards expect Thai N plants to be near as safe as Japanese plants? About once a month, an armory blows up or a bunch of weapons & ammo gets stolen from a Thai military facility. The same military that would be charged with providing security for a Thai N plant.

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just a better understanding and a better support, could I still pulling translated news line from Japanese www.asahi.com ?

Please quote articles other than Nation, MCOT, NNT, TAN as fair use

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

Thanks for your cooperation

//Admin

Sorry just to understand, we can only quote local news sources?

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The next thing to consider here...is what will be the dispersion of those high levels of radiation at the plant...

If 400 milli sievert at the plant... what's it going to be in the miles spreading out from the plant...

And if the prior radiation could impact, at low levels, the USS Ronald Reagan sailing far off the coast, what's the latest emissions going to do?

No word yet on any readings in surrounding areas of the plant.. I haven't seen anything even saying if they have any nearby monitoring stations -- other than the pre-established ones at the boundary of the plant.

By the way, for background, there are SIX total reactors at the Daiichi Plant... -- 3 that were operating at the time of the quake, and 3 that were "down" for scheduled maintainance...

The problems up until today were all at the active reactors 1 to 3... Now that's spread with the fire to the No. 4 reactor...which wasn't generating power....

There's still the No. 5 and 6 reactors at the Daichi Plant, plus four other reactors at the Daini Plant 10 Km away that also are having lesser cooling problems.

I hate to be a pessimist... but... since the start of this.. nothing good has been happening with the reactor situation... It's all been a slow downward spiral... :ph34r:

Edited by jfchandler
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I am pretty sure that fair use means that you can quote 3 paragraphs and then provide a link to the rest of the article.

Fair use allows you to quote *part* of a work (and not a substantial part) for the purposes of criticism, study etc. Copying material for the purpose of 'republishing news' is not fair use. Attribution should be given.

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