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Nuclear events taking place in Japan.

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Dr. Drone

Mon Mar 14 2011, 10:49PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
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Marko

Tue Mar 15 2011, 12:09AM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
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Posts: 3145

According to preliminary news, the unit 2 has just went as well, and workers are evacuating from the plant.

Marko

IamSmooth

Tue Mar 15 2011, 02:31AM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
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If the reactor makes power, how come there is no power to pump the water to cool it? Is it that the lines supplying the power for the pumps are severed?

Marko

Tue Mar 15 2011, 02:36AM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

IamSmooth wrote ...

If the reactor makes power, how come there is no power to pump the water to cool it? Is it that the lines supplying the power for the pumps are severed?

I suspect their pipes and cooling pumps were wiped away by tsunami. They didn't seem to be able to move the water through any of the reactors at all since then, just pour it in and watch it boil (in hopes that vented steam will carry the heat away?). This final explosion is claimed to have been even more epic than the last two, so stay tuned for the videos tomorrow. I also have hard time believing that fuel rods can stay dry for the amounts of time they claim. If out of water I would think they would wrinkle and melt before you can say "OMG the rods are exposed!". The wrinkled mess will still fall into water anyway, so I'd think it's safe as long as there's any water left inside.

By the way, can anyone explain what is the exact purpose of the water-filled torus under the reactor building?

Ash Small

Tue Mar 15 2011, 05:52AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
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Japan's nuclear safety agency said it was unsure if a fresh explosion at its quake-stricken nuclear power plant had damaged one of its reactor containment vessels.

EDIT: Damage to containment vessel confirmed

Radiation in Maebashi, 100 km north of Tokyo, up to 10 times normal levels - Kyodo quoting local govt

Radiation levels in Saitama near Tokyo 40 times normal levels: Kyodo quoting local government

IAEA told Japan spent fuel pond at reactor on fire, radioactivity released into atmosphere

Dose rates of 400mSv per hour at plant.

(Apparently the detection equipment doesn't detect alpha emitters like plutonium and uranium, but only detects the by-products like ceasium, iodine, etc, which are presumably neutron emitters (and/or beta/gamma emitters?))

Marko wrote ...

.By the way, can anyone explain what is the exact purpose of the water-filled torus under the reactor building?

1300169194 3414 FT0 Bwr Mark I Containment Cutaway

Apparently it is a 'Pressure Containment System'

"The BWR is specifically designed to respond to pressure transients, having a "pressure suppression" type of design which vents overpressure using safety relief valves to below the surface of a pool of liquid water within the containment, known as the "wetwell" or "torus". "

And, worst of all for us electronic hobbyists, "Chip prices jump on supply chain disruption: uk.reuters.com"

(Will Japanese exports be radioactive?)

Chris Russell

Tue Mar 15 2011, 09:07AM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

What on earth is going on over there? I would have thought that keeping the spent fuel pond topped off with cool water would have been given just about the highest priority there is. The amount of radioactivity there dwarfs what's in the reactors right now.

Proud Mary

Tue Mar 15 2011, 10:03AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

UPDATE 1-KEY POINTS-Official update on Japan nuclear crisis

TOKYO, March 15 (Reuters) - The following are key points from the latest briefings given on Tuesday by the Japanese government and nuclear power generator Tokyo Electric Power about the nuclear crisis.

* Radiation levels at the quake-stricken Fukushima Daiichi complex have varied wildly, with a reading of 11,930 microsieverts at the main gate of the plant at 0000 GMT, up from 596 microsieverts as of 0630 GMT.

* Elsewhere at the plant, levels reached as high as 400,000 microsieverts an hour (or 400 millisieverts an hour).

* The government gave no update on the status of a steel container surrounding the core of the plant's No.2 reactor, deemed by observers as most at risk of a meltdown.

* An explosion on Tuesday at the No.2 reactor had caused some damage to its suppression pool, which helps to cool and trap the majority of cesium, iodine, strontium in its water.

* Later, there was a fire and explosion at the complex's No. 4 reactor and this is likely to have contributed to rising radiation levels.

* The No. 4 reactor had been shut down for maintenance ahead of the quake, but a spent-fuel cooling pool associated with that reactor caught fire, causing the explosion.

* The No.4 reactor's cooling pool, where spent nuclear fuel is stored, may be boiling and the water level may be falling.

* Radioactivity at the cooling pool is high and Tokyo Electric cannot make checks at the site or determine what has burned.

* Radiation leakage from complex is likely to spread after a fresh explosion at the plant.

(Reporting by Shinichi Saoshiro and Osamu Tsukimori; Editing by Mark Bendeich)

Adam Munich

Tue Mar 15 2011, 11:23AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Well then, I might be needing my KI after all. Those reactors just seem to be getting worse by the day.

pauleddy

Tue Mar 15 2011, 12:01PM

Registered Member #2909 Joined: Wed Jun 09 2010, 12:31AM
Location: fort belvoir, Va USA ( south of DC)
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The sad thing is that because of this disaster, nuclear agentcies in the EU are shutting down some of their older reactors in fear of this happen to there plants. Germany is shutting down all of their pre 1980 plants in till safety revalulation are complete. this should be a lesson for more plants or at least replacing the outdated ones. Here the US there hasn't been a new plant sence the 70's

Ash Small

Tue Mar 15 2011, 12:20PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Radiation levels at the reactor have become too high for normal work in the control room. Workers cannot stay in the room long and so are going in and out alongside monitoring from a different room.-Reuters

Photo taken an hour after the last explosion, showing smoke still rising from the reactor. The authorities have confirmed that the reactor vessel was 'damaged' in the explosion.

--------------------------------

Report from Kyodo on Prime Minister Naoto Kan's anger at TEPCO:

Japan's prime minister was furious with the power firm at the centre of the nuclear crisis for taking so long to inform his office about a blast at a stricken reactor plant, demanding "What the hell is going on?".

"The TV reported an explosion. But nothing was said to the the premier's office for about an hour," a Kyodo reporter quoted Kan telling power company executives.

Kyodo also reports that Naoto Kan ordered TEPCO not to pull employees out of the Fukushima plant.

-----------------------------

The Japanese nuclear safety agency says there are two eight-metre holes in the wall of Fukushima no.4 outer building after the blast there.

Holes in wall mean spent nuclear fuel pool at No.4 reactor is exposed to outside air: TEPCO

Spend Fuel Pools at reactor 5 and 6 are at around 84Â° celisus, according to TEPCO and NHK. Normal temperature is 40

Reactors 4, 5, and 6 were all down for maintenance at time of quake, but all 3 suffered cut-off of water circulation in their spent fuel ponds. The problems at No. 4 are more acute because all of its fuel rods are in the pool while 5-6 have only 1/3 as many fuel rods. But temps slowly rising at 5-6 also.

Kyodo is reporting that TEPCO has become unable to pour water onto the spent fuel in reactor 4.

Failure to keep adequate water levels in a pool would lead to a catastrophic fire, said nuclear experts, some of whom think that unit 1â€™s pool may now be outside.

â€œThat would be like Chernobyl on steroids,â€ said Arnie Gundersen, a nuclear engineer at Fairewinds Associates and a member of the public oversight panel for the Vermont Yankee nuclear plant, which is identical to the Fukushima Daiichi unit 1.

People familiar with the plant said there are seven spent fuel pools at Fukushima Daiichi, many of them densely packed.

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