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Meltdown Likely Under Way At Japan Nuclear Reactor


george

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Lets recall the progress since it started.

TEPCO managed to delay an ignition till now or maybe tomorrow but was unable to successfully cool the fuel rods.

Even they succeed, the rods need to be secured. How are they going to do that? Robots? How about reachability when robots are used? Transport? - It's just such a complex problem that's not easy to handle.

I still hope though, but fear the worst.

Edited by elcent
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Not to be outdone by the U.S. and the other countries who followed the U.S.'s lead at 80 Km...

Singapore evacuating citizens within 100 km of Fukushima plant

SINGAPORE, March 17, Kyodo

The Singapore government on Thursday advised its citizens to evacuate areas which are within 100 kilometers of the stricken nuclear power plant in Japan's northeast.

''The Singapore Embassy in Tokyo has made arrangements for Singaporeans living within the radius of 80 to 100 km from the nuclear power plant to leave for safer locations today,'' the Foreign Ministry said in a statement.

It advised Singaporeans to evacuate Fukushima and Miyagi prefectures with immediate effect.

It also urged Singaporeans in the Kanto region that includes Tokyo, Chiba, Kanagawa and Saitama prefectures to leave the area if they have no pressing reasons to remain, the statement said.

The Singapore Embassy in Tokyo has been assisting Singaporeans who are leaving Japan with travel arrangements.

The government is also considering the possibility of Singapore Airlines mounting extra flights for this purpose.

http://english.kyodo...1/03/79013.html

Edited by jfchandler
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NHK: these numbers are all micro-sievert...the smaller number...not the larger milli-sievert.

Higher radiation levels continue around Fukushima

Radiation levels at municipalities around the quake-damaged nuclear power plant in Fukushima Prefecture continue to be higher than normal. But authorities say the detected levels pose no harm to human health.

As of 9 AM Thursday, at Fukushima City, 65 kilometers northwest of the Fukushima Daiichi plant, radiation level was 13.9 microsieverts per hour. This is more than 340 times the usual background level.

At Koriyama City located west of the plant, the reading was 2.71 microseiverts, 45 times the normal level.

South of the plant, in Iwaki City, radiation levels were as high as 20 times the usual level at 1.25 microseiverts.

At the Onagawa nuclear power plant 120 kilometers northeast of the Fukushima plant, radiation levels measured 3.2 microseiverts, 32 times the usual amount.

In Kitaibaraki City south of the Fukushima plant, radiation found to be 1.19 microseiverts, 23 times the normal figure.

But health authorities say one-hour of exposure to radiation at any of the observed levels would range between one 500th to one 40th of the amount of radiation the body would receive in a single stomach X-ray.

Thursday, March 17, 2011 13:57 +0900 (JST)

http://www3.nhk.or.j...lish/17_26.html

Edited by jfchandler
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The High Price of Merkel's Nuclear About-Face

Chancellor Angela Merkel's decision to temporarily shut down seven nuclear reactors could cost the industry more than a half-billion euros and result in Germany not meeting its CO2 emission reduction goals. The rest of the world is taking a wait-and-see approach.

http://www.spiegel.de/international/germany/0,1518,751245,00.html

In meanwhile the nuclear lobby in Germany sued the govt ...

Edited by elcent
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Surprise, surprise...

NHK:

Japan shelves plan to build 2 nuclear power plants

Japanese nuclear power plant operators have shelved plans to build 2 plants in northern Japan, in light of the nuclear crisis unfolding at the Fukushima Daiichi plant.

On Thursday, Tokyo Electric Power Company, which was due to start building one plant in Aomori Prefecture next month, has notified the local government of its decision.

The No. 1 reactor of the plant was expected to go online in 6 years, with a projected capability of 1,380 megawatts, making it the most powerful in Japan.

Another plant operator, Electric Power Development, said it has put on hold the 3-year-old construction of a plant, also in Aomori.

That would have been the first in Japan to burn a mixture of uranium and plutonium extracted from spent fuel. The target year for its completion is 2014.

Thursday, March 17, 2011 20:20 +0900 (JST)

http://www3.nhk.or.j...lish/17_36.html

Edited by jfchandler
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and more from http://www.noagendareport.com/?p=1593

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some good some bad news. Just wonder how they can connect the electricity to the cooling system when it's damaged. It's almost impossible at this stage. Maybe just for the waqter pumps.

(All times are local in Japan GMT+9)

  • Timestamp: 10:20pm The head of the UN's atomic watchdog has said he wants to visit the troubled nuclear plant, saying the situation there "continues to be very serious".
    Yukiya Amano is on his way to Tokyo with a small group of nuclear inspectors from the International Atomic Energy Agency.
  • Timestamp: 10:10pm Andrew Thomas, our correspondent in Tokyo, just tweeted:

    Two big aftershocks in the space of the last half hour - and both close to the original 'Big One's' epicentre

  • Timestamp: 10:00pm The operator of the Fukushima Daiichi power plant has said that electricity could be connected to the plant on Thursday, the Reuters news agency has reported.
    Tokyo Electric Power Co has said it hopes to connect outside power cables to two of the plant's six reactor units in a bid to restart cooling pumps knocked out last Friday.

Aljazeera Edited by elcent
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Maybe I've been listening and watching NHK for too long today...

They're airing a piece on how to treat hypothermia in the elderly...

And the expert they're interviewing advises... "The first step is to warm them up..."

DUHHHH!!!! :blink:

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this is may be a super good news - electricity may be rstored tomorrow and the primary pum will be resumed !

there are 320 workers working on site and reconnecting the power supply to the primary pump. this may take 10 to 15 hours. once power resumed, will pump water into reactor 2, 3 and 4.

福島第一の電源、18日復旧か 冷却装置稼働の可能性も

translated : www.asahi.com Mar 17, 2011 at 22.05h JST

Edited by ETatBKK
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this is may be a super good news - electricity may be rstored tomorrow and the primary pum will be resumed !

there are 320 workers working on site and reconnecting the power supply to the primary pump. this may take 10 to 15 hours. once power resumed, will pump water into reactor 2, 3 and 4.

福島第一の電源、18日復旧か 冷却装置稼働の可能性も

translated : www.asahi.com Mar 17, 2011 at 22.05h JST

that's maybe too late for unit 2, 3 and 4

unit 1, 5 and 6 maybe saved then.

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Translation: It might be a nuclear bomb.

That's according to several definitions of nuclear criticality that I looked up. But I do find it hard to believe anyone would be quite so stupid as to put enough fissionable stuff that close together. So, someone tell me this is wrong. Please?

What is missing here is the 'sudden pressure' component of a bomb.If the containment vessel steams up and breaches it still won't be the same as compressing a ball of uranium or plutonium with a perfectly calibrated surrounding high explosive charge detonated at the exact right sequence that causes it to evenly reduce it's size by orders of magnitude until it must re-expand in a super critical state.

It won't be a nuclear bomb, but it might be a sort of 'dirty bomb' with high heat popping out highly radioactive stuff, like an oversized roman candle. Reminds me of my 'flower power' days in Wash.D.C. in the 60's. There was a 'Weather Underground' type alternative tabloid called DC Free Press. One issue had simple cut-away drawing of the inside workings of an H bomb, with explanations. Plastic explosives are needed to instantly compress the Atom bomb which, within less than a millisecond - provides enough heat and pressure to trigger the Hydrogen. I can picture the design now as clearly as the day I saw it, but I don't think I'll draw it out here for T.Visa.

Incidentally, I think if there's a full meltdown, the nuclear mess will burn down a ways, but I can't picture it going down anywhere near as far as the molten iron core of the planet. I think that's a dramatization we can put in the same category as the Loch Ness monster or Big Foot or crop circles.

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a 50% good news, better than 100% bad news ! hope and pray for the best !

this is may be a super good news - electricity may be rstored tomorrow and the primary pum will be resumed !

there are 320 workers working on site and reconnecting the power supply to the primary pump. this may take 10 to 15 hours. once power resumed, will pump water into reactor 2, 3 and 4.

福島第一の電源、18日復旧か 冷却装置稼働の可能性も

translated : www.asahi.com Mar 17, 2011 at 22.05h JST

that's maybe too late for unit 2, 3 and 4

unit 1, 5 and 6 maybe saved then.

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after helicopter water dump, radiation level has no major change.

measuring 500m northwest from the reactor building, after the helicopter water dump radiation level at reactor 3 at 13.30h was 4.2 mSv per hour, then at 14.00h was 4.0 mSv.

when Seld Defense Force water cannon spread water from 15.50h to 20.10h, the radiation level stablised at 3.7 to 3.6 mSv per hour.

ヘリ放水後の放射線量、大きな変化なし 福島第一原発

translated : www.asahi.com Mar 17, 2011 at 22.39h JST

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(All times are local in Japan GMT+9)

  • Timestamp: 11:00pm More on the move by Tokyo Electric Power Co (Tepco) to install outside electricity at the damaged nuclear facility to restore power to the cooling pumps.
    According to news reports in Japan, Thursday's attempt to set up power cables were unsuccessful, delaying the move until Friday. The reasons why are not clear.
    It is likely that trucks and heliopters will also be used again to dump water on the reactors in an attempt to cool them down.

- aljazeera
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Just be aware, it's not just a matter of connecting a working AC feed...

The existing pumps in the reactors were trashed by the tsunami...

As best as I understand it, TEPCO will either need to repair those or replace them... And I haven't heard anything about their intended approach to that...

And whatever work they're going to be doing on the pumps, it's going to be in a radiation exposure environment.

They, supposedly, didn't make as much as expected progress on the AC today because the water spraying didn't happen until late in the afternoon/evening.

Edited by jfchandler
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Scandal-ridden energy company behind Japan's nuke crisis

(AP) TOKYO - Behind Japan's escalating nuclear crisis sits a scandal-ridden energy industry in a comfy relationship with government regulators often willing to overlook safety lapses.

Leaks of radioactive steam and workers contaminated with radiation are just part of the disturbing catalog of accidents that have occurred over the years and been belatedly reported to the public, if at all.

In one case, workers hand-mixed uranium in stainless steel buckets, instead of processing by machine, so the fuel could be reused, exposing hundreds of workers to radiation. Two later died.

"Everything is a secret," said Kei Sugaoka, a former nuclear power plant engineer in Japan who now lives in California. "There's not enough transparency in the industry."

Full Story.

CBS News-- 2011--03--17

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7322952df8e2abb4c33dd8ed44f883f7.jpg8ecd333e0f919dc1bb3fb4a92a80fed6.jpg

I can see this concept for a quick rebuilding. It only takes six month to construct and can be used for appartments, schools and whatsoever. It can be on land or water.

A special foil is used instead of glass which is even more robust.

The foil is made of ethylene tetrafluoroethylene (ETFE), is lighter, stronger and more durable than glass, and is self-cleaning and recyclable

A very energy efficient design. Wind, solar and thermal energy can be stored in the basement for up to six months and turned into electricity.

This is the time now. Russian Architects, German teams and probably Japanese to realize this concept.

more of the same here

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(All times are local in Japan GMT+9)

  • Timestamp: 11:28pm BBC film-maker Adam Curtis has posted a worrying blog about boiling water reactors, the design used at Fukushima Daiichi.
    According to a documentary he made previously, the potential dangers of these models - namely in the cooling systems - were known about decades ago
    You can watch the film here.

aljazeera
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"The possibility of re-criticality is not zero".

can somone translate that? Although I'm aware that there are many wordgames, this one is the top I guess.

Further to earlier answers.

The critical mass of uranium-235 is 50kg (as a sphere of pure metal). If you have this much uranium 235 in one place, it will go critical (ie. start a nuclear chain reaction) and will generate a massive amount of heat and radiation (much more than we are seeing now at Fukushima). One way of designing a nuclear bomb is to get two hemispheres of pure uranium-235 of say 40kg each (below the critical mass), and then put them together (such that you now have an 80kg sphere). That is now super-critical, and will cause a nuclear explosion. Note that criticality does not necessarily lead to a nuclear explosion - the reactors in normal operation run at criticality but they dont explode. The criticality is controlled (so-called delayed criticality), the radiation is contained and the heat is taken out (and used to generate electricity).

Now within both the reactors and the fuel ponds of Fukushima, I am sure there is very much more than 50kg of uranium-235. I dont know the exact figure but it will be many tonnes, maybe hundreds of tons altogether. So in theory then, there is easily enough material to create criticality. In theory. But it is not pure (far from it), and it is not (at the moment) in one place. And neutron absorbers are also in place to prevent criticality. Whilst it stays that way, it will remain sub-critical.

So the risk is then that the cooling water evaporates, the heat then rises rapidly, and everything melts. In this scenario, the geometry of the environment becomes important. In the ponds, if the fuel rods do melt one would imagine they are likely to form a flat layer at the bottom of the pool, which means that most of the emitted neutrons will go out of the layer (either upwards or downwards), and hence not collide with other uranium-235 atoms. This geometry is much less likely to go critical than a sphere. With regards to the reactors, modern reactors are designed such that even with a melt down the geometry is such that it should not go critical even with a full fuel load.

Next then, what would happen if it did by chance go critical? It doesn't necessarily lead to a supercritical state and a nuclear explosion. More likely is some sort of thermal explosion or melt down, that disperses the uranium-235 prior to any nuclear explosion. The Chernobyl reactor went critical (some say, super critical) but exploded (ie a thermal explosion of the reactor caused by gas/steam pressure) prior to any nuclear explosion occurring, thereby dispersing the fuel. Only 3 examples of reactors reaching this uncontrolled critical state (so-called prompt critical) have been recorded and all 3 resulted in thermal explosions.

You might well say that Chernobyl was pretty horrendous, and it was. But it would have been a lot worse if the explosion has been a nuclear one.

To summarise then (1) the circumstances don't really favour criticality and (2) in the unlikely event of criticality, a thermal blast or melt down is much more likely than a nuclear explosion.

The statement was just saying that there remains a finite chance (albeit small, I suspect they dont really know how small) of criticality occurring either in the reactors or the pools, leading to significantly higher levels of heat and radiation compared to the sub-critical condition (in other words, than beforehand).

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This is a very interesting link -

Comparing Chernobyl & Fukushima

http://www.japanprobe.com/2011/03/17/comparing-chernobyl-fukushima/

Good article.

Many major differences are noted in the article, and also a couple of major differences not mentioned. Notably that (a) the chernobyl reactor had a positive void coefficient, which meant that when water turned to steam, the reaction increased, and ( b ) the graphite tips of the control rods actually made the reaction increase further (graphite being a moderator) as the control rods were (partially) inserted when the reactor was scrammed.

My understanding of the fukushima reactors is that they do not have either of these design flaws.

Edited by JulianLS
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