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 Post subject: Fukushima fuel pools
PostPosted: Sep 16, 2013 3:54 pm 
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They're talking possible catastrophe at Fukushima again, how likely is the worst case scenario of the spent fuel being exposed and fire occurring and how much of the globe would be affected by this?

http://www.washingtonsblog.com/2012/04/ ... shima.html

Quote:
Japan’s former Ambassador to Switzerland, Mr. Mitsuhei Murata, was invited to speak at the Public Hearing of the Budgetary Committee of the House of Councilors on March 22, 2012, on the Fukushima nuclear power plants accident. Before the Committee, Ambassador Murata strongly stated that if the crippled building of reactor unit 4—with 1,535 fuel rods in the spent fuel pool 100 feet (30 meters) above the ground—collapses, not only will it cause a shutdown of all six reactors but will also affect the common spent fuel pool containing 6,375 fuel rods, located some 50 meters from reactor 4. In both cases the radioactive rods are not protected by a containment vessel; dangerously, they are open to the air. This would certainly cause a global catastrophe like we have never before experienced. He stressed that the responsibility of Japan to the rest of the world is immeasurable. Such a catastrophe would affect us all for centuries. Ambassador Murata informed us that the total numbers of the spent fuel rods at the Fukushima Daiichi site excluding the rods in the pressure vessel is 11,421 (396+615+566+1,535+994+940+6375).


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 4:36 pm 
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Well they certainly have a lot of fission products in them.

But all the really hot stuff is gone so it would just be a massive Strontium-Caesium contamination.

I have my doubts if they would actually get hot enough for the Zirconium to catch fire.....
Are the pools recessed into the ground or entirely above grade? If the former then the fire brigade could concievably prevent them getting enormously hot just by hosing the pile of rubble down continuously.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 4:51 pm 
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Washington's Blog? Washington's Clueless, clearly.

It is not "dangerously, open to air". It is "fortunately, open to air so that air cooling can prevent fuel meltdown".

It would take months to boil off all of the common spent fuel pool water. Even without water, air cooling suffices, even with tightly placed fuel assemblies as the water rods act like air cooling channels to passively convect the heat out.

Old spent fuel is not a problem. The problem is morons who can't do basic thermal calculations and believe everything their own ignorant minds allow them. Grown men and women with an overactive imagination, lean on science, fat on hyperbole, who cannot think for themselves. A sad bunch, and they come by the dozen.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 5:10 pm 
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Joined: May 15, 2011 12:06 am
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I just read a few paragraphs of this article. Good grief. We are in a PR war, and articles like this one are re-awakening all the old irrational fears about nuclear power. Whether the authors are just ignorant or are deliberately trying to deceive, I don't know. But I do know that advocates of nuclear power need to go aggressively on the offensive to counter this sort of hysteria. Exactly how that can be done I don't know, but we should all try to do something. Don't assume that the general public is getting both sides of the story.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 6:10 pm 
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It's hard to know what to believe if you lack the background to get past all the "facts" and predictions.

It didn't really feel very plausible to me and some of the sources seem a little strange like the former Japanese ambassador to Switzerland.

What I do know is that it's still not possible to accurately predict earthquakes, which is how the piece starts.

I also don't understand the mechanism where this scenario they claim is a looming danger would bring about global destruction of not just human civilization but the biosphere as well. Certainly there would be serious local impacts if in fact it was possible to get the spent fuel to burn as they claim and winds could carry that quite far, but they tend to the east in that region meaning most of the material would go into the Pacific, which would dilute it over time.

Quote:
Many of our readers might find it difficult to appreciate the actual meaning of the figure, yet we can grasp what 85 times more Cesium-137 than the Chernobyl would mean. It would destroy the world environment and our civilization. This is not rocket science, nor does it connect to the pugilistic debate over nuclear power plants. This is an issue of human survival.


This also seems really silly to me.

Quote:
Anti-nuclear physician Dr. Helen Caldicott says that if fuel pool 4 collapses, she will evacuate her family from Boston and move them to the Southern Hemisphere. This is an especially dramatic statement given that the West Coast is much more directly in the path of Fukushima radiation than the East Coast.


I tried reading one of her books to just get an idea of some of the concerns that people have about nuclear power and it made no sense to me at all. I get the impression that many people have this concept of living in a pristine environment in regards to radiation and that we have no natural protection against exposure. The more I learn about radiation and the biological response to it by organisms across the spectrum, the more I question the sanity of people who think that nuclear power is going to destroy the globe.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 6:27 pm 
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Joined: May 15, 2011 12:06 am
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Doug, if Helen Caldicott is mentioned as a serious source, you can be sure that the article is bunk.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 6:42 pm 
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Joined: Nov 30, 2006 9:18 pm
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Location: Montreal
Russ wrote:
Doug, if Helen Caldicott is mentioned as a serious source, you can be sure that the article is bunk.

Bingo!

https://www.facebook.com/photo.php?fbid ... nt_count=1


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 6:48 pm 
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Location: Montreal
FD unit 4 SNF pool heat source:


Attachments:
FD_SNFP4_heat.JPG
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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 7:01 pm 
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Russ wrote:
Doug, if Helen Caldicott is mentioned as a serious source, you can be sure that the article is bunk.


I had no idea, I guess that's why they had her at the end of the piece, many people probably won't get that far.

http://www.theguardian.com/environment/ ... te-beliefs

Quote:
My request to Helen Caldicott was a simple one: I asked her to give me sources for the claims she had made about the effects of radiation. Helen had made a number of startling statements during a television debate, and I wanted to know whether or not they were correct. Scientific claims are only as good as their sources.

Here are three examples of the questions I asked, and the answers she gave me.


She then goes on to completely contradict herself and brings up some weird conspiracy theory. Her books don't belong on the shelves of the library I think.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 7:49 pm 
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Joined: Aug 29, 2008 4:55 pm
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Location: Idaho Falls, Idaho
sounds like the Japanese political talk has to be pretty dramatic in order to get them to dedicate the funds for clean-up.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 8:10 pm 
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How Many People Have Really Been Killed by Chernobyl?

http://www.slate.com/articles/health_an ... ation.html


not that many... anyone else want to guestimate?


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 8:29 pm 
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Joined: Jul 28, 2008 10:44 pm
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jaro wrote:
FD unit 4 SNF pool heat source:


So we have a tonne of material generating 4kW of power.
Probably we should tie it to the surface area and compare the power density to a incandescent light bulb.

Here goes - sanity check please as this seems incredibly low
BWR fuel rod data from http://www.nucleartourist.com/basics/hlwaste.htm
rod height 3.8 m, diameter 1.25cm
UO2 mass in a fuel assembly 208kg, 63 rods/assembly.
=> 3.3kg/fuel rod.
4kW/tonne => 4W/kg =>13W/fuel rod.

Surface area = 3800cm * pi * 1.25cm

Surface area of a light bulb 120cm^2 http://www.chacha.com/question/what-is- ... light-bulb

So very roughly this has the power density of a 0.1W light bulb. You will need to pack an awful lot of these guys together and insulate them well in order to get them to raise the temperature much at all.

A typical night light is 3-7 Watts and has a smaller surface area than a standard light bulb. This seems like worrying that a night light is going to start a fire and burn your house down.

[Edited per correction below]


Last edited by Lars on Sep 16, 2013 11:56 pm, edited 1 time in total.

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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 16, 2013 10:10 pm 
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Joined: Jun 19, 2013 11:49 am
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Remember that that 4kW/t figure is for the fuel material itself

Not for the assembly, so its only 208kg, not 320kg of material per assembly.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 17, 2013 1:22 am 
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Joined: Jul 14, 2008 3:12 pm
Posts: 5048
jaro wrote:
FD unit 4 SNF pool heat source:


To put that in perspective: 4 kW/ton is similar to the the power density of a human working out. It's funny you don't see humans melting down in the gym into a puddle of magma.


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 Post subject: Re: Fukushima fuel pools
PostPosted: Sep 17, 2013 1:48 am 
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Joined: May 15, 2011 12:06 am
Posts: 225
Cyril R wrote:
To put that in perspective: 4 kW/ton is similar to the the power density of a human working out. It's funny you don't see humans melting down in the gym into a puddle of magma.


I came pretty close once. :lol:


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