Naked Science Forum
Non Life Sciences => Technology => Topic started by: Jolly- Joliver on 04/04/2011 15:31:26
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If a reactors material melts down, it is said that it will burn down through the floor of the reactor into the crust.
If you wanted to prevent the material entering the water table by building a containment unit under the ground. What material would be best to use?
Or if you wanted to design a system that would channel that material away from or through the underground water system with out causing contamination, using pipes for example, again what would be the best material to use?
I suppose it would have to be good at preventing radiation release, Like depleted uranium, have and good enought thickness and melting point, that passing material wouldn't melt through it, as it passes down through the crust into the magma.
Any suggestions?
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http://en.wikipedia.org/wiki/Core_Catcher
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http://en.wikipedia.org/wiki/Core_Catcher
Reactor types with core catchers, besides the EPR, are: the "Fast Breeder" SNR-300, VVER-1000/428, SWR1000 and Atmea I
The G.E BWR Mark one reactors at Fukushima do not have that and the core cathers are placed at the point of construction.
Also only two working reactors actually are using them apparently
Thus, in early 2011, the two reactors of the Chinese Tianwan Nuclear Power Plant are the only working nuclear reactors with core catchers.
Why post that? I doubt they will be able to fit one and even if they could they will not be able to with the radiation levels currently present at the plants.
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Thus, in early 2011, the two reactors of the Chinese Tianwan Nuclear Power Plant are the only working nuclear reactors with core catchers.
Why post that? I doubt they will be able to fit one and even if they could they will not be able to with the radiation levels currently present at the plants.
Who said anything about fitting one to a working reactor? Where did that come from?
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Sorry it wasnt letting me post and my last reply disappered
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Sorry it wasnt letting me post and my last reply disappered
OK - so answer my question now please.
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Sorry it wasnt letting me post and my last reply disappered
OK - so answer my question now please.
In the question I posed, I wish bored had said "Ceramic cement" then given the reference he did.
But he just posted a link "Core cather" Which is a device built into the reactor plants. If you were going to use that you would have to fit it. and I spent a while looking at all the reactors that use them and cross referenceing if the Mark one had one blar blar blar. But pofcourse I'm talking about Fukushima, I should have added that to the question, Sorry.
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OK, but there was nothing wrong with BC's post. Despite anything he might have said, I don't think he really is clairvoyant.
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OK, but there was nothing wrong with BC's post. Despite anything he might have said, I don't think he really is clairvoyant.
Hardly has anything to do with being clairvoyant, I have posted lots of threads about Fukushima, and discussed With Mr Chemist on a few of them, hardly a grand leap to see this one related also.
Not to say he did so much post anything wrong, my question was about containment and materials to do so, the link he referenced could relate to either, the containment system itself or the materials it's built with, not listing the material part of that thread, left me looking at the core cather as a device.
So not to say there was anything wrong so much, but he didn't reference what it was about that link he was showing me, leaving me to assume at first, he was recommending using a core cather to stop water contamination, which would not be possible, as they are pre-built into the reactors(leaving new build in the ground-underneath as the only opition).
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Moving on from that and back to the question, if we drilled a hole straight down, through any underground water systems, then used pipes and ceramic Cement, to coat the sides of the hole we drilled(effectivily making a long hollow tube down into the earhts crust), and used it to assist any melted core material on it's journey down to the magma below.
How wide do you think the hole should have to be?
How deep, how far down would we need to drill?
And how thick should the concrete be to coat the inside of the drilled tube-hole?
I assume you could pretty much just drill straight down anywhere near Fukushima, With in reason, a few hundred metres away maybe, then under the reactors construct a funnel or a sloping canal, to chanel the material to the hole. I assume the concrete would need to be thicker for a Canel to work, or atleast be sloped enought so the material doesn't just stop and burn through it and so continues to move.
As a final Question, If you had a canel under the reactors, slanting downwards and material in it, what would be a good, product or material to assists it's decent? I'm not sure if water is, but I am thinking along the lines of flushing.
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"it is said that it will burn down through the floor of the reactor into the crust"
It is also said that it won't.
http://en.wikipedia.org/wiki/China_Syndrome
Perhaps more importantly it has been observed that it doesn't
http://en.wikipedia.org/wiki/Nuclear_meltdown#Meltdowns_that_have_occurred
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"it is said that it will burn down through the floor of the reactor into the crust"
It is also said that it won't.
http://en.wikipedia.org/wiki/China_Syndrome
Perhaps more importantly it has been observed that it doesn't
http://en.wikipedia.org/wiki/Nuclear_meltdown#Meltdowns_that_have_occurred
"it is said that it will burn down through the floor of the reactor into the crust"
It is also said that it won't.
http://en.wikipedia.org/wiki/China_Syndrome
The china syndrome is ofcourse rediculas, if material melted through the floor of a reactor and down into the crust eventually it would join with the magma and stop there it's certainly not going to carry on to the other side of the planet.
And considering that China is next to Japan it's even more silly for the fukushmia situation. It's a nonsense idea. That does not mean that melts downs where material burn into the crust are not possible.
Aljazeera on core melt downs:-
Perhaps more importantly it has been observed that it doesn't
http://en.wikipedia.org/wiki/Nuclear_meltdown#Meltdowns_that_have_occurred
That is not clear either In practice, however, a nuclear meltdown is often part of a larger chain of disasters (although there have been so few meltdowns in the history of nuclear power that there is not a large pool of statistical information from which to draw a credible conclusion as to what "often" happens in such circumstances).[/quote]
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There exist no materials for containing nuclear fuel cores/rods for a longer time. I know USA have tried with different mixtures but none have worked. If we had one we would use it :) It's the combination of hard radiation & heat that destroys them as I understands it. But as BC pointed out, there are some materials that do a better job than others. Still, as it is a really thick slab of reinforced concrete do the job too I think.
"The core catcher ensures the integrity of the containment by long-term stabilisation and cooling of the molten core. The basic principle consists in spreading the melt over a large area of approx. 170 m². Siempelkamp manufactures the spreading area from cast iron elements that for purposes of protection and melt conditioning are covered with special concrete, and have a total weight of approx. 500 Mg."
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Re.
"Aljazeera on core melt downs:-
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an unsupported assertion is made at about 1:08 that a meltdown will occur; it might or it might not.
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Nmbr 4 is what makes me nervous :)
Especially if they are correct in that this pond contain twenty years of spent fuel rods. Wonder how many that would come too?
It's not a good thing storing them in the reactor building, slightly better to store them somewhere else in the nuclear plant. But considering the devastation that wouldn't have helped that much either this time. Interesting stuff BC.
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Re.
"Aljazeera on core melt downs:-
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an unsupported assertion is made at about 1:08 that a meltdown will occur; it might or it might not.
Agree, We really are in un-charted waters, we cannot be fully sure either way. BC are you really a glass half full person?
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Nmbr 4 is what makes me nervous :)
Yeah they had more old rods there then in any of the others but the others still have used rods also. number four was on fire. Potencially the biggest release there. Although number three is plutonium Mox and ruptured.
Three other sites were also having problems, Fukushima Diani 15km south of the Fukushima main plant has had people removed for a 20 km area and apparently another site lost power with the recent 7.4 earth-quake, it was one of the orginal four though, But not so much news is comming out.
Especially if they are correct in that this pond contain twenty years of spent fuel rods. Wonder how many that would come too?
I don't know, apparently in Japan they reprocess the rods, so why they would have sat in the tanks for twenty years I'm not sure unless they were, rods they couldn't be reprocessed anymore.
It's not a good thing storing them in the reactor building, slightly better to store them somewhere else in the nuclear plant.
Completely agree.
But considering the devastation that wouldn't have helped that much either this time.
Completely dis-agree, it's one thing to have old fuel pools that need to be kept with water, it quiet another to have them high up over a functioning reactor which is also having problems and leaking.
The design is stupid, but then three of the people engaged in design process quit in protest over the flaws they saw with the mark one, and that was 35 years ago.
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Saving used fuel rods at a reactor is not a optimal solution. USA does it that way, even though not inside the reactor and it's dangerous. On the other hand they will be dangerous where ever they are, but when a reactor gets a explosive leak you will find the same problem reaching the spent fuel ponds as the radioactivity raise. And it will be hard to find those heroes ready to sacrifice themselves when it becomes real. They seem to trick people into it, now in Japan, offering lots of money to third party personnel sometimes without any family surviving. And it can happen anywhere, for all kinds of reasons, from suicide bombers to natural disaster to human stupidity, nothing excluded.
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Does anyone have a reliable estimate of the reduction in life expectancy of the guys dealing with the emergency?
My suspicion is that they are not at that big a risk.
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Does anyone have a reliable estimate of the reduction in life expectancy of the guys dealing with the emergency?
My suspicion is that they are not at that big a risk.
Looking at chenobyl a lot of the people called in to clean up the disaster died with-in a mounth.
I suppose it depends on the radiation levels they come into contact with, those admitted to hospital from Fukushima were said to have levels 10,000 times normal, so they are probably the most exposed but again decontanmination and drugs might help them to cope better and so survive longer.
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"I suppose it depends on the radiation levels they come into contact with, "
That's what I suppose too. In fact that's why I asked if anyone had any information.
Since radiation doses are cumulative, a day's exposure to 10,000 times "normal" is only the equivalent of a lifetime's normal exposure (very roughly).
Since some people's "normal" is six or more times other people's "normal" it's rather hard to get any real conclusion.
Does anyone have any real data on these people's risk?
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"I suppose it depends on the radiation levels they come into contact with, "
That's what I suppose too. In fact that's why I asked if anyone had any information.
Since radiation doses are cumulative, a day's exposure to 10,000 times "normal" is only the equivalent of a lifetime's normal exposure (very roughly).
Yeah but then those workers had been working to fix the plant for the weeks running up to that day when water went into their boots, so they got 10,000 times exposure for that day, not sure about all the other days leading up to that. They got pulled out a few times because radiation levels were too high for them to work in.
We dont know, and can only make guesses but apparently according one report I saw they were only checking the soil and water and not checking the gas releases they only check the aerosols, According to a french research group. On the big picture Hartman
24 march continuation Big picture
Since some people's "normal" is six or more times other people's "normal" it's rather hard to get any real conclusion.
Does anyone have any real data on these people's risk?
Tepco is ultimately responsible for all the info, The IAEA is the only other group I think has any real access.
I saw this report on Russia Today they drove round near Fukushima and checked the radiation levels
This is the IAEA Report site
http://www.iaea.org/newscenter/news/tsunamiupdate01.html
And this site but it's down for maintence...
http://www.fairewinds.org/
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Wiybit, I keep asking if anyone has any real data on this but, before anyone can answer you keep jumping in and saying that you don't know anything.
I'm not sure that helps.
Does anyone have any real quantitative data about the health risks to the people directly involved in the clean up?
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Wiybit, I keep asking if anyone has any real data on this but, before anyone can answer you keep jumping in and saying that you don't know anything.
I'm not sure that helps.
Does anyone have any real quantitative data about the health risks to the people directly involved in the clean up?
No BC I said the only people that know are The IAEA and Tepco- Tepco are as always not being forth comming.
Hence why I referenced the sites I did the IAEA report site is probably the best place to start, but I doubt even they will tell the whole truth, as they serve the industry.
No one knows that is the reality, it's down to Tepco and the IAEA to inform us.
Fairewinds might be good also, but you think the guy doesnt know what he is talking about.
So basically unless someone from Tepco or IAEA comes on here, I doubt you'll get a better answer.
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"No BC I said the only people that know are The IAEA and Tepco- Tepco are as always not being forth comming. "
Which is why you don't know- like I said.
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"No BC I said the only people that know are The IAEA and Tepco- Tepco are as always not being forth comming. "
Which is why you don't know- like I said.
I said it first, your repeating me, as I said only TEPCO knows.
The IAEA Site http://www.iaea.org/newscenter/news/tsunamiupdate01.html
is probably the best place to look.
But could also go here to TEPCOs information site
http://www.tepco.co.jp/en/nu/fukushima-np/index-e.html
Radiation measurements at Fukushima site from Tepco
http://www.tepco.co.jp/en/nu/fukushima-np/f1/index-e.html
Yet as I said you cannot trust them...
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I saw this today