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Thread: The Japanese Nuclear situation

  1. #1 The Japanese Nuclear situation 
    Forum Professor leohopkins's Avatar
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    They test nuclear bombs underground and the radiation gets contained.
    Why do they not build nuclear power stations deep underground? - If it meltsdown and explodes the radiation will be contained?

    Further to this.....

    Please do correct me if I am wrong but the fuel rods are not rich enough for a nuclear explosion...the fission happens a lot more "slowly" but creates heat; its the heat the boils the water and in turn the steam power turns a turbine which creates electricity.

    They are trying to cool it down because otherwise if it gets that hot the containment vessels may explode as they will not be able to cope with the pressure of the steam / gas due to the expansion due to the heat. (Chernobyl was a steam explosion)

    BUT.....the resultant explosion sprays radioactive material outward for many miles.

    So......instead of trying to cool it with water all the time. Why do they not pump everything out so the fission material remains in a vacuum.....getting rid of any possibility of explosion due to the gas/water/steam etc. Why is this not a viable option?

    Id like to know your thoughts as I am directly affected by this disaster. My 4 year old son is stuck in Japan with my wife.

    Thanks;
    Leo


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  3. #2 Re: The Japanese Nuclear situation 
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    Quote Originally Posted by leohopkins
    They test nuclear bombs underground and the radiation gets contained.
    Why do they not build nuclear power stations deep underground? - If it meltsdown and explodes the radiation will be contained?
    You could build it underground, but it wouldn't do that much good. The radioactive fission products will decay, there's nothing stopping that. So the heat has to be removed. If you confine it underground, without cooling it, the steam pressure would keep building up until it made its way to the surface. Or, if there was no water to make steam, the fuel keeps getting hotter and burns its way through its container and gets into the ground water.
    Further to this.....

    Please do correct me if I am wrong but the fuel rods are not rich enough for a nuclear explosion...the fission happens a lot more "slowly" but creates heat; its the heat the boils the water and in turn the steam power turns a turbine which creates electricity.

    They are trying to cool it down because otherwise if it gets that hot the containment vessels may explode as they will not be able to cope with the pressure of the steam / gas due to the expansion due to the heat. (Chernobyl was a steam explosion)

    BUT.....the resultant explosion sprays radioactive material outward for many miles.

    So......instead of trying to cool it with water all the time. Why do they not pump everything out so the fission material remains in a vacuum.....getting rid of any possibility of explosion due to the gas/water/steam etc. Why is this not a viable option?

    Id like to know your thoughts as I am directly affected by this disaster. My 4 year old son is stuck in Japan with my wife.

    Thanks;
    Leo
    The containment vessel won't explode. This is different than Chernobyl, because Chernobyl happened with the reactor critical (a nuclear chain reaction was going on). This made a lot more heat faster, to create the steam explosion. Then in addition to that it had graphite moderator which caught fire. This fire contributed to spewing the radioactive material into the air.

    The Fukushima reactors have the nuclear chain reaction shut down. This means there is only the decay heat caused by decay of the fission products. Decay heat is around 7 % of full power right after the reactor is shut down, and decreases exponentially thereafter. So what you have is a slow release of heat and the temperature builds up gradually. If the containment fails, it will probably just be a crack that lets some of the radioactive material slowly escape.

    Your idea of keeping it in a vacuum is no good. With no way of releasing the heat, it would melt any kind of container it is in.


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  4. #3  
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    You'll notice they're all built adjcent to a large body of water...for cooling. If they were underground, it would be under the water table and need to constantly be pumped dry.
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  5. #4  
    Forum Freshman AlphaParticle's Avatar
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    How exactly does Radiation effect the human body??? (keep in mind i'm 14)
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  6. #5  
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    Quote Originally Posted by AlphaParticle
    How exactly does Radiation effect the human body??? (keep in mind i'm 14)
    This explains it pretty well.
    http://www.hss.energy.gov/HealthSafe...intro_9_5.html
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  7. #6  
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    Quote Originally Posted by AlphaParticle
    How exactly does Radiation effect the human body??? (keep in mind i'm 14)
    1) It depends on the dose. A dose of about 3-10 mSv, as in a typical X-ray exam, has negligible effect. The mSv stand for the unit of dose--millisevier. The dose of one Sv (which is 1000 times larger than one mSv) would be dangerous. About 50% of experimental rats would be killed, within a day or two, after receiving a dose of 6 Sv.

    2) Does anyone know how many mSv is received per day by general population in Japan, for example, at 10 miles or 100 mi away from the damaged reactors? That would help me to figure out what the situation is. Speaking about dangers without numbers is not very useful.

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  8. #7  
    Forum Freshman AlphaParticle's Avatar
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    Thanks for the website. To some it up, basically, the radiation messes with, and destroys bonds within protein molecules, therefore changing their chemical properties and altering their purpose! (am i right?)
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  9. #8  
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    One thing that definitely is not clear to me is why exactly didn't the Japanese take any safety measures before? They're located in a geologically dangerous area, and they should have seen huge Earthquakes coming anytime... I wonder why they do not have extra cooling systems in the stations. They reported that in one of the stations the cooling system isn't working so now they're watering it with helicopters REALLY? If they only had an extra cooling system, at least a portion of these disasters would not have happened I'm so sorry for the people that have to suffer because of this now...
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  10. #9  
    Veracity Vigilante inow's Avatar
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    They had back-ups, back-ups for those back-ups, and other systems in place to do exactly what you said. The challenge was that, after the earthquake, the tsunami wiped out power to the back-up systems. Those were backed up with batteries, but those could only last for so long. Once the batteries died, that's when things needed to be done differently.

    To suggest that the Japanese didn't plan or were foolish is misinformed and naive.
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  11. #10  
    Forum Freshman BlueBook's Avatar
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    Quote Originally Posted by inow
    They had back-ups, back-ups for those back-ups, and other systems in place to do exactly what you said. The challenge was that, after the earthquake, the tsunami wiped out power to the back-up systems. Those were backed up with batteries, but those could only last for so long. Once the batteries died, that's when things needed to be done differently.

    To suggest that the Japanese didn't plan or were foolish is misinformed and naive.
    You're right, I could be misinformed, but I never suggested that they were foolish. I made conclusions from the information that I had, and I am genuinely sorry if that was wrong of me to do so... And btw thank you for sharing that with me, but are you sure that they had an extra cooling system?
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  12. #11  
    Forum Radioactive Isotope MagiMaster's Avatar
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    Not to mention that this wasn't just a huge earthquake. This was a 9.0 and the system was designed with up to an 8.5 (IIRC) in mind. Remember that earthquakes are measured on a logarithmic scale, so a 9.0 is over 3 times that powerful and is something that only happens once every 20 years over the whole world.

    Plus, as inow mentioned, the reactors actually survived the earthquake very well. It was shortly after that that the tsunami flooded everything and knocked out the power and the generator backup. Plus, the reactors themselves, while several have been essentially destroyed, aren't the source of the radiation problems. (That's from the waste stockpiles.) Overall, I'd say they've done extremely well.

    (Crossposted)
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  13. #12  
    Veracity Vigilante inow's Avatar
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    Quote Originally Posted by BlueBook
    are you sure that they had an extra cooling system?
    Wait, what? Who said that?
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  14. #13  
    Forum Freshman BlueBook's Avatar
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    Quote Originally Posted by inow
    Quote Originally Posted by BlueBook
    are you sure that they had an extra cooling system?
    Wait, what? Who said that?
    Calm down there partner, I'm not starting an argument here. You said they had backups for exactly what I said. And I said that it would've been good if they had an extra cooling system that would run on any emergency...
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  15. #14  
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    I said they had back-ups and redundancies and back-ups for those... not extra cooling systems. ... Partner.

    I'm not arguing. I'm making sure you read me correctly, and don't misrepresent my position when responding. Partner.
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  16. #15  
    Forum Freshman BlueBook's Avatar
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    Quote Originally Posted by inow
    I said they had back-ups and redundancies and back-ups for those... not extra cooling systems. ... Partner.

    I'm not arguing. I'm making sure you read me correctly, and don't misrepresent my position when responding. Partner.
    Good point, sure... And please don't mock me.
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  17. #16  
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    Quote Originally Posted by MagiMaster
    Plus, the reactors themselves, while several have been essentially destroyed, aren't the source of the radiation problems. (That's from the waste stockpiles.) Overall, I'd say they've done extremely well.

    (Crossposted)
    Another good reason NMBY has to somehow get overturned, so we can start storing the waste in places that are actually safe, instead of on site.
    Some clocks are only right twice a day, but they are still right when they are right.
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