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Japan eathquake

  1. Jul 16, 2007 #1

    wolram

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  2. jcsd
  3. Jul 16, 2007 #2
  4. Jul 16, 2007 #3

    russ_watters

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    Define "safe".
     
  5. Jul 16, 2007 #4
    even if they are not safe, what alternatives do japanese people have????
     
  6. Jul 16, 2007 #5

    wolram

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    That they would not leak radiation in the event of a major earth quake, with possible after shocks, this quake was close but possibly not the worst case.
     
  7. Jul 16, 2007 #6
    Aye I was looking at the minor leak earlier, but how do you safeguard against say a magnitude 8+, you really do have to accept I think, that no matter how strong you make a building or how many defences and safeguards you put up, at sometime the big one will hit, and there's little you can do about it. Take the San Andreas fault if that really goes, God help you. With the logarithmic scale of magnitude, there really is no structure you can build that would remain intact practically.

    I did a little Google, how do you build structures to withstand

    http://www.infoplease.com/ipa/A0763403.html

    9.5 on the Richter scale?
     
  8. Jul 16, 2007 #7

    Astronuc

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    The Kashiwazaki-Kariwa plants are there - all 7 reactors. They apparently scrammed as required.

    There was a transformer fire. I think it's unit 5.

    Apparently there was a leak of radioactive water, and apparently the effluent was lower than the licensing limit, and dilution in the ocean would further decrease concentration.

    http://www.cnn.com/2007/WORLD/asiapcf/07/16/japan.quake.ap/index.html
    They will have to explain why that happened. It should not have entered a pipe which flushed it into the sea.

    TEPCO will have to do an extensive inspection of the primary, secondary and ancilliary systems.

    http://en.wikipedia.org/wiki/2007_Chuetsu_earthquake
     
    Last edited: Jul 16, 2007
  9. Jul 16, 2007 #8
    Just as a layperson, I would half to say...NO. Having been to Japan, and feeling a ever so slight{4} quake, and the after shocks after, I would say there is nothing "safe" there.
     
  10. Jul 16, 2007 #9

    russ_watters

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    As Astronuc says, there will be an investigation of the failure, and as S_D says, the potential damage due to exponentially more powerful earthquakes can be devistating. But the increasein damage level tracks with the damage to other things. So my definition of "safe" would be one that requires the magnitude of the damage to (risk of injury from, etc.) the nuclear plant to be an order of magnitude or two lower than the damage to the surrounding area.

    The nuclear plant damage made headlines because it is a nuclear plant, but the casualty count stands at 9 dead and 900 injured - none of them due to radiation. Weighed against the other risks from the earthquake, the nuclear plant is safe. Heck, given a choice, where would you rather be when the quake hits - in the reactor building of a nuclear plant, or on the ground floor of your two-story house? Or driving from Oakland to San Francisco...?
     
    Last edited: Jul 16, 2007
  11. Jul 17, 2007 #10

    wolram

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    I think i will stay in England russ :smile:
     
  12. Jul 17, 2007 #11

    Astronuc

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    Seismic analysis is part of the design process for an NPP.

    The reinforcements in the concrete and the design of the pressure vessel and piping take into consideration the accelerations due to a design basis earthquake.

    Buildings that suffer damage do not have the same design standards as NPPs since they are not NPPs and not considered as critical.

    One has to look at the mass and resistance to movement. The NPPs are massive structures.

    Buildings, which sustain damage usually sit on relatively soft ground which deforms (displaces) more easily than say denser rock. It is the lateral and vertical displacements, and consequent accelerations on the structures that causes damage.

    Japan Nuclear Plant Suffers Malfunctions
    http://www.npr.org/templates/story/story.php?storyId=11996084

    TEPCO will have to perform an extensive investigation and report to MITI. hat will include some statement on any delay of notification to the government and public. Certainly an 'uncontrolled' release of any radioactive material is unacceptable. We'll just have to wait.

    At the time of the quake, the priority is getting the plant (reactors) shutdown, which takes minutes, and secure, which takes hours. Reactor scram - i.e. shutting down the nuclear process - takes seconds, but then the decay heat removal will occur over hours, and the plant staff have to check all systems for integrity.
     
    Last edited: Jul 17, 2007
  13. Jul 18, 2007 #12

    mgb_phys

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    That might be a reasonable part of the design. You know the water isn't too dangerous and so collecting it up and discharging it to the ocean might be the least worse option in the event of a rare spill.

    Dumping a lot of dirty chemically contaminated water into local water courses is normally bad but we accept it when fire engines put out a fire.
     
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