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Are there any nuclear power plants on oceanic coastlines like Fukashima?

  1. Jan 26, 2013 #1
    Are there any nuclear power plants on oceanic coastlines like Fukashima Daiichi which are vulnerable to being damaged by powerful tsunamis and earthquakes?

    Do any of these coastal plants exist in the United States?
     
  2. jcsd
  3. Jan 26, 2013 #2

    Simon Bridge

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  4. Jan 27, 2013 #3
    Could a repeat of the Fukashima Daiichi nuclear disaster occur again?
     
  5. Jan 27, 2013 #4

    Simon Bridge

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    Of course it could. The trick is working out the likelyhood - identifying the realistic risks and minimizing them.

    You realize that Fukushima is not the first nuclear reactor to melt down right? Earthquake and tsunami are not the only ways they can break?

    This is why the nuclear power industry is regulated.
     
  6. Jan 27, 2013 #5
    Are there any nuclear power plants in North America that are directly on the Pacific or Atlantic coastline?

    If so, a MASSIVE tsunami could severely damage one of them and cause a nuclear catastrophe like what we saw in Japan.
     
  7. Jan 27, 2013 #6

    Simon Bridge

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    In a previous post I linked to a bunch of maps - go look.
    With "could" being the operative word. What you want to know is what precautions have been taken for that eventuality and how confident you can be that the precautions are being adhered to.

    Do you have a specific science or Nuclear Engineering question?
     
  8. Jan 27, 2013 #7

    Astronuc

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    Yes - San Onofre and Diablo Canyon plants are on the Pacific coast, and there are several on the Atlantic coast. The Atlantic Coast does not have the same tsunami risk as the Pacific coast, and the eastern Pacific doesn't seem to have the same tsunami risk as the western Pacific, because the subduction zone in the east is not as significant as the western zone.

    Not necessarily. The plant systems at Diablo Canyon and Songs are at higher elevations than Fukushima, they are more protected, and they are of different design.
     
  9. Jan 27, 2013 #8
    What about the wall that is supposed to protect the plant from a tsunami? The one at Fukashima was not tall enough.

    What has the nuclear energy community done to prevent a Fukashima-like incident from happening again? Have changes or safety upgrades been installed at NPP's throughout the world?

    The emergency diesel generators at Fukashima were located in the basements of the turbine buildings. These were completely flooded after the tsunami and rendered useless. If they were located at a higher elevation, they might have been saved.
     
  10. Jan 27, 2013 #9

    Astronuc

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    US plants were designed with more safety features than Fukushima Daiichi. Apparently some upgrades that were made to US plants were not implemented in Japan. Since Fukushima, every site has done a review of their systems for vulnerability to beyond design basis events, including combinations of natural phenomena.

    There are indpendent reveiws by US NRC and INPO, in addition to industry reviews. There are various ongoing programs to monitor fire safety, diesel generators, and various safety systems, as well as vessel integrity programs.

    And the fuel storage tanks were on the shoreline and were taken out by the tsunami.
     
  11. Jan 27, 2013 #10
    The spent fuel pools in reactors 1-4 boiled dry and one of them even caught fire.

    Right now, they have a huge crane with a water hose running through it that is constantly pouring water into the spent fuel pools to keep them cool.

    I wonder if they can get the main water pumps working again at the plant, if they haven't been destroyed or damaged beyond use.

    Supposedly, TEPCO claims that they have achieved cold shutdown in all four affected reactors, even though the cores have melted through the base of the reactor pressure vessels and the molten blob of corium is either laying directly beneath the reactor, or has burned it's way through the steel and concrete floor of the reactor building and into earth. I think I remember reading somewhere that the engineers had found a way to flood the reactors with seawater in order to cool the melted cores enough to prevent a melt-through.

    It could take at least 10 years until they accurately assess the damage to the reactors and the location/condition of the melted fuel. Hopefully it has not burned it's way through the Earth in a "China Syndrome" scenario.

    On the up-side of things, scientists have estimated that the Fukashima Daiichi nuclear incident is about less than 1/10th the severity of Chernobyl in terms of radiological release. At Chernobyl, the reactor itself violently exploded and much of it's core was ejected directly into the environment. The reactor became a gaping hole with burning core exposed directly to the outside environment.
     
    Last edited by a moderator: Jan 27, 2013
  12. Jan 27, 2013 #11

    Astronuc

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    I'm not aware that any of the spent fuel pools 'caught fire'. Please provide the evidence or cite the source of such a claim.

    The core of unit 4 was already off-loaded and sitting in the spent fuel pool.

    What is the source of one's information?
     
  13. Jan 27, 2013 #12
    No pools lost their water. Analysis showed that the hottest pool, #4, was still several days away from boil down.

    As for main pumps, that doesn't matter. They installed a new closed loop cooling system for all units. The ECCS pumps may need a lot of rework to be usable again.

    TEPCO has achieved cold shutdown. Read the fukushima links to see all the data, and there is a LOT of it.

    The nuclear industry in the US already has had special procedures for dealing with extensive damage, along with portable equipment. In light of Fukushima, the industry started the FLEX initiative, which streamlines the procedures and equipment used for responding to beyond design accidents and updates all the equipment and procedures. Additionally, the US industry set up 2 regional support centers which can deliver portable equipment to any plant in the country within 24 hours. The US already has done full seismic and flooding walkdowns looking for any vulnerabilities in flood protection or earthquake detection. The US NRC has issues orders requiring the Mark I and Mark II GE reactors to have hardened reliable vents (Mark Is installed them on their own years ago in the US, now they are getting standardized as well), they also issued orders for dealing with these beyond design basis events which are not caused by hostile attacks and new rules for spent fuel pool monitoring.

    I think you should read the Fukushima posts on physics forums. This report and its appendicies are excellent. http://icanps.go.jp/eng/final-report.html [Broken]

    Also look up INPO IER 11-05 revision 1 and its supplement (both are publicly available on the NEI website). That's a writeup by the US industry which contains a lot of stuff from the plants, as well as what went right and wrong.
     
    Last edited by a moderator: May 6, 2017
  14. Jan 28, 2013 #13
    So if the spent fuel pool in reactor #4 did not boil dry and the core was fully off-loaded to the SPF for maintenance purposes, why was there a fire and explosion in that particular unit? The reactor was de-fueled and completely empty.

    Here is a photo of the badly damaged and burned building for reactor 4. Obviously there was a fire and an explosion.

    reactor4.jpg
     
  15. Jan 28, 2013 #14
    I think the explosion was caused by hydrogen production from the oxidative reaction of Zircaloy (fuel cladding) and water. The hydrogen was vented from the primary containment surrounding the reactor but overloaded the catalytic recombiners (designed to prevent the build-up of a hydrogen-oxygen mix) due to the rate of hydrogen production. So it wasn't technically the spent fuel 'catching-fire'.

    Also bear in mind that nearly all of the structural damage seen in this picture was caused by the tsunami.
     
  16. Jan 28, 2013 #15
    The core had been entirely removed from reactor 4 (for maintenance) and was stored inside the SFP during the time of the accident. Therefore there could not be any hydrogen-producing reaction inside the reactor because it was empty.

    Could boiling spent fuel pools produce hydrogen gas?
     
    Last edited: Jan 28, 2013
  17. Jan 28, 2013 #16
    I beg your pardon, thank you for the correction. I presume the hydrogen gas came from one of the other reactors then.

    As for the spent fuel ponds, I'm not sure if you would be able to get to the required temperatures for any appreciable zircalloy-water oxidation, since it's not the same environment as a reactor. Perhaps someone else can clarify this.
     
  18. Jan 28, 2013 #17
    It was investigated by Japanese, discussed to death, and by now it is well-known what happened: hydrogen was vented from Unit 3 and due to a faulty design of the common vent stack, part of it ended up entering Unit 4 and later exploding there.
     
  19. Jan 28, 2013 #18
    Good question.

    I can only say that nuclear industry seems to be rather inept at PR. I *assume* they did some safety upgrades, but sure as hell they failed to use it as a PR opportunity to show the general public that they reacted swiftly and decisively on the lessons of Fukushima.

    In fact, I didn't see any swiftness in the reaction. NRC is glacial as usual...
     
  20. Jan 28, 2013 #19
    The standby gas treatment systems from unit 3 and unit 4 exhaust to the same common stack vent.

    When the power failed, as is typical for BWR plants, the standby gas treatment system is automatically lined up to provide containment vacuum. Remember there was just under an hour between AC power failure and tsunami inundating the plant. The SGBT system dampers from Fukushima fails "As Is" (based on the last time I saw drawings/reports on it). As a result, when the unit 3 containment was vented finally, hydrogen escaped to the unit 3 secondary containment, through the SGBT filters (the open vent path), and some of that escaped into unit 4, where it concentrated enough to cause an explosion.

    Unit 3 had a very large explosion. There was a LOT of hydrogen generated. With that much hydrogen, its very feasible for an amount of it to migrate to unit 4. Remember that hydrogen only requires 4% concentration in atmosphere to be explosive. Also the SGBT system itself is situated in Mark I reactors about 2/3rds of the way up inside the secondary containment (reactor building)

    There are plenty of TEPCO reports on this as well as an analysis which shows that enough hydrogen was generated, and the necessary lineup was established, to allow hydrogen to migrate. Analysis also showed that the spent fuel pool of unit 4 had a couple days prior to full boil down, and the fuel/clad reaction in fuel only occurs above something like 1700 degrees F (not positive on exact number, but 1700 is when fuel embrittlement starts occurring), which cannot physically happen with water around the fuel, as the boiling effect would limit the fuel cladding temperatures to a few hundred degrees

    Honestly though, I'm going off of memory on a lot of this. read the hydrogen section for unit 4 here: http://icanps.go.jp/eng/03IIfinal.pdf [Broken]

    seriously you should read the report i linked. it's got all the technical details in relatively plain english (compared to most nuclear industry reports) and will likely answer your questions
     
    Last edited by a moderator: May 6, 2017
  21. Jan 29, 2013 #20
    nikkkom
    Why the explosion at unit № 4 was not like an explosion unit № 1 ?.
    Hydrogen would go up, because after the destruction of the ventilation pipe passed day.
    Maybe there was another way for passage of hydrogen.
    Common adverse communication with underground block № 3 ?

    Besides a lot of secrets in connection with the actions of the U.S. army to extinguish the fire at unit 4.
    Maybe it is, they opened the gate between the exposure and swimming pool reactor.?


     
    Last edited by a moderator: May 6, 2017
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