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Chernobyl new safe containment

  1. Dec 4, 2016 #1
    For many setbacks and trials and errors the nuclear industry has faced there are also major achievements , one of which I learned today as I was surfing the internet for something of interest. For all the countless people who have sacrificed their health and in many cases lives in order for many others to be safe , I personally know and knew a few that put their share into this effort.
    The new containment arc is ready and will soon be pushed over the infamous and now iconic Chernobyl nuclear power plant’s 4th reactor , or more appropriately – what remains from the reinforced concrete and metal structure that was once a nuclear reactor but turned itself to a pile of twisted and vaporized steel and concrete and the rest of periodic table.


    A video from the mysterious youtube nuclear physics activist woman with the nickname “bionerd”






    maybe someone here likes to comment how and exactly what functions will the new containment have ? will it have sort of robotic arms and tools that will slowly take apart the damaged section part by tiny part and then send those parts to a special storage place ?
     
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  3. Dec 4, 2016 #2

    Astronuc

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  4. Dec 4, 2016 #3

    mfb

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    In theory.

    In practice the containment is supposed to last 100 years. Why should the Ukrainian government spend money on disassembling it now, if they can leave that task for the next government (and so on)? In addition, they can always argue that the overall activity goes down over time, making some tasks easier in the future.
     
  5. Dec 10, 2016 #4
  6. Dec 10, 2016 #5

    mfb

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    That article completely ignores the idea of disassembling the reactor at some point, and the risk of release of additional material if the old containment fails at some point. That's like going to an operational reactior and saying "inside the containment vessel the [current] radioactiviy levels are low, this nuclear reactors doesn't need a containment vessel".
     
  7. Dec 11, 2016 #6

    mheslep

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    Eh, yes without containment there could be some weather caused release of additional material, but the containment around an operational reactor is designed to withstand explosions, large over-pressures, the release of highly radioactive gases. That's long in the past at Chernobyl. We don't build reactor type containment around stand alone waste, no matter how hot.
     
  8. Dec 11, 2016 #7

    mfb

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    It is designed as additional safety feature in case the others fail.

    The new Chernobyl containment is designed as additional safety feature in case the old containment fails.
     
  9. Dec 11, 2016 #8

    mheslep

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    Agreed. The question then is whether it was over designed given the current radiation levels.
     
  10. Dec 11, 2016 #9

    mfb

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    Well, that is the point: it is not about current radiation levels, it is also about future radiation levels. You want to have the containment before radiation levels go up, which is a risk in the future.
     
  11. Dec 11, 2016 #10

    mheslep

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    Yes, some containment. But $1.5B, 110M tall? I don't think so.
     
  12. Dec 11, 2016 #11

    mfb

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    Well, the details of the containment are a completely different discussion.
     
  13. Dec 16, 2016 #12
    Well judging by how long you have been here mheslep and your area of interests (checked your stats out of curiosity) I assume you must know the approximate physical dimensions of a second generation RBMK 1000/1500 reactor. The first RBMK reactors had each reactor in a separate reactor hall/ building with only a common turbine hall but the later reactors were incorporated into blocks by two keeping the common turbine machine hall. Stations like Smolensk have only the latter ones while stations like the Leningrad nuclear power plant have only the first types since it was built earlier , stations like Kursk and the now famously infamous and also closed Chernobyl or originally V.I. Lenin nuclear power plant had both the old style and the new ones.

    This can be easily seen in any picture from the Chernobyl plant as the first two reactors are kind of small and separate while the unit 4 had its neighbor right behind some thick reinforced wall in the same block –unit 3, which above everything else kept operating years afterwards.

    The thing why I’m saying this is that the newer double reactor blocks were not only among the most powerful fission reactors at the time but their physical structural dimensions were quite large compared to any western reactor of near similar power level. I think they were the largest in size of any other fission reactor.
    Even though it is not clear to my what difference does it make to build hem in such an arrangement since the power output is the same as the older ones.

    So when you say whether they needed 110m , well they absolutely needed 110m because the height of the roof of the reactor hall (might have changed a few metres since the original roof was destroyed and the sarcophagus built in place) is about 95 m , so technically a 30 floor building. The middle of the reactor is even higher where the chimney rests upon.

    One of my friends visited the site recently and he too said that he was amazed by the size of the reactor. I also assume from what I have read that the arc is cladded with some radiation absorbing material from inside which makes it even higher since otherwise its just a giant steel ribbon and would let wind and particles straight through it.




    The other question to which I too would like to know the answer is whether it really was worth the money , I tend to think that much like all other nuclear related stuff the dangers of the blown reactor are exaggerated , given people have even been in the ruins of the reactor hall and near the lava like rocks formations of fuel and concrete what can happen to anyone who stands kilometers away from those , pardon my ignorance but I also fail to see how wind or rain could make any significant amounts of dust and then take them miles away to do any harm , and if some are taken just a bit and settle inside the exclusion zone , what difference does it make , no one is going to reside there for the next 100 years anyway.

    Speaking of rain and moisture and wind , maybe they could have just used a batter and more sophisticated greenhouse film to cover the block and simply change it every 5 years or so.

    After all the sarcophagus isn’t the main structural support of the block anyway if I understand correctly it’s just a means of trapping all the poisons inside.




    Ok that’s a bit of philosophy right there.




    After all if I read correctly what others have said here they will not dismantle the reactor or even attempt that anytime soon even under or inside or with the help of the new arc.

    And quite frankly is it even logical and needed to dismantle the power plant especially when you have an arc that costs 1.5 billion sitting on top of another older metal and concrete shield sitting on top of a pile of crap that itself sits on mostly intact and very strong reinforced concrete structural elements and can’t pose any real danger anymore as long as it is inside and around hundreds of tons of steel and concrete. Dismantling would mean taking up space or building a new special waste site which itself would cost millions if not more then transporting etc etc and still the exclusion zone would probably not benefit from that at all.
     
  14. Dec 17, 2016 #13

    anorlunda

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    Has anyone published estimates for radiation levels at the end of the new containment's life. I'm wondering how much easier it might be to do dismantlement then? Or possibly to mine it for medically valuable isotopes.

    That exclusion zone would have a nonzero value if the contaminants were removed. 100 years from now, that nonzero value could be higher.
     
  15. Dec 17, 2016 #14

    mheslep

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    Do you mean rad levels today, at the end of the existing sarcophagus, as it's called? Rad levels 100 yrs from now (life of the new structure) are predictable, would follow half life decay. That is, the level of all fuel and waste should fall by a factor of about 20X 8x in the next 100 years. After that, the actinides will dominate.

    ActivitySpentFuel_IAEA.png

    http://www.world-nuclear.org/upload...cle/Nuclear_Wastes/ActivitySpentFuel_IAEA.png
     
    Last edited: Dec 18, 2016
  16. Dec 17, 2016 #15

    mfb

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    Based on your graph I get a factor ~8, with fission and activation products still dominating.

    Still a significant factor, and dismantling technology is unlikely to get worse within the next decades.
     

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  17. Dec 17, 2016 #16

    mheslep

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    <shrug>
    I'm starting 30 yrs post accident (appears to me from graph the activation ratio is ~10,000), going to 130 yrs (~250).
     
  18. Dec 17, 2016 #17

    mfb

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    It is a log scale. The middle between 10 and 100 is sqrt(1000)=31 years, i. e. now (30.5 years).
    In 100 years we are at 130 after the accident, log(1.3)=0.11 units behind 100 years.

    The lines in the attachment lead to the corresponding activities, and doing the log->linear conversion backwards leads to a ratio of 8.
     
  19. Dec 18, 2016 #18

    mheslep

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    Yes I know, halfway, with activity 10000

    And I had this wrong, thinking 300 (would have been in the middle again) instead of 130. Sorry for the trouble.
     
    Last edited: Dec 18, 2016
  20. Dec 24, 2016 #19
    For me the more reasonable question is why interfere in Chernobyl anymore at all , except scientific research and observation? The plant itself is now as good as any waste site probably , taking it down would simply mean lots of resources and money spent to take the trash elsewhere yet not get rid of it anyway.
    Then there is the contaminated soil and land in the area which is a separate problem and makes the demolition of the reactors themselves kind of useless since that's just one part of the problem.

    Then there is Pripyat which is full of reinforced concrete highrise buildings nearly all of which are still standing and heavily contaminated , one probably can't blow them up because the dust created would be full of isotopes and spread and get into the atmosphere.Dismantling so many buildings by tools and workers especially given the conditions is either extremely costly and or very long and painful of a job requiring too many people.


    And even if somehow one could clean the whole place up with a magic hand and make the buildings and reactors disappear the real estate value there would still be below zero because for the average public no matter what you do that place is a no go in terms of marketing.
    Haven't heard of anyone being interested in moving there... :D


    That's another topic but given our ability to use HVDC and efficient transmission why can't we build many nuclear reactors at a single destination and then just take the power to all sides as needed instead of making them each in a different location with each one having just a few reactors per site.
    Europe for example is small enough geographically that we could literally have two nuclear power plant locations for the whole continent , China manages to transport power for even longer distances just fine. Although I assume it would be a political problem rather than a physical one.

    In Chernobyl they originally wanted to pack as much reactors as they could or as the areas water reservoirs allow for sufficient cooling.
    apart from Pripyat which housed the workers families the area is very remote.
     
  21. Dec 24, 2016 #20

    etudiant

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    Think that the idea of a nuclear park is attractive at first glance, but less so on closer examination.
    When something goes badly off track, the damage gets multiplied correspondingly.
    At Fukushima, 6 reactors are now out, four at Chernobyl, so 10 reactors from 2 incidents.
    An alternative approach would be to include low probability events such as station blackout as part of the design requirements.
    Maybe that will drive suppliers towards much smaller, more flexible reactors that are individually more manageable even if things go very wrong.
    Think that aspect has to be better in hand before reactor building resumes on a larger scale.
     
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