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View Diary: Fukushima Status Update Summary (289 comments)

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  •  Thanks for the info (3+ / 0-)
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    HoundDog, DawnN, erush1345

    There might be a little confusion on the part of CNN.  I say this because the initial connection of the outside power was being done at unit 2.  Power for the other units was to be distributed from there.  Yesterday they connected portable generators to units 5 and 6 and got the fuel pool cooling started.  That may be the basis for CNN's report.

    The situation with the shifting winds is addressed in FishOutofWater's diary that is referenced in the first update.

    Free: The Authoritarians - all about those who follow strong leaders.

    by kbman on Sun Mar 20, 2011 at 04:04:02 PM PDT

    [ Parent ]

    •  Getting the pumps restarted in unit's 5 and 6 (1+ / 0-)
      Recommended by:
      kbman

      is about the best news we've heard yet, is it not?

      And, if I understand your diary correctly, all the external pumping connections are intact?  

      I had been misinformed then, that a lot of that was destroyed in the earthquake and subsequant explosions.

      If the cooling pump mechanisms, are intact, then the new electricity should allow cooling to begin immediately, which will quicky turn around all the troubles.

      I had read earlier that the water in the cooling ponds is typically 45 feet, and the rods don't expose until its down to 15 feet.  

      And, because the spent fuel is typically significantly less active in heat producing capability, that under normal circumstances cooling ponds can last anywhere from 4 days to 2 weeks without cooling before enough water  boils off to espose the rods.  

      If these ponds become accessable, additional water can be added to keep them covered, to prevent fires in the cladding, which has been the greatest risk, from what, I've heard.  

      As, long as any melted uranium pellots, are kept within the containment domes, the risk of particulate release is contained.

      Does this sound right?  As long as we can keep these pools, and the reactor cores cooled, then we will have a much more stable environment, to handle damaged fuel in the core, or in the ponds.

      And, my understanding is that as long as we recover the spent cooling ponds to keep them from burning, the fact that they may have been partially damaged, does not matter as much.

      The biggest danger is from an uncontrolled fire, in an completely dry spend fuel pond.  But, that if we can get them recovered with water, and from boiling then we shouldn't be in danger of any really big releases?

      The means is the ends in the process of becoming. - Mahatma Gandhi

      by HoundDog on Sun Mar 20, 2011 at 04:18:10 PM PDT

      [ Parent ]

      •  Various issues here ... (8+ / 0-)

        I think it would be quite optimistic to say that all of the external pumping connections are intact.  We do know that several of the pumps and cooling systems worked in the hours after the earthquake.  Given the size and location of the hydrogen explosion at unit 1 it is likely that most if not all of the systems there survived intact.  The same cannot be said with near as much confidence regarding unit 3.  At the same time, given redundant systems and multiple locations for equipment, I have reason to believe that at least one of the core cooling systems will be available once power is connected.  I suspect that pumping abilities for the fuel pools at units 1 and 3 were damaged by the explosions but do not know enough about their physical layout to know with any certainty.  Unit 4 did not have nearly as strong an explosion, but damage is still possible there as well.

        Regarding access to the fuel pools, I read that they are looking into using army tanks to clear debris from the rubble piles at units 1 and 3.  I'm not sure how they intended to do this, but any clearing up there will help tremendously in being able to manage the situations in the pools.  They just need to be careful and not cause more problems than they are solving.

        And yes, as long as the melted fuel stays in the reactor vessel it is fine - provided they keep it borated to prevent criticality.  The boric acid in seawater acts as liquid control rods to prevent any of the melted fuel from restarting a nuclear reaction.  It should also not present much of a contamination risk in the vented steam due to the weight/density of uranium and plutonium.

        And yes, as long as they are able to keep the spent fuel under water now and prevent a fuel pool fire then the condition of the stuff underwater is not that crucial from a public safety viewpoint.  Being deformed and partially melted makes the cleanup effort more complicated, but as long as it stays cool and covered it no longer presents an immediate threat to the public.

         

        Free: The Authoritarians - all about those who follow strong leaders.

        by kbman on Sun Mar 20, 2011 at 05:54:59 PM PDT

        [ Parent ]

        •  Well, cross fingers... (2+ / 0-)
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          Drama Queen, kbman

          After the sequence of disasters they've had, I think we'll be very lucky if they manage to keep all the fuel piles underwater.

          Read pp. 1-7 of Krugman's _The Great Unraveling_ (available from Google Books). NOW.

          by neroden on Mon Mar 21, 2011 at 07:14:33 AM PDT

          [ Parent ]

          •  Well, I think they're due for a few lucky breaks (0+ / 0-)

            Given that the folks on the ground dealing with this know the stakes involved I find it hard to believe that they will let that happen.  Even if there are leaks it just means they need to add faster than it leaks.  They have demonstrated an ability to deliver massive tonnage of water to these pools.  I think they'll be able to sustain the effort.  It took at least a few days for them to drain down to where fuel was uncovered so it's not like they're gushing water out of the leaks.

            I would also think that a key priority would be getting a handle on exactly where the leaks are and what their extent is.  It may be that some structural support in a few key spots could help provide a greater margin of safety regarding potential further damage.

            Free: The Authoritarians - all about those who follow strong leaders.

            by kbman on Mon Mar 21, 2011 at 10:13:21 AM PDT

            [ Parent ]

            •  Radiation's Probably Too High (0+ / 0-)

              ... to shore up the pools. I think what they might fear most is that whatever structural defects exist will only get worse as they pump water back into the pools.

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