Fukushima Daiichi Worker: Reactor 4 undergoing major remodeling on 3/11 — Pipes only temporarily welded closed — I’m worried that water may leak at anytime

Published: June 29th, 2012 at 2:56 am ET
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Tweets by Fukushima Daiichi worker @Happy11311 translated by Fukushima Diary:

7:16 AM on June 28, 2012

People are only worried about the incline of the reactor 4 building or seismicity, but I’m not really concerned about that though I’m not optimistic either. What concerns me more is that reactor 4 was being under the major remodeling construction when 311 happened.

7:16 AM on June 28, 2012

For the remodeling construction, the pipes to connect to Reactor Pressure Vessel (RPV) inside of the drywell were cut off, and they were temporarily closed to wait for the replacement. It’s merely briefly welded to temporarily close, I’m worried that furnace water may leak from those pipes anytime.

Published: June 29th, 2012 at 2:56 am ET
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14 comments to Fukushima Daiichi Worker: Reactor 4 undergoing major remodeling on 3/11 — Pipes only temporarily welded closed — I’m worried that water may leak at anytime

  • Not sure what to worry about. You can always call in the army, and it will be cooled with helicopters. It was formerly known as..

    http://www.guardian.co.uk/world/video/2011/mar/17/japanese-helicopters-water-nuclear-reactor-video
    17 March 2011

    Defence force always better than the force of reason…


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  • @CB

    come out come out where ever you are…

    I just wanted to say your comment on The Extinction Protocol: 2012 and beyond; Addressing the 40 clean up plan…

    Priceless…

    Thank you for sharing wisdom to other communities aside from here… A+


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  • or-well

    Did anyone here know this? Reactor 4 undergoing "remodelling" just prior to 3/11? What does that mean?
    I wonder about this @Happy11311 person.
    These temporarily welded shut pipes were connecting -what – to the Pressure Vessel?
    Why isn't Mr. Happy concerned about Building 4's lean or seismicity?
    Is Mr. Happy feeding distraction? Sowing confusion?


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  • patb2009

    I'm okay with temporary welds as long as they are strong enough to face current conditions (Corrosion, low pressure, low temp, shake). I'm much more concnerned about the state of the CV, seals.

    At some point those are going to ail hard and then we are screwed.


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  • chrisk9

    Very interesting that they were finally doing a feedwater piping replacement 30 years after it was known it was needed. General Electric has known about this problem since these pipes cracked at Duane Arnold in Iowa in 1978, I was there in the middle of the discovery and replacement.Pipes 3 foot wide cracked and were leaking water.

    With all the fuel offloaded from the core this really means very little because water is not needed to an empty pressure vessel. But it could mean something to the fuel pool. There have been discussions here that have talked about leakage from the fuel pool gate. One answer proposed was to flood the reactor cavity so that water level in the fuel pool could be maintained. With this information this idea will no longer be an option.

    This piping replacement requires that the reactor cavity be drained very low, below the feedwater nozzles, and accordingly all fuel removed. Almost all BWR's worldwide had this replacement 20-30 years ago. But it was done without much publicity since it is rather embarrassing to have cracks in the main pipes that deliver water to the reactor.

    I have a lot of first hand knowledge of this situation, so if there are questions please ask.


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    • Wreedles Wreedles

      If replacing these pipes requires that the reactor cavity be drained below the level of the feedwater nozzles, it stands to reason that a catastrophic failure of these pipes would result in an unisolable LOCA. My initial reaction was to wonder why in the world they waited so long to repair this; the analogy I drew was that it was similar to having your fuel pump spraying gasoline on your battery, and driving the car in that condition for 30+ years rather than fixing it. On further review, I figured out why they hadn't fixed it. Money. Of course. 3 foot diameter pipes are expensive, not counting the loss of revenue from having the reactor out-of-service. I'm beginning to realize that as a species, anytime we make decisions where the primary consideration is financial to the exclusion of all other considerations, we set ourselves up for disaster.


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      • PhilipUpNorth philipupnorth

        Wheedles: You may have perfectly articulated the reason why humanity must now abandon service-to-self free enterprise, in favor of some sort of non-monetary, egalitarian, sustainable, renewable social and economic construct: "I'm beginning to realize that as a species, anytime we make decisions where the primary consideration is financial to the exclusion of all other considerations, we set ourselves up for disaster". Katrina, BP, Fuku. All the same. Couldn't afford to do things right. When things went bad, they went terribly bad.


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    • or-well

      @chrisk9 -
      So, if the "remodelling" was feedwater piping replacement, would the #4 Reactor Pressure Vessel have been mostly empty of water when the earthquake struck?

      If that was so, what is the "furnace water" @Happy11311 is referring to?

      Do you think that after the crisis developed Tepco filled up the #4 Reactor Pressure Vessel with water for some reason?

      There wouldn't be a loop to circulate water from the RPV to the Spent Fuel Pool would there?

      I apologise for being stupid about this. I've not gotten into the actual inner workings of these machines.

      I understand (I think) that the radiated Spent Fuel Pool water could drain into the Reactor Pressure Vessel through a compromised gate seal.

      Is @Happy11311s' concern that this water would then leak into the drywell through those welded shut pipes if they broke?

      Thank you in advance if you choose to respond.


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    • PhilipUpNorth philipupnorth

      crisk9: Can you please answer a couple of questions? I'm trying to determine how worried I should be about SFP4.
      First, isn't the level of the bottom of the gate between Reactor4 and SFP4 above the level of the top of the spent fuel assemblies in SFP4?
      Second, suppose the empty Reactor4 entirely dewaters, and the gate seals uttery fail. Won't the spent fuel assemblies in SFP4 still be underwater?
      Third, an auxiliary pump was added to SFP4 in order to handle the extra cooling load when the hot fuel from Reactor4 was removed in November, 2011. In July of 2012, will both the main pump and the secondary pump still be required to adequately cool SFP4? Or, could either one do the job in a pinch?
      Fourth, what is your assessment of the state of the concrete in the walls and floor of SFP4, and in the supporting columns. Will SFP4 continue to hold water? Will SFP4 continue to stand in the event of a M6-7EQ?

      I'm all about worrying about the REAL Fukuproblems. I'm also all about avoiding unnecessary FUkuhysteria.


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  • chrisk9

    Or-well and Phillip: The RPV would have had to be mostly drained to do the piping work. Don;t know what furnace water" means. Don't believe they filled RPV up after crisis, probably not possible quickly. There is no piping between SFP and RPV. Water could leak into RPV if SFP gate seals failed. No questions are stupid.

    The bottom of the fuel pool gate is above the fuel in the spent fuel pool- but not by much (guessing 3-5 feet at most) but that much water is not enough for shielding. Refueling floor would be lethal in that situation. Yes they would be underwater, but dose rates would be huge, and the reduced water would heat up so much faster it might boil. I am not an engineer, so i do not know how to calculate the heat load of the fuel pool, although I have read that is half what it was on 3-11. In a normal pool one pump is all that is needed. I have never seen a pool with 1500 assemblies in it.
    Your last question is the one everyone wants to know. Hundreds of engineers are hopefully working on this. Was sea water used to cool this pool when it was used everywhere else? If so then how much will it damage the stainless steel? (a lot) The SFP has specs that call for very exacting limits on the water-exact ph, very low solids, very low chlorine and florides. I do not know if the pool water is even being filtered like normal. Again an engineer could better answer this. But I worry too-love the FUkuhysteria comment, I totally with you there.


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