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Wednesday, June 8, 2011

Fukushima Daiichi: Wednesday update June 8

First.. there are reports circulating in the press, seemingly particularly on anti-nuclear sites and anti-nuclear leaning big media that the Japanese are submitting a report to the IAEA that "admits" total core melt and some core material exit from the reactor pressure vessels at all three affected reactor plants.

This has been reported on this blog for months. It is not new; it is not news.

This blog may have been the first to begin quoting ORNL SBO scenario analysis indicating core material falling below the core support plate and damaging, first, lower vessel head penetrations ... which reports seemed likely to match up well with the events known at that time to have occurred and to be occurring at Fukushima Daiichi. It was probably also the first to speculate on the possible failure of the support plate and quenching of the core material in water still contained in the bottom plenum, among other things, a long while back. Readers of this blog were already aware of these kinds of possibilities and events and, upon reading this report, would find nothing new or surprising in it. This gives our readers both pro-nuclear and anti-nuclear a definite leg up.

Now, briefly, there has also been an oil spill reported at Fukushima Daini. Repeat-- this is the other plant, further south, with four reactors. This oil spill is under control and is minor.

Getting back to Fukushima Daiichi; below are the promised photos of the initial setup TEPCO will use to decontaminate water on site as early as next week if all goes well. We will show the components of this system in order. All photos courtesy TEPCO (Tokyo Electric Power Company.)

First, the oil separation tank.


Next, two views of the cesium absorption towers:



Next, decontamination equipment (TEPCO indicates this to be nuclide coprecipitation and absorption equipment):



The next .. and last .. steps shown are desalination and water treatment, although there is planned to be one further desalination and treatment step beyond this which is not yet built.




TEPCO has begun installation of 32 steel support beams below the spent fuel pool in No. 4 plant at Fukushima Daiichi. More TEPCO press releases show the location of this work, the beams as received at the plant, and two of them actually installed helping support the spent fuel pool itself.




3:35 PM Eastern Wednesday June 8, 2011
ATOMIC POWER REVIEW

6 comments:

  1. The materials management of the precipitate will be an issue.
    A French report asserts the spent precipitate volume is one one hundred twentieth of the water, which says the process leaves about 1000 cubic meters of contaminated solids to deal with.
    Separately, does anyone know if the cesium absorption media are good for the duration or will that need periodic refreshment as well?
    Finally, the new supports seem rather spindly. Can anyone with mechanical engineering expertise comment on how well these might perform in the event of an earthquake, where lateral motion is an issue, as that was their stated purpose.

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  2. @netudiant: I don't have details on the cesium absorption yet; awaiting translation of a Japanese report. Also, although the supports look kind of thin they'll be under compressive stress when installed and loaded, and I believe will be supporting the weight of the pool while the original building structure plus new external structure will handle horizontal acceleration. This is my understanding at the moment.

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  3. Another report indicated the cesium absorption medium is provided by a California firm called Kurion.
    They are privately held, so no investment issue. They claim their inorganic cesium capture medium has superior selectivity and is designed for a proprietary vitrification process. Purportedly, some earlier version of this material was used in the TMI cleanup and has been recognized as superior by the NRC.

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  4. Tall and spindly is not real good for compressive stress. Unless that is the only way they can get those elements into position. Why is there a need to reinforce the pool? Has it received damage? The weight of water in it should still be the same as normal wouldn't it? Or they looking at increasing the water level?

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  5. @keith: I would imagine that TEPCO has made some quick analysis and chosen the material for these supports properly -- given the requirements for earthquake resistance there. Yes, the building was damaged either by the quake, or by the hydrogen explosion, or both. TEPCO inspection determined, some weeks back, that reinforcement of the building was a top priority.

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  6. the spindily nature of the components is likely needed to allow them to be moved within the building.... lots of thin supports can serve the same function as fewer thick ones.

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