Most informative article yet. With fuel inventories!

Ronny keeps finding the great links. I just missed it until now.

Let’s see: sober and informative reporting, excellent visual aides, near-current conditions (because I’m late linking), what’s been done, what’s going on, challenges ahead…plus a video timeline on YouTube! It gets watched as soon as this goes up.

Also, fuel inventories for each reactor and fuel pool. A glance at it will show you why pool #4 is of most concern.

oldHP reminded me that some of that is brand-new fuel. On the sinister hand, more fissile material. But on the right hand, no decay heat. If old fuel sagged and slagged down while the new didn’t, you’d expect the two groups’ distance to increase no matter the current configuration.

Thanks as always, Ronny.

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About wormme

I've accepted that all of you are socially superior to me. But no pretending that any of you are rational.
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6 Responses to Most informative article yet. With fuel inventories!

  1. crosspatch says:

    I just listened to a press conference with the chief of the fire brigade responsible for the spraying operation on unit 3. He said that at some point during the spraying, the radiation level from unit 3 “dropped to near zero” which he took as an indication that they had been successful in covering the spent fuel rods in that unit.

    He also stated that according to personal dosimeter readings, the highest dose received by any worker in the operation was 27mSv.

    They are planning to dowse unit 4 today but need to reposition their equipment. The original plan is unworkable, he said, because of debris in the area that prevents them from positioning the vehicles as they had originally planned.

    It would appear to me that unit 4 would be the “hottest” as it would contain fuel rods recently unloaded from the reactor. It was also stated in an earlier press conference that the concrete along one side of the pool was now missing but the steel “bathtub” structure was intact. That would imply that the pool can still hold water but a considerable amount of shielding is missing along one side of the pool.

    Question: Do they risk causing damage to the spent fuel rods by hitting them with cold water and would that loss of shielding by the loss of the concrete wall allow significant gamma radiation even if they were to fill the pool? I don’t know how far from the sides of the pool these spent rods are positioned. NOTE: my background is electrical engineering (electronics design), not nuclear engineering.

    • wormme says:

      Excellent news about unit#3, and very informative comment. Thank you!

      I assume they’ll pour on the water when they can. Sound’s like they’re just looking for the best angle of attack. They want to get #4 down to “near zero” as well. To do that they’ll gladly (and hopefully metaphorically) suck up radioactive steam to get it covered again. The additional release is a pittance compared to what’s come before.

      Even if bits and pieces break off, they normally have a 25′ vault to escape the pool. So as long as there’s no literal blowback on the workers, they won’t care about damaging the fuel at this point. IMHO.

      They seem confident that they’ll be able to get water in, so even if the missing concrete makes some areas inaccessible apparently they have others. You’re right: the distance from hot fuel to damaged area will determine whether water shielding makes up for the concrete.

  2. crosspatch says:

    Another thing they mentioned is that once they get the boom positioned and get the spray going satisfactorily where they want it, personnel can leave the equipment and it can continue unattended. They have a supply line from the boom truck to a pumper truck some distance away. The only time they need to approach the vehicles is to refuel them. The last operation on unit 3 lasted 11 hours. They had originally planned 7 hours but it was going well and they realized that the equipment could operate unattended, so that is what they dud.

    Also, latest news is that power is now connected to units 1 and 2. Plan is to bring up sensors and such first so they can get an idea of what is going on in the reactors and then attempt to bring up systems for management of the reactor. (Source NHK Japan).

  3. Engineer Bob says:

    You may have posted this link before, but NYTimes has an excellent satellite photo of the power plant, comparing before the earthquake to after the hydrogen explosions. There are a bunch of other areas compared too.

    I’d call it a blink comparitor, but it’s a slide comparitor.

    photos

  4. Sparkey says:

    The above article referenced this abc7 report that shows UC Berkley Nuclear Engineering Grad Students heating up a Zirconium clad fuel rod with a blow torch and it (gasp) didn’t catch fire!

    Can we put this myth to bed now?

  5. Ronny says:

    I’m happy to help, especially given what I have been learning from this site.

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