March 18th, 2011 – There’s Got to be a ton of loose materials floating in the SFP – I would not be surprised if the top 10 feet or so of the sfp was sloshed out

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From: Michael Corradini [[email protected]]
Sent: Friday, March 18, 2011 12:13 PM
To: Farmer, Mitchell T.
Cc: Tinkler, Charles; Lee, Richard; Basu, Sudhamay; Gavrilas, Mirela; ‘Binder, Jeffrey L.’; Grandy,
Christopher; Busby, Jeremy Todd
Subject: RE: Summary of sand option

I agree with Mitch! Water is useful and sand and lead drops as some suggest is really a technique I would not advise.

Michael Corradini, Chair
Engineering Physics
University of Wisconsin
(608)263-1648 [Fax: 3-7453
corradini(engr.wisc.edu
http://www.engr.wisc.edu/ep

Quoting “Farmer, Mitchell T.”:

> I was thinking that if there is a hole in one of these pools it’s
> probably not that large and will eventually fill with crud if you keep
> the water coming. It’s hard to keep a reactor sump from plugging, I
> don’t know why the same principal wouldn’t apply to any modest size
> hole in a SFP. There’s got to be a ton of loose material floating
> around in there.

> From: Farmer, Mitchell T.
> Sent: Friday, March 18, 2011 9:49 AM
> To: ‘Tinkler, Charles’; ‘Lee, Richard’; ‘Basu, Sudhamay’;
> Gavrilas, Mirela
> Cc: Binder, Jeffrey L.; Grandy, Christopher
> Subject: Summary of sand option

> All,

> I know there has been a lot of discussion on whether sand should be
> added to the SPFs and I want to take one last pass at it to and try to
> make my thoughts clear. To summarize though, I would only resort to
> adding sand or any other solid media into the SFPs as a very last
> resort when the site is going to be permanently evacuated and there is
> no longer hope of getting water into the pool. As long as there is a
> possibility to get water in by drops and water cannons, I would keep
> that up as long as possible given the dose limits.

> The limited information that I have access to (CNN, etc.) would
> suggest that the pools are more or less intact. The possibility of
> developing leak(s) cannot be ruled out, but the fact that the pools
> took several days to boil suggests that they can still hold water:
> Furthermore, I wouldn’t be surprised if the top 10 feet or so of the
> pool was sloshed out during the initial 9 mag quake and the many 6+
> mag quakes that have occurred since. So, this could easily account for
> the fact that the pools apparently ran dry earlier than I would have
> thought.

Here is why I don’t think adding sand is a good idea:

> Although sand can trap aerosol, it is also a very good thermal
> insulator. Thus, introduction of the sand will only exaserbate the
> fuel heatup in the pool due to decay heat, thereby increasing fission
> product release. In fact, the increased release may
> actually offset any filtering benefits that the sand would offer.

> Pumping concrete or any other type of a slurry into the pool would be
> exceptionally detrimental, limiting heat transfer to conduction alone
> (concretes and other refractory oxides such as MgO are all good
> thermal insulators), and thereby negating the convection that is
> required to remove decay heat. Although I haven’t run any
> calculations, I could actually see the fuel melting in this type of
> insulated capsule, and that could only make things worse.
> Furthermore, dropping sand from helicopters will probably lead to
> mechanical damage of the fuel assemblies which would degrade
> coolabilty more.

(They clearly didn’t care about this after Chernobyl
> as the reactor was completely destroyed by the reactivity driven core
> explosion).

> I’d keep the water going and only drop sand as a very last resort if
> the site has to be permantly evacuated.

If it comes to site
> evacuation and sand is dropped, I’d advise to keep it coarse (several
> mm) so that if/when water is readded, cooling won’t be limited by
> dryout heat flux limitations in the porous sand layer.

> I just saw an ANS email promoting pumping in a sand/water slurry.
> The water will evaporate in short order, and then what is the particle
> size of the sand that is left. If it is very fine, it will preclude
> more water coming in.
> Mitch

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