Something is Strange here..

Post #340,549 by Ashton 3/15/11 5:19:48 PM Reply	Something is Strange here.. It is intuitively obvious even to a techno-illiterate: via bucket brigade, fire hoses or borrowed helicopters from US or other ships converging: GET MORE WATER INTO THOSE POOLS, STAT! Talking doesn't cook the rice -- Shinto too, likely has an equivalent koan. And yes, some heroic overexposures, maybe to the 100 REM / I Sievert dose level are likely unavoidable. Many Pripyat folks made a larger sacrifice, fully aware of the ~440 REM MLD (median lethal whole-body dose) -- handling actual KiloRad-hot pieces with inadequate, up-close tools ... or gloved hands. [Unless, of course, they have run out of All Options re China Syndrome in-reactor probabilities, in their informed opinions.] Yet, considering the number of Mega-Curies of awfulness within that pool (adjacent to an empty reactor) -- consisting of n- core-loads of accumulated fission products: the storage pool still qualifies for all last-ditch efforts to submerge those suckers, even at $10/gallon delivery overhead. I don't understand this level of impotent inactivity, at all.
Post #340,552 by Another Scott 3/15/11 5:53:47 PM Reply	It seems they can't. Either they can't reduce the pressure in the reactors enough to pump water in, or there's a blockage, or there's a big leak. Or all 3. What I picture happening is a combination of things: 1) There's hot fuel in the reactor because of a drop in water level. Some of the fuel rods have melted. 2) They vent the excess pressure, leading to even more water boiling away (lower pressure means easier boiling). 3) They pump in water, which instantly turns to steam when it contacts the hot fuel rods, increasing the pressure and making it more difficult to pump more water in. 4) Goto 2. What I haven't heard anyone talk about is: How effective are the control rods when they're embedded in molten fuel rods? Obviously, it's difficult for water to get to the center of a hot blob of metal, but isn't there also danger of some increased level of fission reactions starting up again since the control rods can't do their job? IOW, under normal circumstances the reactor cools down in a few days once it's been "scrammed". Does that still hold if the fuel rods have melted? My understanding is that the control rods "suck up" neutrons and stop the fission chain reaction by reducing the number below a self-sustaining level. But the control rods are designed to be a certain distance from the fuel, or in other words, the fuel rods are supposed to be a certain distance from their neighbors, to control the fission reaction. If everything's melted together, there's nothing to control the reaction (with the important caveat being lack of a moderator to slow the neutrons down), so even if the reaction won't be efficient, it can still heat up the fuel even more (more U atoms are closer together than designed), causing more melting, etc., etc. I haven't seen anyone talk about that, and it bothers me. In other accidents (TMI, the Fermi breeder outside Detroit), the core partially melted, so there must be some way (in principle) to prevent it from running away or staying hot for decades. But in those cases, 1) they weren't BWRs, and 2) they didn't suffer loss of coolant anywhere near as severe as some of these TEPCO reactors apparently have. How much of that history transfers here? I don't envy the folks working there. :-( Keep an eye on the prevailing winds, all of you West-Coasters.... :-( Cheers, Scott.
Post #340,553 by boxley 3/15/11 5:58:53 PM Reply	drift chart http://10373f8b.tinylinks.co/ Any opinions expressed by me are mine alone, posted from my home computer, on my own time as a free American and do not reflect the opinions of any person or company that I have had professional relations with in the past 55 years. meep
Post #340,554 by folkert 3/15/11 7:31:19 PM Reply	Getting us back for WWII?
Post #340,558 by Andrew Grygus 3/15/11 8:33:12 PM Reply	Well, if nuclear power isn't dead yet in the U.S. . . . . . 750 rads on the coast of California will certainly do the job.
Post #340,559 by Another Scott 3/15/11 9:13:16 PM Reply	I didn't address the fuel storage areas before, obviously. http://www3.nhk.or.j...nglish/16_05.html TEPCO: Spraying water from air "difficult" Tokyo Electric Power has found it difficult to spray water from a helicopter to cool down a storage pool for spent nuclear fuel inside the No.4 reactor at the Fukushima Daiichi nuclear power plant. The reactor was undergoing an inspection when the quake occurred. The firm says the temperature of the storage pool for spent nuclear fuel was 84 degrees Celsius on Monday morning, more than double the normal level. More recent temperatures are not available due to a technical failure. On Tuesday morning, an explosion was heard and the roof of the building that houses the No.4 reactor was damaged. Tokyo Electric Power, the operator of the plant, says it appears a lack of coolant caused the fuel rods to be exposed, adding that a hydrogen explosion might have occurred. If the reactor can't be cooled, the fuel rods may emit hydrogen or melt down. Tokyo Electric Power considering pouring water onto the storage pool in the containment vessel through a hole on the roof created by the blast. However, the firm concluded that it would be extremely difficult to spray water from a helicopter as the hole is dozens of meters from the storage pool and a helicopter can only carry a limited amount of water on a single flight. Workers are currently unable to approach the storage pool due to the high radiation levels. Tokyo Electric Company is studying the possibility of using fire engines and other options to inject water into the reactor. Wednesday, March 16, 2011 03:04 +0900 (JST) TEPCO apparently presented a paper in November on how they do wet-storage and dry-storage of fuel bundles. http://www.nirs.org/...-1_powerpoint.pdf (26 page .pdf) Most of it is over my head, but it sounds like there's a lot of fuel being stored there, and they recently "upgraded" Fukushima-Daiichi Unit 1-6 to let them store even more... - Increase the capacity of spent fuel pools by re-racking - Installation of common spent fuel pool - Installation of dry cask storage facility Aye Carumba! :-( The wet storage facility is in slides 9-11. HTH. Cheers, Scott.
Post #340,560 by Ashton 3/15/11 10:54:18 PM 3/15/11 11:07:35 PM Reply	Aye, TMI (info, not 3Mi-Island) of generic kind -- way too little from which one can deduce useful things. Understandably, the sorts of details we'd like some accurate info about just won't happen until in retrospect; neither time nor patience to bring in a sci-literate 'scribe + camera' to get the words out. Bring your own floodlights and lunch? Among the minefield of unknowns: whether the tsunami immersion so screwed up pumps, temp/px monitoring sensors, hyd. actuators and controllers -- that even were a US flattop to bring in a self-contained AC power unit via a huge Huey: Would much of the stuff and its controlling electronics still function? But how such things as, say the Px-relief valves in the torus? can be operated at all without AC power from Somewhere? -- I don't grok (either.) As to intermixed Boron and elephant feet blobs, it seems a mares nest of not-calculable cross-sections; if cooling of the blob-surfaces could.. be accomplished, then further neutron absorption could come from concentrated borate slurries, one supposes. No need to ponder moderators and spacings, I'd think: what you want is lots of the best n-absorbing substance available. By express Lear Jet. But this is rapidly ceasing to be an enviro where a robot could eat the Rads, even to haul a fire-hose end up to a steaming pool, given a debris-covered floor (We don't even know if any? many? of these pools' 'containment integrity' has been compromised) And it seems that TEPCO's workers/mgment have also PO'd the government minions, having failed to inform of the 6am-ish most recent fire, for some hours. Who's not leveling with whom? Apparently it was machine lube oil which was burning at #6 following the (alleged) release of nascent-H via water + overheated Zircalloy spent-rod cladding, that which caused that explosion. Watch and wait.. PS: NYT is collecting (intelligent) questions today, to be 'answered' tomorrow by whatever selection of boffins they have managed to corral: http://green.blogs.n...n-japan/?ref=asia Some noticed, appear to be al punte ... re several of those puntes. Edited by Ashton March 15, 2011, 11:07:35 PM EDT Expand All History
Post #340,561 by Another Scott 3/15/11 11:37:41 PM Reply	Thanks. The BBC is reporting that a government spokesman said the 50 remaining workers are being withdrawn (Temporarily? Who knows...) due to excessively high radiation levels. http://www.bbc.co.uk...-pacific-12755739 :-( Cheers, Scott.
Post #340,606 by Ashton 3/17/11 1:57:19 AM Reply	NYT answers to selected Qs submitted yesterday http://green.blogs.n...-crisis-in-japan/ Seems to be in (expected) decent English, without garbling of concepts ... on a quick scan of replies. FWIW
Post #340,612 by Another Scott 3/17/11 7:59:14 AM Reply	Good Q&A. Would be nice if more reporting was like that...
Post #340,563 by jay 3/16/11 12:19:58 AM Reply	It's the spent fuel containment pools I'm guessing the reactors are all cooling now, and they just need to wait till they cool enough. The problem now seems to be the containment pools for spent fuel. These pools are elevated above the reactor, so if the pools are damaged there isn't a simple way to fix it. They don't want to just dump water from above because the whole building might break up. The fire at the number 4 reactor almost has to be burning fuel rods. That reactor was not only off-line but had the fuel rods removed from the reactor when the disaster hit, so the only thing there to be spewing radiation is the spent fuel rods. As ugly as it would be, I think they are going to have to ask for volunteers to go in and deal with it. They are going to need fire fighting crews and engineering teams to jury rig repairs. It's going to be a suicide mission, but it's probably the only way now. Jay

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