John, Thanks for the perspective. You have a lot on your plate right now. Save some energy to deal with the therapy. Hope your computer problems resolve soon. Regards, Bob S.
On Thu, Mar 17, 2011 at 12:05 PM, John Sessoms <jsessoms...@nc.rr.com> wrote: > From: Joseph McAllister > >> On Mar 16, 2011, at 17:00 , eckinator wrote: >> >>>> I would kind of think that all this pumping of water onto fuel >>>> rods glowing at somewhere between 800 and 2500 ?C would cause >>>> instant evaporation and the corresponding shock waves of pressure >>>> rises; AFAIK water expands 1700fold from liquid to vapor/gaseous >>>> after all. wouldn't that cause enormous stress and ultimately >>>> fatigue of the containment vessel? and are the pressure relief >>>> valves designed to withstand this abuse for an extended period? >> >> That is the challenge, once the fuel rods are uncovered. They get so >> hot that trying to cover them again with anything that could help >> reduce or stop the loss of coolant creates more steam which becomes >> volatile in contact with the hydrogen being released by the degrading >> fuel rods because it presents free oxygen to an increased amount of >> hydrogen. Like H3 0. >> >> So the helicopters that are currently (as I write this on Thursday >> morning Japan time) dumping water on the hot (burning at times) spent >> fuel rods would have to dump a lot in a short period of time to >> prevent it being boiled off instantly. They should be, and may be, >> dropping a slurry of water and sodium hydroxide (I think hydroxide, >> maybe not). >> > > > The containments are already breached. > > But the place where the helicopters are dumping water is a storage pool for > spent fuel rods, not inside the reactor. I think they've managed to get some > cooling water into the reactors. > > I'm wondering how the water got out of the storage pool. The ones I'm > familiar with are massive reinforced concrete structures with walls many > feet thick set below ground level. > > The ones I worked on back in the late 70s had walls & floors 10 feet thick, > all poured in one continuous pour. They had multiple layers of #18 rebar on > both the inside and outside faces with thousands of tie rods linking the two > faces. The earthquake might bounce it around a lot and it should stay > intact. > > An earthquake strong enough to breach structure like that wouldn't leave > anything else standing, and I can see that there are towers and buildings > still standing at the site. > > To get water out of the storage pool you had to suck it out uphill. There's > supposed to be enough water in the pool to cover the spent fuel rod bundles > and keep them cool even if they temporarily lose the ability to add water to > the pool. > > If the pool is breached in some way that it has drained, they can't dump > enough water from helicopters to bring the reactions under control. They're > going to have to get multiple water pipe into that building to get control > of the situation. > > Chernobyl was a dry pile design and the helicopters there were dumping sand > and cement on to the exposed core. The sand and cement didn't flow away like > water will. Over time it built up in layers to contain the reaction so that > they could get a more permanent cap in place. > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
