there is a bed of graphite under the containment vessel

Post #340,511 by boxley 3/14/11 5:52:23 PM Reply	there is a bed of graphite under the containment vessel so even if it melts the floor it is not going anywhere 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 #340,513 by Another Scott 3/14/11 5:59:17 PM Reply	It'll stop going down, but maybe not out in the air... Hot things have a habit of ending up in the air when they're forced to cool down rapidly. Again, I don't expect the containment vessel to fail in a major way, but there's still a significant chance of a lot of radioactivity being released. Everything isn't "under control" no matter how many nuclear engineers say there's nothing to worry about. Cheers, Scott.
Post #340,515 by folkert 3/14/11 6:10:23 PM Reply	but there's still a significant chance of... You dieing in the next 100 years. Come on Scott... these weren't Russian Power Plants. There were designed by Anal Retentive Japanese Engineers and GE engineers that thought they were crazy for the over engineering they were doing.
Post #340,516 by Another Scott 3/14/11 7:00:14 PM Reply	Yes, they're not exposed graphite piles. Yes, the steel pressure vessel is probably going to hold. At least, mostly. But they guys in Tokyo who are in "full-scale panic" are probably in a better position to know what's going on and how bad things are than a writer for TheReg in the UK. The plant is 40 years old. It doesn't have the latest safety measures that many later plants have. At least one reactor was scheduled to be shut down this month. Who knows whether some important maintenance was put off as being unnecessary or not cost-effective. http://en.wikipedia...._nuclear_accident Even anal-retentive engineers and maintenance technicians make mistakes. These TEPCO plants have had some issues in the past - http://www2.jnes.go...._power_index.html and http://www2.jnes.go...._power_index.html All commercial nuclear plants that have suffered major accidents have experienced things that the designers didn't intend or didn't consider. That's the nature of complex engineering projects. Perhaps the steel containment vessel will perform admirably for all of these at-risk reactors. I suspect and hope that they will. But I'm not at all pleased by all of the "everything's fine, it's working as designed, it's no big deal, what's everyone upset about" attitude in much of the reporting on this. This is a big deal and wasn't supposed to happen. The safety measures were supposed to ensure that the fuel rods didn't suffer from lack of coolant even in severe circumstances. The world needs to get off of burning stuff for power and transportation. Nuclear should probably have a larger role, but it's not at all clear to me that large-scale power reactors are the way to go. There comes a point where there are too many conceivable failure mechanisms that could result in large enough probability of vast contamination of the environment for the technology to be economically viable. The Shuttle solid-rocket booster O-rings had a 100% "safety margin" when they were half burned through, too... We know how that turned out. :-( The nuclear advocates out there in the press need to take what's happening to TEPCO's plants seriously. They shouldn't take the concerns as being fears of Luddites who don't know any better. If this disaster gets even a little bit worse, it may spell the end of commercial nuclear power plants in the democratic world. A substantial fraction of the population (and maybe a majority) has to support it for it to go forward, and they won't if there are continued explosions and stories in the press that the operators can't do what they say they need to do - no matter what people who "know better" say. "Who you gonna believe? Me, or your own lying eyes?" My $0.02. Cheers, Scott.
Post #340,517 by Ashton 3/14/11 7:59:25 PM Reply	Demonstrably, their major error re all the diesels was: >> NOT putting the fuel tanks UNDERGROUND!<< (As in US and most other places, I presume: this would seem to be a real Brain-Fart within an otherwise punctilious/conservative design approach elsewhere.) Tsunami is a Japanese word! and earthquakes are their daily bugaboo. Above-ground tanks supplying their BACKUP (only ONE! == another error) for the absolutely necessary mondo core-cooling pumps is, in hindsight: absolutely an inexcusable Duhh-grade oversight. Pity.. For those being queried about 'reactors', One more Time -- save your breath: here's a video by a avuncular Brit physicist, reviewing the BASICS, including the role of Boron in the control rods and various other simple concepts of the sort, always mangled by Murican-HS-edjakated talking heads, who majored in bizness. http://www.youtube.c...tch?v=-bcrLiATLq0 As to the 'mood' of Japanese boffins du jour; I seriously doubt that they are in panic-mode -- rather they are fully aware of what Might.. occur if even a few hasty/stupid actions were to be taken, next. Clearly the infusion of sea water has forever decommissioned each reactor where used: all SS parts shall have been corroded and filled with micro-cracks via Cl and other ions at v. high temps -- beyond any hope of salvage. Fortunately these reactors were already scheduled for denouement after 40 years of decent service. Concur that any Cs, I-131 etc. came from some spot in core where the Zr cladding had disintegrated (probable source point for voluminous H generation for the explosions) -- but How Many grams/kilos really did melt?? More disturbing is the inability to raise the sea-water level to cover fully the entire core == SOON. WHY?? It is almost unthinkable that there exists already a sizable hole at bottom of containment vessel, and surely they have opened other valves so that the incoming sea-water is not merely compressing any gases within -- that's the Q I want to see an answer to. Should be forthcoming within hours, I'd think. Luck to Nippon..
Post #340,527 by folkert 3/14/11 9:50:34 PM Reply	Well... okay, here goes. The reason they are in Full panic mode... is that even though they KNOW what to do and have practiced it a bah-million time, its for real this time. a Relevant but not close to scale case is this: The first time I had a REAL server down on my hands and I was 1500 miles away from (rather than 10 minutes driving), I was effectively nearly paralyzed with "How am I going to fix this?" The Latest one where a bad hard drive was swapped out (no problems there) and a new drive swapped in (lotsa problems there), caused SCSI bus errors all over the place... and then taking 4 hours to find the latent software bug... all in wanting to repair a Failed Drive in a mirrored array... Was calm and talking the whole way. Its a matter of being calm, cool, collected and well trained. That makes the big difference. Panic just doesn't make a situation good... anytime.

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