Japan Earthquake

Japan Earthquake | Page 2446

@dean hi dean, you asked me if there was an effect of the typhoon to the plants and i found something.
by Edano 10/3/2011 12:26:59 PM

@Edano We have some ORNL documents in the group library. Not sure if any are the one in question.

by lillymunster 10/3/2011 12:27:23 PM

nice find @ Edano,,, I'm reading posts to catch up
by dean 10/3/2011 12:27:25 PM

@ lilly. I put one of the ORNL documents in there that had some reference to the Browns Ferry designs
by dean 10/3/2011 12:28:00 PM

strangely, the typhoon affected radiation in torus B in #2. since #2 has an intact housing, so it might be coincidental.
by Edano 10/3/2011 12:28:44 PM

www.houseoffoust.com

check out the blue bubble curve. the light blue line is the typhoon. on sept 21.
by Edano via Houseoffoust 10/3/2011 12:29:25 PM

maybe they suspended water cooling during typhoon, and the torus radiation decreased, and increased again after the typhoon.
by Edano 10/3/2011 12:31:41 PM

it is hard to tell but certainly looks like something during that typhoon
by dean 10/3/2011 12:32:22 PM

@Edano, it's probably impossible to know exactly where the path of collected rain water leads in the building, I was just imagining it centrally locating as it poured into the building and then made it's way to the basement area
by dean 10/3/2011 12:34:41 PM

about the "water hammer incident" at san onofre: www.allbusiness.com
by Edano 10/3/2011 12:35:21 PM

efforts of the operator to take manual control in that ORNL report would not have been possible due to multiple outages of systems needed to activate the controls
by dean 10/3/2011 12:35:50 PM

Morning Dean! I was looking at the recent GE letter to NRC about seismic issues on control rods in BWR units. I found a long pattern of problems with cracking and boron loss in BWR control rods going back to at least 1979 with no solution that I can find.
by lillymunster 10/3/2011 12:35:55 PM

Dean, are pages of that manual you just posted supposed to be blacked out?
by lillymunster 10/3/2011 12:38:51 PM

Good morning, as to the hydrogen explosion, I think this is legalese saying it may not have been a hydrogen explosion that triggered the wetwell to burst at unit 2. That is all, and it does not exclude any other explosions or steam and pressure related breaches. I remember that the wetwells were retrofitted with spargers to prevent water hammer effects.
by Peter 10/3/2011 12:39:29 PM

@ Edano, in my career I have seen water hammer in systems, two common ways, failure of check valves to operate thus over pressurizing components, another one just as that is worse is steam hammer in a system
by dean 10/3/2011 12:39:40 PM

www.osti.gov try that one @ lilly.. it's strange, I opened my bookmark and it came through
by dean 10/3/2011 12:42:49 PM

"The most significant event involving check valve failures occurred on November 21, 1985, at the San Onofre Nuclear Generating Station, Unit 1. The failure of a feedwater pump discharge check valve to close led, in part, to the overpressurization and ultimate rupture of a flash evaporator shell. This failure, along with the concurrent failures of four additional feedwater system check valves to close led to the loss of inventory from all three steam generators, the partial voiding of feedwater piping within the containment building, and ultimately to a condensation-induced water hammer that extensively damaged the feedwater piping, pipe supports and snubbers, and two other valves. Despite these problems, operators were able to reestablish steam generator water levels and bring the plant to a stable cold shutdown condition. Inspections after the event revealed the condition of the failed check valves. Three of the valves were unable to close completely due to loosened internal parts. In the case of the other two failed valves, their disks had completely separated from their hinge arms, allowing full backflow to occur."

Source: www.allbusiness.com
by Edano 10/3/2011 12:43:05 PM

okay, but a torus rupture ? could that be possible ?
by Edano 10/3/2011 12:44:13 PM

The pressure balance between the containments is designed to be balance if I remember correctly, and they are low pressure systems, not designed to handle significant over pressure conditions. In the case of the steam venting to the torus by design and then overwhelming it by increasing pressure I can see that,, along with the fact of the EQ in failing the torus
by dean 10/3/2011 12:46:30 PM

@dean a powerpoint presentation of handling valves: www.google.de hope you can open it. better: docs.google.com
by Edano 10/3/2011 12:51:32 PM

if the steam is unquenched the pressure increases to potential failure point check this link @Edano and word search "quench", netfiles.uiuc.edu
by dean 10/3/2011 12:51:41 PM

I also could not rule out the potential for some form of hydrogen burn, perhaps not one that was involved in the bigger ones that led to the explosions, but smaller ones within perhaps the torus that could have caused an energy pulse and caused a breach
by dean 10/3/2011 1:01:33 PM

"the bwr mark 1 containments in the usa have undergone a variety of modifications since these inicial concerns were raised. among these were changes to the doughnut-shaped torus pressure suppression pool. steam being quenched from the primary vessel into the torus under high pressure would act as a rocket and could cause vessel displacement." netfiles.uiuc.edu page 17
damn
by Edano 10/3/2011 1:01:55 PM

www.tepco.co.jp check this out , after it opens page down 4 pages and notice the suggested RPV leak flow path into the torus
by dean 10/3/2011 1:03:59 PM

@ Edano, they have made modifications to the plants (well they said they did but not sure if all the utilities did it actually), the main thing is.. in the accident condition assumptions are made that involve.. HUMAN INTERVENTION to go along with the modifications... I suggest the NRC take one of the modified plants and pace it through the exact same scenario as fuku and see what the results are..
by dean 10/3/2011 1:06:10 PM