ScribbleLive

@all, I am going through my batch of TBS cam photos from Saturday looking for more details on #4 leaning etc. I think the tower for 3-4 may have a very small lean to the right, about a 2 degree lean.

travel safely Alblee

@dean - interesting to hear about that briefing -would be even more interesting to see the reports

yes UK they should release it and/or we can get it with FOIA

ty elaine.. checking now

Any bets on the new NRC report also being tagged as FOUO, so it's exempt from official release, will take weeks for someone like NYT to get a leaked copy?

Markfm... NRC has to report to Congressional hearing so we will be able to see it on c-span

@dean gosh! as the info mounts it's clear there was 1 prob after another. Must have been hell for those working there at the time

Elaine, control rods typically have whats called a worth curve which is an "S" shaped curve where the first movement of the rod is low in negative reactivity worth but with in the first 1/4 to 1/5 of the length of the safety rods is enough to stop the criticality and take it to sub critical

the safety rods drive up from the bottom in the BWR's and when they are withdrawn out of the core they typically compress a spring and have a clutch assembly which when released from the scram signal.. quickly drives the rods in the core in less than 4 seconds..

@dean and a stuck valve 'ver the first twelve hours pressure inside the containment structures increased steadily and led to venting from the suppression chamber via the dry containment to the service floor at the top of the reactor building, starting with unit 1 early on Saturday 12th, where pressure had reached twice the design level (over 750 kPa in PCV compared with 'maximum' 430 kPa - both gauge pressures).   This would damage pump seals and in addition the safety relief valve on the main steam line from the RPV in unit 1 stuck open. Inside unit 1 water levels dropped dramatically early on 12th, exposing fuel, and this was addressed by pumping seawater into the reactor pressure vessels (RPV) using external pumps brought to site, starting with unit 1 at 8.20 pm on 12th. This was apparently via the Low Pressure Coolant Injection System, connected into the RHR system'.   !!!!!http://www.world-nuclear.org/info/fukushima_accident_inf129.html>

@Veenie 4 does appear to be steaming.

Donner trying to dig up my design specs

Donner,,, I'm having trying to locate the accident analysis for the max vessel temp... the normal ops temp is around 550Degrees F,,,the trip level would be probably 125% above that and the design temp 150% above that however, even at the design temp it's not an instantaneous failure.. .and, there are other temp limits on the fuel which would probably be reaced first

one thing on the temps on the RPV analysis is the melting point of the carbon steel vessel

Donner.. I am going to post one of the analyses which I am using to try to estimate timelines to failure, it is assumed for a mark 1 reactor pressure vessel and talks of steel melting point
temps approx 1775 kelvin = 2735.33 degree Fahrenheit

'The central fuel storage on site near unit 4 has a pond about 12 x 29 metres, 11 m deep, with capacity of 3828 m3 and able to hold 6840 fuel assemblies. Its building is about 55 x 73 m. (There are 6375 assemblies in the undamaged central pool storage on site, with very low decay heat, and 408 in dry cask storage - utilized since 1995 for used fuel no longer needing much cooling.)'