Japan Earthquake

Japan Earthquake | Page 1440

that is fun making the temp plots: they have 21 sensors in there.
don't have so many different colors.....
by Edano edited by Edano 5/30/2011 10:28:16 AM

@Edano Molten nuclear fuel is extremely dense and has low viscosity. It doesn't leak like water. Takes a long time to sip through the holes and it can actually cool down enough at the bottom to prevent further fuel from leaking through. Also note that although meltdown has been confirmed (and they still don't know up to what extent), RPV breaches are still assumptions based on calculations and estimates, it is still not confirmed, however very likely. It's still a grey area. I wish we had more factual information.
by Pedro Jesus 5/30/2011 10:32:05 AM

@Pedro Jesus : but the holes will inevitably melt together in one big hole. i assume there is no bottom head anymore.
by Edano 5/30/2011 10:33:14 AM

@you : tepco says the holes were there in march. and now is may.
by Edano edited by Edano 5/30/2011 10:34:16 AM

@you : dean made a time chart of possible scenarios, and it shows: once there is a meltdown, the rest goes really fast.
by Edano 5/30/2011 10:36:42 AM

good morning to all
by dean 5/30/2011 10:37:01 AM

@Edano It is a possibility we cannot discard at the moment. But it wouldn't explain the high temperature at the control rods. When all the molten fuel sips through to the bottom of the containment vessel, it will be too far away from the control rods to cause such high temperatures [at the control rods], wouldn't you reckon?
by Pedro Jesus 5/30/2011 10:37:02 AM

@Pedro Jesus : the vapor ?
by Edano 5/30/2011 10:37:36 AM

@Edano And talking of the «devil» here he is. Hello Dean. We could use some expert input here. =)
by Pedro Jesus 5/30/2011 10:37:41 AM

vapor/steam
by Edano 5/30/2011 10:37:57 AM

hey Pedro.. how are you ... and Edano
by dean 5/30/2011 10:38:00 AM

@dean scared of unfounded rumors. ;)
by Edano 5/30/2011 10:38:48 AM

true Pedro
by dean 5/30/2011 10:39:47 AM

@Pedro.. is the topic melt through bottom head?
by dean 5/30/2011 10:40:35 AM

@dean : yes sir
by Edano 5/30/2011 10:41:02 AM

@dean What is your insight on this little detail we've been discussing? (Yes, we're discussing the high temperature reading at the control rod and what that might or might not tells regarding the current location of the molten fuel inside #2).
by Pedro Jesus 5/30/2011 10:41:41 AM

Hi @dean - in particular how robust are the sensors, and how likely to give wrong readings?
by hudebnik 5/30/2011 10:45:19 AM

@ Pedro, I'm not sure of the exact location of the temperature elements for the control rods which would make a difference due to elevation in the core. As far as fuel melt, it's like you said about it only being speculation to the exact amount and where it is or could have gone.. core melting means melting of control rods/safety rods and all the metal surrounding the fuel pellets like the tubing and fuel element framework.... and again,, depending on the quantity, that corium could be extremely high in temperatures and slump due to the shear weight and end up at the bottom head. I studied a report on the Browns Ferry reactor which had a major cable tray fire and resulted in similar conditions from station black out.. in that report they went through different scenarios and then analyzed times to cause failures in the bottom head... I"ll get that and post it..
by dean 5/30/2011 10:47:57 AM

the other argument is: tepco knows quite exactly what is happening, but since they don't tell us, i suspect the worst. they will not admit anything until it is obvious or it is good news.
by Edano 5/30/2011 10:49:05 AM

hudegnik... the system to monitor a safety significant parameter is robust and designed to environmental conditions but, the sensors in severe accident conditions leaves all things open.. over ranged in temp.. pressure,,, affects from seismic... etc.
by dean 5/30/2011 10:49:47 AM

@hudebnik @Pedro Jesus : i53.tinypic.com
by Edano via I53.tinypic 5/30/2011 10:50:57 AM

TMI could only estimate the fuel damage up to the point of taking the fuel out of the reactor.. then the were more accurate
by dean 5/30/2011 10:51:04 AM

@dean : here is your calculation: houseoffoust.com
by Edano 5/30/2011 10:52:36 AM

Note: Initial Condition Assumed at Reactor SCRAM + 10 minutes to Station Blackout
All times are in minutes.
SCRAM = Emergency shut down of a nuclear reactor.
HPCI = High Pressure Coolant Injection
RCIC = Reactor Core Isolation Cooling
SORV = Safety Operated Relief Valve
5/17/2011 ACCIDENT PROGRESSION IN MINUTES

Event Case 1 Case2 Case3
Station Blackout Station Blackout Station Blackout
No HPCI/RCIC Manual HPCI/RCIC Normal HPCI/RCIC
NO SORV Manual SORV Normal SORV
Core uncovered 17 337 315

Start core melt 57 396 388

Corium slumps to bottom head 78 453 419

RPV bottom head fails 142 543 515

Corium starts boil off of water @ concrete containment floor 142.5 543.5 515.5

Corium starts melting containment floor 162 544 580

Containment failure and leakage starts 185 596 601

Drywell and Wetwell electric penetrations start to leak at T=204C – 400F
Drywell and Wetwell electric penetrations decompose and blow out of containment at T=260C – 500

Table 1 Accident Progression Timeline
by Edano 5/30/2011 10:53:12 AM

@Edano Let's not forget that accidents such as this are very rare. There was the TMI in '78, the Chernobyl accident in '86 and this one at Fukushima. Apart from these, there have been only smaller scale problems on NPPs. There is not a lot of experience in dealing with this kind of situation. Therefore, I doubt that anyone at TEPCO knows exactly what is going on. They have to rely a lot on guessing and we have seen where that has lead them so far. There is no easy way out of this.
by Pedro Jesus 5/30/2011 10:53:56 AM

@Edano.. there were other cases that I looked at but to me the ones of interest concerned the status on the HPCI, RCIC and SORV's
by dean 5/30/2011 10:55:40 AM

worst case is loss of all those,,, and in analysis terms the reactor vessel boils off rapidly and vessel level decreases to uncover core... melt happens rapidly with slumping to the bottom head area... melting there begins at weakest points.. the electrical penetrations and then progresses to control rod penetrations...
by dean 5/30/2011 10:57:27 AM

Pedro.. at the lab in Idaho... there have been several small scale reactor experiments to study severe accidents.. and melts
by dean 5/30/2011 10:59:17 AM

@Pedro Jesus lets not forget that they have not "just been guessing" They have had data and information that they didnt want to release incase the "panic" the public................Information which was only released in the last 2 wks.............
by Angie 5/30/2011 11:00:17 AM

thing that makes it hard is one must assume every accident behaves the same and that's impossible to do... let alone human intervention that can through things out of control further .. like the operator who shut off emergency core cooling at unit 1
by dean 5/30/2011 11:01:06 AM

gm Angie
by dean 5/30/2011 11:01:09 AM

@dean Morning to you!!
by Angie 5/30/2011 11:01:47 AM

　Onagawa nuclear power plant was in the aftershock of April 07 remains one emergency generator does not work. Two of the three systems are disrupted power supply. One system and one generator is survived by a temporary fall on tightrope. translate.google.com
by elainekirk 5/30/2011 11:04:14 AM

This thing with R2 building and 99% humidity, can't use normal air filtering, Just use dehumidifiers, that will draw the airborne levels down as well as air filters.
by RBeaner 5/30/2011 11:07:32 AM

@Angie Having data is of no worth if you don't spend time analysing it. Raw data doesn't say anything about anything if released out of context. We shouldn't blame TEPCO for being cautious. We can blame them for being slow, though. But, yet again, I can only imagine the hardship those workers, engineers and technicians are going through in there. Let's not point the finger so hastily.
by Pedro Jesus 5/30/2011 11:08:57 AM

www.osti.gov this is an interesting read.. but have to put in right perspective for fukushima... it does show some times of melt, corium slump and bottom head interaction
by dean 5/30/2011 11:11:05 AM

hi elaine.. hi @dean did you see the flooding floor plans 5 & 6 are flooded too
by dean edited by elainekirk 5/30/2011 11:11:08 AM

good morning RBeaner
by dean 5/30/2011 11:12:13 AM

@dean morn all
by RBeaner 5/30/2011 11:13:02 AM

time for me to get a few things done today... will return... ty all PEACE...
by dean 5/30/2011 11:13:02 AM

@Pedro Jesus Oh they knew! You cant tell me they didnt............It was purely ass covering imop.........They are slow and incompetent! And I am talking about the Tepco big guys......the one and only people with the power to be able to release info, not the poor workers who have to deal with the stuff up.
by Angie 5/30/2011 11:15:01 AM

@Angie I have a different opinion, that's all. You can't tell me they knew either so lets keep at that. =)
by Pedro Jesus 5/30/2011 11:17:24 AM

@all Reviewing some old favorite links and alot no longer link back to story or document. I only saved links , not articles. Guess they are just gone now. Heads up!
by RBeaner 5/30/2011 11:17:24 AM