Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[NUCENG]

Yes, I was confused. Thank you for that.

So now another question: Does the containment system have an automatic pressure relief valve to vent the system through piping rather than the first point of failure? If so, why did the pressure rise to double the design limit? If there is no automatic pressure relief valve for the containment, why not?

I imagine a controlled relief of contaminated steam would almost always be preferable to an uncontrolled and irreversible containment failure.

Containment does not have any automatic venting provision. Thus it requires conscious operator action to vent containment, because in an accident the venting is releasing radioactivity to the environment and exposing the public. One of the reasons that installation of hardened vents was contoversial was that there was no design basis accident that ever required containment venting (hardened or otherwise) until the cleanup phase. In the end it was agreed to install the capability in all US Mk1 containments even though its only use would be for a severe accident (beyond the design basis).

I don't know if hydrogen explosions would have been prevented had Fukushima operators vented before exceeding the containment design pressure, but it couldn't have made it any worse. The loss of decay heat removal and fuel pool cooling would still have caused fuel damage, but maybe the roofs would still be in place.

 

[jlduh]

Containment does not have any automatic venting provision. Thus it requires conscious operator action to vent containment, because in an accident the venting is releasing radioactivity to the environment and exposing the public. One of the reasons that installation of hardened vents was contoversial was that there was no design basis accident that ever required containment venting (hardened or otherwise) until the cleanup phase. In the end it was agreed to install the capability in all US Mk1 containments even though its only use would be for a severe accident (beyond the design basis).

I don't know if hydrogen explosions would have been prevented had Fukushima operators vented before exceeding the containment design pressure, but it couldn't have made it any worse. The loss of decay heat removal and fuel pool cooling would still have caused fuel damage, but maybe the roofs would still be in place.

I think that it's oversimplified to say the roofs would still have been there, many other things would have been there i think... (of course I'm talking about the other reactors than just N°1).

Heavy damages to the structures and all the equipements around have considerably increased the difficulties for workers around to restore or contain the situation...

This venting mess (with all the problems that occurred on the vent system) is a good part of the current situation IMO. Not the initial cause of course.

 

[swl]

NHK TV News on 18May @ 21:00 JST:

Unit 2 has 99% humidity inside. It is thought that the humidity is coming from the spent fuel pool. TEPCO is planning to move up it's plan to improve cooling of the spent fuel pool. Four workers entered unit 2 today for 15 minutes. There efforts to inspect the facility were complicated by the high humidity. The highest radiation reading noted within unit 2 was 50 mSv/h. They also reiterated that TEPCO feels the torus was damaged in unit 2 by an explosion and that the unit has been leaking highly radioactive water since the explosion.

 

[zapperzero]

My question is this. Can anyone factually rule out that all or part of the reactor did not eject in the explosion on March 13th, and if it did what are the consequences globally of the fallout?

Let me rephrase first for clarity.

"1. Can anyone rule out the possibility that part of the core (by which I mean fuel rods, heavy metals such as uranium and plutonium) was ejected in the March 13th event?
2. If so, what parts of the world could be affected by fallout, and how?"

Now, on to the answers.

To your question 1: No. You should not, however, take this as an endorsement of your theory. It's simply that the matter is undecided. Multiple pieces of evidence (such as the evident absence of people dropping like flies on the plant grounds minutes after and continued work at the site) strongly suggest that it is, in fact, incorrect. Pictures from inside the reactor and chemical testing of the plant grounds and environs should settle the question.

To your question 2: What can be said with relative certainty is that the plume was nowhere near high enough to inject particulates (such as fine uranium and plutonium oxide dust) into the high-altitude currents. Such fallout would have been, thus, local and remain localized. Initial deposition would depend solely on local weather patterns on the day and in the subsequent week or so.

 

[ihatelies]

Let me rephrase first for clarity.

"1. Can anyone rule out the possibility that part of the core (by which I mean fuel rods, heavy metals such as uranium and plutonium) was ejected in the March 13th event?
2. If so, what parts of the world could be affected by fallout, and how?"

Now, on to the answers.

To your question 1: No. You should not, however, take this as an endorsement of your theory. It's simply that the matter is undecided. Multiple pieces of evidence (such as the evident absence of people dropping like flies on the plant grounds minutes after and continued work at the site) strongly suggest that it is, in fact, incorrect. Pictures from inside the reactor and chemical testing of the plant grounds and environs should settle the question.

To your question 2: What can be said with relative certainty is that the plume was nowhere near high enough to inject particulates (such as fine uranium and plutonium oxide dust) into the high-altitude currents. Such fallout would have been, thus, local and remain localized. Initial deposition would depend solely on local weather patterns on the day and in the subsequent week or so.

OK thanks for the response. Your rephrasing my question is not exactly what I meant.

I meant - did the plug, the containment cap, the nuclear fuel or the entire RPV eject in the explosion.

However, your rephrasing is the worst case scenario. Let's compare your answer to the evidence:

Answer 1: You say people didn't drop like flies immediately following the explosion, however I do recall that some employees did in fact die in that explosion and several more were seriously injured. I seem to recall 2-6 dead and 11 injured. I have not heard any updates on those early reports. Just a few days later, a couple of employees were "lost" and assumed dead as they were out reading radiation data. I think they were later found in or around the turbine buildings dead.

You also say work has continued on site. It did not immediately. They evacuated, and later information indicated that evacuation was prompted by a 12x increase in radiation in the control room.


On your answer 2: I certainly hope you are correct, but I've seen fully mixed opinions on this. I don't doubt that the initial smoke plume wasn't high enough to reach the jetstream, however that doesn't mean in any way the dust from that explosion couldn't have. Do you have data to support that these particles couldn't have circulated far from the plant? or is that your opinion.

What we do know is that shortly after the explosion, the USS Ronald Reagan encountered a "radioactive cloud" and a nuclear emergency was declared on the vessel, and they changed course. Early reports were that a helicopter and crew were exposed to slight radiation and they took showers and washed the helicopters down and all was well. Later reports detailed that the radiation monitors on the ship went ballistic, the ship went on nuclear emergency for three days, the air and water supply on the ship were contaminated, and they had near panic onboard.

Certainly the Reagan and her crew had the equipment and knowledgeable personel to determine exactly what the substances in that cloud were. I've not seen any data.

 

[ottomane]

IMO there are two alternative explanations for the vertical smoke plume and the energy released in the explosion:

1) The SFP went critical / exploded H2

2) Same with the RPV

Both of them are a mess and release huge amounts of radioactive particles. So, basically it does not matter if 1) or 2) happened.

 

[Rive]

IMO there are two alternative explanations for the vertical smoke plume and the energy released in the explosion:

1) The SFP went critical / exploded H2

2) Same with the RPV

Both of them are a mess and release huge amounts of radioactive particles. So, basically it does not matter if 1) or 2) happened.

Well, based on the missing heavy contamination of radioactive fuel particles and pieces all around the site there are two conclusions:
- none of those alternatives happened
- there must be other alternatives.

 

[ottomane]

Well, based on the missing heavy contamination of radioactive fuel particles and pieces all around the site there are two conclusions:
- none of those alternatives happened
- there must be other alternatives.

Not all fuel must have been ejected. And yes, in the days after the explosion they had to "bulldoze over" an area on the site because of some extreme radioactive material. And they found (at least) one piece of fuel 2 km away from the site.

What is your explanation for this?

 

[ihatelies]

IMO there are two alternative explanations for the vertical smoke plume and the energy released in the explosion:

1) The SFP went critical / exploded H2

2) Same with the RPV

Both of them are a mess and release huge amounts of radioactive particles. So, basically it does not matter if 1) or 2) happened.

This would be true if they contained exactly the same materials. As far as I've been able to understand they did not. Spent fuel contains some small percentage of plutonium molecules that have resulted from the fission process in the reactor. They are embedded in the fuel.

The reactor core of 3 contained the newly loaded MOX fuel, which as far as I know is made from finely ground (nanometer lever ground - finer than household dust) plutonium and uranium powders that are mixed and "sintered". What is unclear is whether the sintering process binds these materials permanently or are they simply pressed together and in the midst of an explosion they will return to the powder form. It's also unclear if the operating heat of 6 months in the reactor would bind them (I tend to think it would)

Certainly if a nanometer ground powder of even a heavy metal like plutonium were released it would be serious.

Of course if the spent fuel pools of either #3 or #4 contained new unused MOX rods, then I would think those are even more dangerous than the rods in the core, because I suspect the sintering process in manufacture does not tightly bind the powder.

 

[Rive]

Not all fuel must have been ejected. And yes, in the days after the explosion they had to "bulldoze over" an area on the site because of some extreme radioactive material. And they found (at least) one piece of fuel 2 km away from the site.

What is your explanation for this?

https://www.physicsforums.com/showpost.php?p=3304969&postcount=7484", and some earlier posts of that thread.

 

[SteveElbows]

Just a few days later, a couple of employees were "lost" and assumed dead as they were out reading radiation data. I think they were later found in or around the turbine buildings dead.

They were reported missing long before the explosions, and they are presumed to have been killed by the tsunami. If you go back and check early press releases about the nuclear emergency, mention of these missing workers turns up quite early, removing the possibility that they died much later during the explosive days.

I had hoped that your flawed and sloppy photo analysis had been put to rest days ago. Your analysis of the roof damage remains very poor, and I don't know what else to say about that since people already explained it to you days ago.

 

[Jorge Stolfi]

molten corium, of low thermal conductivity, mixes up with stuff, dilutes, the heat output decays, etc. ... low thermal conductivity, and freezes on contact.

Inuition gained from experience with ordinary molten metal and lava does not apply to corium.

If you dilute very hot molten metal with cooler molten stuff, such as concrete, it will immediatly cool down and remain cool. If you confine a ton of liquid metal in a closed container, it will stay there and slowly cool down. If you cool the surface of a lump of lava, it will form a solid, relatively cool crust and then slowly cool down throughout.

None of these "common sense facts" seem to apply to corium, because its radioactive contents will continue to generate heat from "nowhere" at the same total rate, no matter how much it is diluted or how it is confined. (Mixing with boron can prevent it becoming critical but has absolutely no effect on the decay heat generation.) If that heat has nowhere else to go, the corium will keep getting hotter and hotter until it boild away. (And even then the vaporized material will continue generating heat at the same rate.) If you dlute the corium 100 fold with molten concrete, and then keep that mass isolated, the rate at which its temperature increases with time will be reduced a 100 fold perhaps, but it will remain positive. So the entire mass --- original corium plus mixed concrete --- will continue to get hotter and hotter without limit; it will only take 3 months to reach the boiling point, instead of a day.

If the mass is not isolated but buried in soil or concrete (as in the "China syndrome" scenario), the temperature will tend to a limit when the heat produced inside the mass is equal to the heat lost to the medium. However, since concrete is a rather poor heat conductor, the equilibrium temperature inside may still be quite high --- as the lava example illustrates,

In this case dilution will help because it will increase the area available for heat to flow through into the cooler medium. An 8-fold dilution of the radioactive material will increase its surface area 4-fold; meaning that the temperature gradient at the surface (for the same total heat generation and dissipation) will be reduced to 1/4. However, since the radius of the mass is twice as large, the equilibrium temperature at the center should be reduced only by about one half. Now, if I read the posts correctly, the equilibrium temperature for an undiluted molten Fukushima fuel load is greater than 3000C. So it is not surprising that in Chernobyl the corium kept melting through several concrete floors, even though it was being diluted along the way.

I wonder if anyone has modeled the "China syndrome" scenario in more detail, namely how exactly the molten core would flow and get diluted once it gets surrounded by soil or concrete.

 

[ihatelies]

They were reported missing long before the explosions, and they are presumed to have been killed by the tsunami. If you go back and check early press releases about the nuclear emergency, mention of these missing workers turns up quite early, removing the possibility that they died much later during the explosive days.

I had hoped that your flawed and sloppy photo analysis had been put to rest days ago. Your analysis of the roof damage remains very poor, and I don't know what else to say about that since people already explained it to you days ago.

Steve pardon, but your analysis of my analysis is nonexistent, except for the fact that you say it's wrong.

So If you don't have anything scientific to add, I'd suggest you leave it to those who do.

 

[WhoWee]

https://www.physicsforums.com/showpost.php?p=3304969&postcount=7484", and some earlier posts of that thread.

Wasn't that de-bunked as re-bar a few thousand posts ago?

 

[ihatelies]

They were reported missing long before the explosions, and they are presumed to have been killed by the tsunami. If you go back and check early press releases about the nuclear emergency, mention of these missing workers turns up quite early, removing the possibility that they died much later during the explosive days.
.

They were not reported missing before the explosion. They were reported missing on March 16, the day after the explosion, and clearly the press release said they were missing due to the explosion.

http://www.theaustralian.com.au/news/breaking-news/cracked-roof-two-missing-workers-at-fukushima-reactor-no4/story-fn3dxity-1226022252864

They were found about two weeks later, dead because the lost blood and went into shock.

http://www.businessinsider.com/fukushima-two-missing-workers-found-dead-2011-4

There does seem to be an effort after the fact to say they were a victim of the Tsunami, not the explosion - wonder why?

 

[Rive]

Wasn't that de-bunked as re-bar a few thousand posts ago?

Please be more specific - which part do you think was debunked?

 

[zapperzero]

If the mass is not isolated but buried in soil or concrete (as in the "China syndrome" scenario), the temperature will tend to a limit when the heat produced inside the mass is equal to the heat lost to the medium. However, since concrete is a rather poor heat conductor, the equilibrium temperature inside may still be quite high --- as the lava example illustrates

It's not only heat loss through conduction because in the meantime the concrete is "burning". Lots of gases are produced which may carry some heat out. This might be enough to drop the temperature of the outer layer to something beneath the melting point of the corium and keep it there, forming a crust which after a time cracks, "fizzles" then solidifies again.

Also, in this real-life example, we also have some water that gets turned to steam, carrying even more heat away.

I'm saying, I guess, that the core may be moving downward much slower than you seem to imagine.

 

[WhoWee]

Please be more specific - which part do you think was debunked?

The metal objects covered by bulldozers was de-bunked to be re-bar - correct?

 

[SteveElbows]

They were not reported missing before the explosion. They were reported missing on March 16, the day after the explosion, and clearly the press release said they were missing due to the explosion.

Rubbish, I know for a fact that their status as missing persons was mentioned before any explosions. This is because I do actually have a suspicious mind myself, so I like to check the details, and I have already looked into this matter in the past. Unlike some people I am not so desperate to find a gloomy picture that I feel the need to be excessively sloppy or deliberately avoid evidence that contradicts my instincts, if I see reasonable evidence then I reduce my suspicions accordingly.

Here, very near the end of this document:

http://www.tepco.co.jp/en/press/corp-com/release/11031217-e.html

Further, there are 2 TEPCO employees whose presence has not been confirmed.

Regardless of the poor language, I am satisfied that they are talking about the two workers who were later found dead in turbine 4 building.

 

[clancy688]

Here's an interesting hypothesis regarding the spent fuel pools and explosions:

http://tec-sim.de/images/stories/fusfpfail.pdf

 

[Rive]

The metal objects covered by bulldozers was de-bunked to be re-bar - correct?

Nancy of Houseoffoust discussed some 'possible fuel rods' between U3 and U4 right after the explosions. Those were identified as I-beams from the roof later IIRC. If it's what you are thinking of then you are right, it was de-bunked.


Otherwise the NRC document mentions only 'very high dose material' bulldozed over without any further details. I can't recall any further (official) information. (Which does not means that there is nothing more about this, of course.) IMO this part is hardly important - there were the pieces of the previously used venting pipe, and there were the explosion itself. 'High dose material' could be anything, but what's more or less sure: it was not 'high dose' on 'Chernobyl scale', so they weren't (irradiated) fuel assemblies/rods/pieces.

 

[WhoWee]

Nancy of Houseoffoust discussed some 'possible fuel rods' between U3 and U4 right after the explosions. Those were identified as I-beams from the roof later IIRC. If it's what you are thinking of then you are right, it was de-bunked.

Yes, although I thought it was re-bar (not I-beams) - my mistake.

 

[zapperzero]

OK thanks for the response. Your rephrasing my question is not exactly what I meant.
I meant - did the plug, the containment cap, the nuclear fuel or the entire RPV eject in the explosion.

The RPV could not have ejected :rofl:. It's big. We would have seen it.

We would have seen the plug. Ditto for the cap. Huge, hot, radioactive things, can't miss them.

Please, try to get a grip on the dimensions involved. For all your doom-and-gloom outlook, you seem to be constantly underestimating things. For instance, you are confused about the amounts of radiation that would be given off if a significant fraction of the core were to be ejected.

We're NOT talking pieces radiating a piss-ant 0.9 Sv/h that you can bulldoze over and go on with your day. Your scenario implies white-hot (1000 at least, but probably closer to 3000 degrees Celsius) corium dust and droplets and drops and blobs and bits of low-power rods from the outside of the core that may be "only" 900 degrees or so. They would be burning anything they land on, starting masses of secondary fires. The bigger bits would be vaporizing and cracking and spalling under thermal stress, giving off doses in the tens/hundreds of Sievert per hour, not that anyone or anything could get close enough to do contact readings. In the meantime, the finer stuff would be falling and depositing on every surface, a powder deadly to inhale, radioactive enough to kill you in hours or days. You'd get a Sievert or two worth of gamma just from staring at the site or the plume from two kilometers away, like those poor curious fellows who stared into the burning reactor from a bridge in Pripyat.

Good thing anything like that didn't happen, eh? :rofl:

 

[Jorge Stolfi]

AFAIK, the space just below the reactor pressure vessel is densely packed with pipes, cables, and the hydraulic actuators of the conctrol rods. So any corium that breaches the RPV will have to melt through or flow around that mess before it reaches the concrete cap at the bottom of the drywell.

Could it be that the black smoke of #3 was caused by corium coming in contact with the hydraulic fluid of the actuators? The oil could have either burned inside the drywell, with whatever oxygen remained there, or it may have been vaporized and burned after escaping the drywell.

It seems that the steam emitted by #3 is leaking from the primary containment (into the refueling opening, and escaping from there through gaps around the service pool gates). The black smoke apparently came from the same area -- i.e. the service floor, as opposed from the lower levels. There seems to be little on the service floor that could burn.

 

[imandylite]

British Government interim report on the Fukushima accident:

http://www.hse.gov.uk/nuclear/fukushima/interim-report.pdf"

The report is a precursor to the expansion of UK nuclear plant facilities.

Much detail on the Fukushima accident and some interesting conclusions.

Conclusion 1: In considering the direct causes of the Fukushima accident we see no reason for curtailing the operation of nuclear power plants or other nuclear facilities in the UK. Once further work is completed any proposed improvements will be considered and implemented on a case by case basis, in line with our normal regulatory approach.

Conclusion 2: In response to the Fukushima accident, the UK nuclear power industry has reacted responsibly and appropriately displaying leadership for safety and a strong safety culture in its response to date.

Conclusion 3: The Government’s intention to take forward proposals to create the Office for Nuclear Regulation, with the post and responsibilities of the Chief Inspector in statute, should enhance confidence in the UK’s nuclear regulatory regime to more effectively face the challenges of the future.

Conclusion 4: To date, the consideration of the known circumstances of the Fukushima accident has not revealed any gaps in scope or depth of the Safety Assessment Principles for nuclear facilities in the UK.

Conclusion 5: Our considerations of the events in Japan, and the possible lessons for the UK, has not revealed any significant weaknesses in the UK nuclear licensing regime.

Conclusion 6: Flooding risks are unlikely to prevent construction of new nuclear power stations at potential development sites in the UK over the next few years. For sites with a flooding risk, detailed consideration may require changes to plant layout and the provision of particular protection against flooding.

Conclusion 7: There is no need to change the present siting strategies for new nuclear power stations in the UK.

Conclusion 8: There is no reason to depart from a multi-plant site concept given the design measures in new reactors being considered for deployment in the UK and adequate demonstration in design and operational safety cases.

Conclusion 9: The UK’s gas-cooled reactors have lower power densities and larger thermal capacities than water cooled reactors which with natural cooling capabilities give longer timescales for remedial action. Additionally, they have a lesser need for venting on loss of cooling and do not produce concentrations of hydrogen from fuel cladding overheating.

Conclusion 10: There is no evidence to suggest that the presence of MOX fuel in Reactor Unit 3 significantly contributed to the health impact of the accident on or off the site.

Conclusion 11: With more information there is likely to be considerable scope for lessons to be learned about human behaviour in severe accident conditions that will be useful in enhancing contingency arrangements and training in the UK for such events.

 

[etudiant]

It would seem that there is a general agreement that all three reactors have had their fuel melted.
Presumably this means that all volatiles in the reactor fuel have been expelled.
What does this translate to, in objective terms?
The initial estimates were for about 10**17 bequerels from iodine alone. These estimates were made before there was any thought that all 3 reactors had gone bust.
Are there any new estimates that can now be made?

 

[ihatelies]

The RPV could not have ejected :rofl:. It's big. We would have seen it.

We would have seen the plug. Ditto for the cap. Huge, hot, radioactive things, can't miss them.

Please, try to get a grip on the dimensions involved. For all your doom-and-gloom outlook, you seem to be constantly underestimating things. For instance, you are confused about the amounts of radiation that would be given off if a significant fraction of the core were to be ejected.

We're NOT talking pieces radiating a piss-ant 0.9 Sv/h that you can bulldoze over and go on with your day. Your scenario implies white-hot (1000 at least, but probably closer to 3000 degrees Celsius) corium dust and droplets and drops and blobs and bits of low-power rods from the outside of the core that may be "only" 900 degrees or so. They would be burning anything they land on, starting masses of secondary fires. The bigger bits would be vaporizing and cracking and spalling under thermal stress, giving off doses in the tens/hundreds of Sievert per hour, not that anyone or anything could get close enough to do contact readings. In the meantime, the finer stuff would be falling and depositing on every surface, a powder deadly to inhale, radioactive enough to kill you in hours or days. You'd get a Sievert or two worth of gamma just from staring at the site or the plume from two kilometers away, like those poor curious fellows who stared into the burning reactor from a bridge in Pripyat.

Good thing anything like that didn't happen, eh? :rofl:

You assume I think that a nuclear explosion occurred. I did not say that.

I know exactly the size of the things that I'm talking about. So please stick to the facts, instead of the commentary.

If you can prove me wrong I will shut up.

First tell me what went through the hole.

Second tell me what has been burning in "masses of secondary fires" for eight weeks on the northwest corner of the #3 reactor building wreckage.

Third, tell me how the spent fuel pool - if that's where the explosion occurred, could have blown up the rest of the building, without destroying itself.

Facts:
1. something very big and round went through the roof right above the reactor core location.

2. Something has been burning on the northwest corner of the building for weeks, rendering that area a charred mess, with big holes going at least into the basement.

3. Tepco said for weeks the pressure vessel was intact and gave temp and pressure readings, which all must have been fabricated, since they now admit the fuel has probably melted through the RPV.

4. Some people did die in the explosion - possibly just as you have described - Internal bleeding and shock - like.


I'm not familiar with where you get your knowledge of exactly what would happen in an explosion scenario - as far as I know it's never happened before like this - so your speculation and detailed description is simply that - speculation.

I'm not a doomsdayer. I'm a realist. I'm happy to be proven wrong, but the facts support what I'm saying, no matter how much you wish they didn't.

 

[ihatelies]

Here's an interesting hypothesis regarding the spent fuel pools and explosions:

http://tec-sim.de/images/stories/fusfpfail.pdf

Interesting analysis, but the fatal flaw is an assumptive jump between the pages quoted below.

4) Basic facts are that there do not exist many potential sources of explosion or pressure surge in a nuclear reactor.
The most important hazard is hydrogen production: hydrogen can be produced either in the reactor pressure vessel (RPV) or in the spend fuel pool. As long as the containment does not fail, no hydrogen from the RPV can escape into the reactor building. A hydrogen explosion can be a detonation characterized by a shock wave or a deflagration characterized by a somewhat smoother pressure surge. Another source of explosion can be a rapid evaporation, when water comes into contact with hot structures, e.g. reflooding of some overheated fuel elements. The most dangerous source of explosion is a restart of the chain reaction, but this can be ruled out by basic physics.

So, the hydrogen has to come from the spent fuel ponds. Hydrogen in the spent fuel pond can be produced by the zircon-steam-reaction which is a strong exothermic reaction and starts when the fuel elements are not cooled properly and heat up to temperature above 1500°C.

In the first paragraph he says there are two possible sources for hydrogen, then in the second he jumps the spent fuel as being the cause.

Presumably because he makes the assumption the containment was not breached so it couldn't be the RPV, but we now know the containment has been breached on 1,2 and 3.

So that jump cannot be made.

Seems like the same jump that several here have incorrectly made.

 

[SteveElbows]

I'm not a doomsdayer. I'm a realist. I'm happy to be proven wrong, but the facts support what I'm saying, no matter how much you wish they didn't.

Rubbish. You are not at all happy to be proven wrong, to the extent that you ignore evidence presented here and end up winding up people like me as a result.

For example in your last post you talk as if rpv temperatures are a fabrication. What are you basing that on? An what's this rubbish you are talking about uncontrolled fires raging for weeks at north of building?

Furthermore, you complain that I did not sensibly analyse your stupid 'round holes in roof' stuff. In fact I told you that those areas do not appear round from the other angles for which we have photographs available, but you just ignore that because it does not fit your theories, theories which you are clearly well attached to despite a lack of evidence.

 

[zapperzero]

Could it be that the black smoke of #3 was caused by corium coming in contact with the hydraulic fluid of the actuators?

Could be anything, but there's relatively little fluid. Could be metal, could be carbon from the seals, could be concrete that's burning. Tepco should have flown something through the plume and gotten samples, but perhaps they were busy with other things.

 

[pdObq]

I wonder if anyone has modeled the "China syndrome" scenario in more detail, namely how exactly the molten core would flow and get diluted once it gets surrounded by soil or concrete.

I'm saying, I guess, that the core may be moving downward much slower than you seem to imagine.

You might want to check out this document: http://www.ornl.gov/info/reports/1981/3445600211884.pdf . It's a simulation and analysis of station blackout scenarios at Browns Ferry unit 1 from 1982.

Lots of plots of various reactor parameters (pressures, temps, hydrogen production, etc) versus time after LOCA for lots of accident and operator action scenarios.

Attached is a snapshot of a plot showing drywell concrete penetration versus time (p.145). I think it's much faster than one would imagine -- 7m in about 6 hours :uhh: .

Credit for finding that document goes to Jim Hardy afaik, https://www.physicsforums.com/showthread.php?p=3299953#post3299953 (see also https://www.physicsforums.com/showthread.php?p=3304173#post3304173 ).

NUCENG found another such study for Browns Ferry from 1985 that is more condensed (by a factor 10...), but the plots look qualitatively very similar and so are the timescales, http://www.osti.gov/bridge/servlets/purl/6402578-Rr9xTe/6402578.pdf . See his post https://www.physicsforums.com/showthread.php?p=3304320#post3304320.

 

[ihatelies]

Rubbish. You are not at all happy to be proven wrong, to the extent that you ignore evidence presented here and end up winding up people like me as a result.

Seems to me you don't have much information on my happiness or not. I'll admit, I don't bowl over to personal attacks easily.

For example in your last post you talk as if rpv temperatures are a fabrication. What are you basing that on? An what's this rubbish you are talking about uncontrolled fires raging for weeks at north of building?

If the fuel melted and the RPV breached early on, as they have admitted in #1, then yes the temps and pressures they've been issuing for weeks do seem pretty suspect, don't they?

As far as the fires. Look at the pictures. Look at where the smoke has been emanating for weeks. Look at where they have been pumping water from fire trucks.

Furthermore, you complain that I did not sensibly analyse your stupid 'round holes in roof' stuff. In fact I told you that those areas do not appear round from the other angles for which we have photographs available, but you just ignore that because it does not fit your theories, theories which you are clearly well attached to despite a lack of evidence.

OK, because a round hole doesn't look round from another view means it doesn't exist - right? Do you really mean to say that?

Last time, you said you couldn't find the holes, but you vehemently argued with me about it, then when I posted this picture of it you then said "oh I saw that all along, but didn't know what you're talking about.

And maybe it's just you calling my analysis stupid and wild, without any facts to refute - or at least anything logical, that makes me discount your opinion somewhat.

 

[pdObq]

I meant - did the plug, the containment cap, the nuclear fuel or the entire RPV eject in the explosion.

The RPV could not have ejected :rofl:. It's big. We would have seen it.

Well, I don't want to get into that battlefield, but the thought of the RPV launching like a steam rocket is just hilarious :rofl:.
The holes in the bottom for the control rods would make great nozzles, too. And the steam and water nozzles would be great for steering. Oh my :rofl:.

Sorry, if your intention was more like "all the contents of the RPV were ejected". (BTW there is also the big heavy steam dryer and separator assembly in the way between the core and the RPV head cap.)

Anyway, would you guys mind settling this outside, i.e. in a new thread or via PMs ?

 

[zapperzero]

You assume I think that a nuclear explosion occurred. I did not say that.
I know exactly the size of the things that I'm talking about.

You have no idea, and no wish to learn. I did not say anything about a nuclear explosion. That's a straw man you set up all by yourself.

I am talking about the aftermath of ANY kind of event that could have dumped core all over the countryside. You wish to posit that the Gojira stuck a pipe into the bottom of the RPV and blew out some molten uranium like a spolied brat with a slurpee? Fine. Same result.

This is getting tiresome, really. Especially the part where you repeatedly fail to understand just how deadly that fuel is. No-one could be working on site. No-one could go there unprotected and survive. No, Tyvek overalls do not count.

The situation is bad enough as it is, no need to imagine things.

 

[zapperzero]

Anyway, would you guys mind settling this outside, i.e. in a new thread or via PMs ?

I'm just about done with this. I wouldn't mind, either way.