Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Astronuc]

So, I was hoping someone could give me a clear answer on this because I've been unable to do so. How fast does this radiation dilute in air? Over the course of several kms what type of concentration loss occurs?

It depends on a number of factors such as temperature (molecular diffusion), wind speed and turbulence (mixing), among various meterological conditions. Rain can wash nuclides out of the air, but then deposit on land, where they enter the soil, plant life or animal life, or diluted in water and transported by flow water.

This is in addition to the decay of the particular nuclides being transported.

I'll see if I can dig up a reference on plume dispersal.

 

[OmCheeto]

That's what I really want to see - the Cis of various nuclides.

Thank you for keeping up with all this Astro.

 

[Angry Citizen]

Angry,

Look at it this way, a more perfect environment could not be had to probe your areas of concern, radiation hardness, no ?

Rhody...

Believe me, I'm on your side in this. I'd love some more information. Much of the hysteria surrounding this incident is based on lack of knowledge. And I mean that both maliciously and non-maliciously. There is terrible ignorance of the dangers (much of which is invented) of nuclear power in the vast majority of individuals (maliciously), and those who could interpret details with their vast knowledge lack the information to do so (non-maliciously). An example of the latter is Astronuc here: Just imagine what he could tell us if he knew the details inside the plant right now. All this speculation about corium would go away quick, fast, and in a hurry.

 

[rhody]

Believe me, I'm on your side in this. I'd love some more information. Much of the hysteria surrounding this incident is based on lack of knowledge. And I mean that both maliciously and non-maliciously. There is terrible ignorance of the dangers (much of which is invented) of nuclear power in the vast majority of individuals (maliciously), and those who could interpret details with their vast knowledge lack the information to do so (non-maliciously). An example of the latter is Astronuc here: Just imagine what he could tell us if he knew the details inside the plant right now. All this speculation about corium would go away quick, fast, and in a hurry.

Angry,

If you haven't already done so I recommend you take the time to read the link on Chernobyl https://www.physicsforums.com/showpost.php?p=3195716&postcount=450".
It paints a sobering picture of what mistakes were made, and action taken to control the radiation after the event. As to your last comment, I agree, accurate information regarding the reactor's state is critical (no pun intended, well maybe just a little) to assess what steps need to be taken. The hard part is time is not on our side, nor is there any room for error.

Rhody...

 

[Angry Citizen]

I've read about Chernobyl extensively. Nothing in this disaster seems to approach Chernobyl's magnitude. I'm not a nuclear engineer, but I can tell you that the dispersal of contaminants is much different in this situation. For one, it doesn't appear as though anything from within the core has caught fire. I believe any smoke (note: not steam) rising from the destroyed buildings has been from a building fire. This released some contaminants from the gas venting that would otherwise have stayed within the units, but again, nothing like Chernobyl.

For another, all but one of the containment units appear intact, and the other one is either intact as well, or merely cracked. This last one is bad, but again, it's nothing like the explosive destructive power seen in Chernobyl which released solid contaminants into aerosol form. The key here is where the hydrogen explosion occurred. At Chernobyl, it occurred within the core, which as you know would send contaminants airborne. At Fukushima, it occurred outside the core, which would tend to compact the contaminants, though dispersal into aerosol form is still an obvious fact. The difference again is that the only source of these contaminants is from the gas venting, which would contain a certain level of caesium and other solid contaminants, but nothing on the level of a full core breach.

Finally, there was a release of corium at Chernobyl. No such corium is known to be outside the reactors at Fukushima. Inside the core we can only speculate, but it seems likely that there's corium in all three damaged reactors, even if it's only a small amount (EDIT: I made a terrible mistake and put 'at the bottom of' -- please disregard that).

The wildcard here is the spent fuel ponds. From what Astronuc has been telling us, a spent fuel meltdown hasn't been studied extensively. This is the only possible way Fukushima could become another Chernobyl. Sadly, what I know about spent fuel ponds pales in comparison to what I know about nuclear reactors. Again I'll stress that I'm not Astronuc. I'm not a nuclear engineer. This is simply what I can glean from his testimony, from my own (layman's) knowledge of nuclear reactors, and from what I know about aerodynamics and particle dispersal patterns (my knowledge of which will probably increase exponentially in the next couple years -- I'm an aerospace engineering student). So please, take my statements with a grain of salt -- or a pillar of it.

Edit: I've never heard of Cherenkov radiation. At least I got something new from the article. God it's beautiful.

 

[Reno Deano]

From NEI today:

No Radiation Levels of Concern in Western U.S.

The U.S. Department of Energy and Environmental Protection Agency on Friday issued a joint statement to confirm that the nationwide network of sensitive radiation monitoring equipment has detected no radiation levels of concern to U.S. citizens.

The EPA's RadNet system notifies scientists in near real-time of elevated levels of radiation to enable them to determine whether protective actions are required. DOE's IMS (International Monitoring System) operates as part of the Comprehensive Nuclear Test Ban Treaty and detects tiny quantities of radiation that may indicate an underground nuclear explosion anywhere in the world.

One of the DOE monitors in Sacramento, Calif., detected tiny quantities of a radioisotope (xenon-133). The level of the isotope detected would result in one-millionth of the dose rate that a person would normally receive from natural background sources.

More information is available at www.epa.gov/radiation[/url] or http://nei.cachefly.net/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region/

[I]Authors Note: I think this is bad info on Xe-133, even though they did not directly associate it with the Japanese reactor crisis. Xe-133 shorter half-life than I-131, and is used in and around most major cities in hospitals and industrial complexes. Whomever wrote the last paragraph was not very knowledgeable in communicating radiation dose facts.[/I]

 

[Astronuc]

The wildcard here is the spent fuel ponds. From what Astronuc has been telling us, a spent fuel meltdown hasn't been studied extensively. This is the only possible way Fukushima could become another Chernobyl. Sadly, what I know about spent fuel ponds pales in comparison to what I know about nuclear reactors. Again I'll stress that I'm not Astronuc. I'm not a nuclear engineer. This is simply what I can glean from his testimony, from my own (layman's) knowledge of nuclear reactors, and from what I know about aerodynamics and particle dispersal patterns (my knowledge of which will probably increase exponentially in the next couple years -- I'm an aerospace engineering student). So please, take my statements with a grain of salt -- or a pillar of it.

I'll have to try to dig up research on corium and severe accidents.

Having hot Zr-2 and Zr-4 in air is common practice in the manufacturing process. Red hot ingots are hot worked into logs and subsequently billets. It oxidizes, but it doesn't burn.

http://www.wahchang.com/pages/products/data/pdf/Zirconium Production Flow Chart.pdf (use 'save target as')

 

[BHamilton]

More BOTE calculations, which I'll do on the fly...

Comments please?

You seem to have mixed up the measurements and your model's predictions in your last post...

With a model of I ~ I0 (x0/x)^2 exp(-mu*(x-x0)) and two points (100 meters, 4.13 mSv/hr, 300 meters, 87.7 mSv/hr) and one degree of freedom (mu), one can directly find the mu that fits the data (mu = ln(I1*x1*x1/I0*x0*x0)/(x1-x0) and you find mu = 0.0043 m^-1.

Going back and using this to find the value at 20 meters, we find on the order of 3 Sv/hr. Closer than that I wouldn't trust the model, since even at that distance we're already likely outside the region of validity of the model (which assumes the source is small compared to the distance we're measuring at, once we hit sizes of the same order of magnitude as the reactor buildings bets are off here). A safer prediction would be the value we find at 50m, which is like 430 mSv/hr

Dr. Michio Kaku ...

Is currently speaking on CNN live. If you can get a later video replay of it, it is a must see...especially as he speaks about the Japanese leaders (Gov't and TEPCO) being out of touch with reality.

This is a very serious situation of course, but I find the idea of Michio Kaku accusing anyone else of being out of touch with reality hilarious

 

[vanesch]

Basically, the responsible engineer and staff disabled the protection systems. They performed an experiment, but the parameters of the core were not in accordance with the plan (I need to go back and review the sequence). They removed a control element, and then got a + reactivity feedback due to an unanticipated source (the part I for which I need to refresh my memory). When that happened, they naturally reinserted the control elements. Now, in a graphite-moderated core, water (which is normally a moderator in an LWR) is actually a neutron poison. When the tip (not an absorber) of the control rod was inserted, it displaced the water, which removed the -reactivity, or otherwise inserted more + reactivity - and boom - the neutron multiplication took off - very quickly.

Yes, that's right, especially because the tip of the bars were made of graphite, which is a better moderator than the water it displaced.

The other problem was that, due to an unforeseen power request, one had trottled up the reactor during the day before (which had been brought to low power for a day to do the experiment), and when the power request was over (I think around 11 PM), they *brutally* reduced the power of the reactor again to the "experimental level", creating a Xe-poisoning.

This Xe-poisoning tended to stop the reactor all together, and because the night crew wanted to do this experiment at all cost, they removed control rods much further away than normally allowed to keep it "live" and avoid stopping the chain reaction.

So essentially the control of the reactor was not with the rods anymore, but with the Xenon. Which is an extremely unstable situation.

 

[AntonL]

Referring to the latest http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf"

Holes have now been cut into the roofs of reactor building 5 and 6 so that hydrogen can vent and diminish possibility of an explosion.

That reactor 4 is still classed as a INES level 3 Serious Incident is a gross understatement.

Pressure readings are published for unit 1, 2 and 3
what do you make of them?

 

[M. Bachmeier]

You seem to have mixed up the measurements and your model's predictions in your last post...

With a model of I ~ I0 (x0/x)^2 exp(-mu*(x-x0)) and two points (100 meters, 4.13 mSv/hr, 300 meters, 87.7 mSv/hr) and one degree of freedom (mu), one can directly find the mu that fits the data (mu = ln(I1*x1*x1/I0*x0*x0)/(x1-x0) and you find mu = 0.0043 m^-1.

Going back and using this to find the value at 20 meters, we find on the order of 3 Sv/hr. Closer than that I wouldn't trust the model, since even at that distance we're already likely outside the region of validity of the model (which assumes the source is small compared to the distance we're measuring at, once we hit sizes of the same order of magnitude as the reactor buildings bets are off here). A safer prediction would be the value we find at 50m, which is like 430 mSv/hr



This is a very serious situation of course, but I find the idea of Michio Kaku accusing anyone else of being out of touch with reality hilarious

This is the second video... http://www.cnn.com/video/#/video/be....japan.nuclear.chernobyl.cnn?iref=videosearch

In his earlier video he was speaking hypothetically. Unless he is now in possession of information most everyone else doesn't have, he has made a very large jump into a conclusion.

 

[Andrew Mason]

A tip of the hat to the posters on this thread, particularly Astronuc. (Astronuc, are you getting any sleep?). The information is much appreciated. Have you seen the no. of views: over 58,000 so far in one week! That must be close to a record.

AM

 

[Reno Deano]

Prof. Kaku's argument is sound on the premise of preparing for a worst case situation. Since Chernobyl was a remote site, entombment was an easy option. I think Japan will wait to see if restored power will let them get a better hand on the situation. If the seawater injection has worked and re-flooding the spent fuel pools is carried out, then only a lengthy core stabilization, facility clean up and decommissioning is left. Oh, and the compilation of a lessons learned report that will fill a Harvard size library.

 

[AntonL]

Possible cause of hydrogen explosion of reactors 1 and 3 is published by http://allthingsnuclear.org/post/3940804083/possible-cause-of-reactor-building-explosions" - an excellent article

What bothers me is quote "A little-known test performed decades ago at the Brunswick nuclear plant in North Carolina may hold the key to answering that question." - why little-known - this is a design limitation/fault common to many nuclear power stations. If this had been common knowledge in the nuke industry safety manuals and emergency procedures may have been rewritten - I am sure they are now being re-drafted.

Now at Fukushima containment vessel pressure has been http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf" *1) to be steady at .140 to .150 MPa_abs [STRIKE]which is about the same as 70PSI Gauge[/STRIKE]. Now reactor vessels 2 and 3 are reported near 0 pressure Guage that is the pressure inside the the reactor vessel is the same as the pressure in the containment vessel leading to the conclusion that the reactor vessel is breached [STRIKE]and the containment vessel 'auto-vents' as described in the article[/STRIKE].

It is also reported that sea water flooding into the reactor cores is taking place continually one of two things can happen
1- worst case it boils of and steam is vented as above then slowly a massive NaCl crust must be developing
2- best case the reactors have cooled and the containment vessel slowly filling with water

*1) Reactor 3 CV pressure 0.045MPa_abs must be a typo as it is a vacuum and I think should read as 0.145MPa_abs as in previous reports

Edit: As pointed out later pressure conversion is wrong hence wrong part struck out

 

[AtomicWombat]

You seem to have mixed up the measurements and your model's predictions in your last post...

With a model of I ~ I0 (x0/x)^2 exp(-mu*(x-x0)) and two points (100 meters, 4.13 mSv/hr, 300 meters, 87.7 mSv/hr) and one degree of freedom (mu), one can directly find the mu that fits the data (mu = ln(I1*x1*x1/I0*x0*x0)/(x1-x0) and you find mu = 0.0043 m^-1.

Going back and using this to find the value at 20 meters, we find on the order of 3 Sv/hr. Closer than that I wouldn't trust the model, since even at that distance we're already likely outside the region of validity of the model (which assumes the source is small compared to the distance we're measuring at, once we hit sizes of the same order of magnitude as the reactor buildings bets are off here). A safer prediction would be the value we find at 50m, which is like 430 mSv/hr.

BHamilton, the point of my calculation was not to accurately model the radiation, but to show using two actual measurements at known heights that current radiation measurements do not rule out the possibility that the lava-like discharge from building 4 is coria.

The Chernobyl measurements were taken at a human scale, in the vicinity of the reactor core and close to fuel fragments.

Estimating the attenuation coefficient using these two measurements assumes gamma rays of only one energy are being measured as attenuation in air increases with gamma ray energy. (So no this is not a one parameter problem.) Furthermore we do not know where these measurements were made, only the height at which they were made, so the actual distance to the hypothetical source cannot be estimated.

I freely admit the model is flawed. It could hardly be otherwise. Almost certainly there are multiple sources of radiation on the site, including lofted radionucleotides. As I said my purpose was to determine if the radiation measurements made from the air rule out exposed coria. They do not.

 

[AtomicWombat]

Prof. Kaku's argument is sound on the premise of preparing for a worst case situation. Since Chernobyl was a remote site, entombment was an easy option. I think Japan will wait to see if restored power will let them get a better hand on the situation. If the seawater injection has worked and re-flooding the spent fuel pools is carried out, then only a lengthy core stabilization, facility clean up and decommissioning is left. Oh, and the compilation of a lessons learned report that will fill a Harvard size library.

"If this spirals out of control we could use a good chunk of northern Japan", Michio Kaku

I assume this is hyperbole. I can't see it being worse than a long-term 30 km (or so) exclusion zone.

On the other hand I think his comments about the Japanese leadership loosing touch with reality are accurate.

I was disappointed about what he didn't say. There is an urgent need for much better assessment of the true state of the reactors and SFPs. I read http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA335076&Location=U2&doc=GetTRDoc.pdf" and it was clear that for some time the operators were working on the false assumption that the reactor was still intact. Too often I hear from Japan, "we think this", "we think that", "this glint of light means the SFP has water in it", etc.

TEPCO & the Japanese government seem to be flying blind and their actions on the ground reinforce this impression.

 

[mattm2]

Possible cause of hydrogen explosion of reactors 1 and 3 is published by http://allthingsnuclear.org/post/3940804083/possible-cause-of-reactor-building-explosions" - an excellent article

What bothers me is quote "A little-known test performed decades ago at the Brunswick nuclear plant in North Carolina may hold the key to answering that question." - why little-known - this is a design limitation/fault common to many nuclear power stations. If this had been common knowledge in the nuke industry safety manuals and emergency procedures may have been rewritten - I am sure they are now being re-drafted.

Now at Fukushima containment vessel pressure has been http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf" *1) to be steady at .140 to .150 MPa_abs which is about the same as 70PSI Gauge. Now reactor vessels 2 and 3 are reported near 0 pressure Guage that is the pressure inside the the reactor vessel is the same as the pressure in the containment vessel leading to the conclusion that the reactor vessel is breached and the containment vessel 'auto-vents' as described in the article.

It is also reported that sea water flooding into the reactor cores is taking place continually one of two things can happen
1- worst case it boils of and steam is vented as above then slowly a massive NaCl crust must be developing
2- best case the reactors have cooled and the containment vessel slowly filling with water

*1) Reactor 3 CV pressure 0.045MPa_abs must be a typo as it is a vacuum and I think should read as 0.145MPa_abs as in previous reports

If there is little/no pressure in reactor core 2 and 3 and; if, water is being fed into those cores and; if the core is breached: would not there be a massive amount of steam generated? Water under no pressure turns to steam easier than with pressure added. How fast does water go into the core? There is no steam coming from number 2 is there? Have they released the results of the IR temperature readings taken by aircraft and/or sat?

 

[AntonL]

Off Topic: Fishing boat and tsunami wave

Off topic: Fishing boat powers through tsunami wave http://www.youtube.com/watch?v=3fqyOpqnJyw&feature=player_embedded"

 

[daumphys]

How about this equation?

rate equation

-Q_out + Q_generated = Q_accumulated
Q_out = U A (del T)_log_system_min

The Problem is Q_accumulated value, it makes temperature increasing.

Normal reactor pump cooling U=high, A=high, (del T)_log_system_min = low(high pressure)
Accident recover cooling U= low, A=low, (del T)_log_system_min = high(atmosphere)

Increasing A is God's will.

If Q_generated is not too high, accident recovery cooling method might give some effect.

 

[Astronuc]

What bothers me is quote "A little-known test performed decades ago at the Brunswick nuclear plant in North Carolina may hold the key to answering that question." - why little-known - this is a design limitation/fault common to many nuclear power stations. If this had been common knowledge in the nuke industry safety manuals and emergency procedures may have been rewritten - I am sure they are now being re-drafted.

I suspect the utility and GE understood the results, and that it exceeded the design requirement. If it was successful, then it is probably little known, because a success is not a concer.

Now at Fukushima containment vessel pressure has been http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf" *1) to be steady at .140 to .150 MPa_abs which is about the same as 70PSI Gauge. Now reactor vessels 2 and 3 are reported near 0 pressure Guage that is the pressure inside the the reactor vessel is the same as the pressure in the containment vessel leading to the conclusion that the reactor vessel is breached and the containment vessel 'auto-vents' as described in the article.

*1) Reactor 3 CV pressure 0.045MPa_abs must be a typo as it is a vacuum and I think should read as 0.145MPa_abs as in previous reports

Let's be careful with conversion factors. One (1) atm = 14.696 psi = 0.101325 MPa, so 0.14 MPa = 20.3 psi, and 0.15 MPa = 21.76 psi. 0.1 MPa = 14.50377 psi.

Earlier numbers reported in the media were a design presure of 0.4 MPa (58 psi), which is less than 0.4274 MPa (62 psi), but higher pressurizations of up to 0.84 MPa (122 psi) in unit 1 before the H-explosion.

One must also be careful in differentiating betwee absolute, gage and differential pressures. The media is not so careful, and some professionals sometime misstate.

It is also reported that sea water flooding into the reactor cores is taking place continually one of two things can happen
1- worst case it boils of and steam is vented as above then slowly a massive NaCl crust must be developing
2- best case the reactors have cooled and the containment vessel slowly filling with water

The deposition of salt is of interest. The best case now is to have the RPV filled with water. I expect that containment is flooded to the extent possible.

 

[AntonL]

Let's be careful with conversion factors. One (1) atm = 14.696 psi = 0.101325 MPa, so 0.14 MPa = 20.3 psi, and 0.15 MPa = 21.76 psi. 0.1 MPa = 14.50377 psi.

Appologies - I made a mistake in the conversion I will edit the original post

 

[TCups]

It would be interesting to see some high res satellite imagery of the FK site in the IR and XRay spectral ranges. Surely there must be some that have the capability that could be tasked to obtain them. Anyone know of any source for high res imagery of this source that might be accessible to the public? Or are they all "classified" or otherwise restricted by the DOD?

The "official news this AM seems to be "No news" -- perhaps a good thing.

Here's Digital Globe Image (from another website) -- says all IR imagery still "Top Secret"
http://www.zerohedge.com/article/pr...-fukushima-thermal-imaging-continues-be-top-s

http://www.zerohedge.com/sites/default/files/images/user5/imageroot/von%20havenstein/japan_earthquaketsu_fukushima_daiichi_march18_2011_dg.jpg

http://www.digitalglobe.com/index.php/27/Sample+Imagery+Gallery

Japan's population density

http://web.stratfor.com/images/asia/map/Japan_pop_800.jpg

 

[Astronuc]

It would be interesting to see some high res satellite imagery of the FK site in the IR and XRay spectral ranges. Surely there must be some that have the capability that could be tasked to obtain them. Anyone know of any source for high res imagery of this source that might be accessible to the public? Or are they all "classified" or otherwise restricted by the DOD?

The "official news this AM seems to be "No news" -- perhaps a good thing.

I'm not sure that thermal imaging is classified, or does one refer to thermal imaging from a satellite. I imgine the security agencies do not want to reveal the true capabilities of their systems.

On the ground, thermal imaging is available. When I was a university student working in the university facilities department, I worked with an energy auditor whose specialty was thermal imaging of electrical equipment. He used a special liquid nitrogen cooled camera to image key elements of the electrical transmission and distribution system, e.g., transformer station and connections. That was in the mid 1970s.

I'm not sure about X-ray imaging at distance.

 

[antonyk]

I'm not sure that thermal imaging is classified, or does one refer to thermal imaging from a satellite. I imgine the security agencies do not want to reveal the true capabilities of their systems.

On the ground, thermal imaging is available. When I was a university student working in the university facilities department, I worked with an energy auditor whose specialty was thermal imaging of electrical equipment. He used a special liquid nitrogen cooled camera to image key elements of the electrical transmission and distribution system, e.g., transformer station and connections. That was in the mid 1970s.

I'm not sure about X-ray imaging at distance.

The utility I work for has a handful of IR cameras used exactly for what Astronuc just mentioned. They are hand portable and also can be used some distance away (from helicopters). As TEPCO is a very large utility with extensive transmission and distribution equipment, it would be safe to assume that they have these and hopefully are using them.

 

[TCups]

Possible cause of hydrogen explosion of reactors 1 and 3 is published by http://allthingsnuclear.org/post/3940804083/possible-cause-of-reactor-building-explosions" - an excellent article

What bothers me is quote "A little-known test performed decades ago at the Brunswick nuclear plant in North Carolina may hold the key to answering that question." - why little-known - this is a design limitation/fault common to many nuclear power stations. If this had been common knowledge in the nuke industry safety manuals and emergency procedures may have been rewritten - I am sure they are now being re-drafted.

Now at Fukushima containment vessel pressure has been http://www.jaif.or.jp/english/aij/110319FukushimaEventStatus-14e.pdf" *1) to be steady at .140 to .150 MPa_abs [STRIKE]which is about the same as 70PSI Gauge[/STRIKE]. Now reactor vessels 2 and 3 are reported near 0 pressure Guage that is the pressure inside the the reactor vessel is the same as the pressure in the containment vessel leading to the conclusion that the reactor vessel is breached [STRIKE]and the containment vessel 'auto-vents' as described in the article[/STRIKE].

It is also reported that sea water flooding into the reactor cores is taking place continually one of two things can happen
1- worst case it boils of and steam is vented as above then slowly a massive NaCl crust must be developing
2- best case the reactors have cooled and the containment vessel slowly filling with water

*1) Reactor 3 CV pressure 0.045MPa_abs must be a typo as it is a vacuum and I think should read as 0.145MPa_abs as in previous reports

Edit: As pointed out later pressure conversion is wrong hence wrong part struck out

AntonL:
This proposed explanation seems quite plausible but in retrospect, even more worrisome to me.

If the hydrogen gas were leaking at the drywell head, then that leak was inside the concrete containment, and so presumably was at least part of the explosion. I am wondering about the likelihood that the concrete shield plug(s) were blown off the top of the secondary (concrete wall) containment.

Although, in retrospect, a lay person would have to conclude that any hydrogen arising from a reaction involving the fuel rods would have to arise from within the reactor vessel, I had considered it got from there to the building's interior by a controlled venting process, not leakage from the drywell head, then concrete containment.

One must assume, for this mechanism to be the cause, that the concrete shield plug would not be fitted tightly enough to prevent leakage of H2. It also seems a reasonable assumption, in retrospect, that the concentration of H2 might be significantly higher under than over the concrete shield plug.

Has anyone made an assessment of the probability that the H2 explosions at Units 1, 2, and 3 blew the concrete containment plugs off like the cork on a bottle of cheap champaign?

http://media.tumblr.com/tumblr_li9czl6f4v1qbnrqd.jpg

If the diagram is accurate, it also gives a bit more insight of a hypothetical course any molten material might take from the floor of the SFP to the building's exterior.

Also, in the videos of the explosion of unit 3, I seem to remember something large and heavy falling from the vertical plume just to the side, and that someone pointed out that the blast at (unit 3?) was more vertically directed, like a cannon shooting straight upward. I have to review that video again.

Yes -- here --

Something large and heavy (who knows what), curls off to the left and comes down over the left hand tower in the video. What are the odds if it were the plug, it might be reasonably intact and visible among the debris on the ground. Back to the satellite images . . .

Hmmm. No way to tell, but it gives pause to think what might have fallen through the roof of the building in front of unit 3, doesn't it?
http://www.zerohedge.com/sites/default/files/images/user5/imageroot/von%20havenstein/japan_earthquaketsu_fukushima_daiichi_march18_2011_dg.jpg

Here's a link to the video:

http://www.youtube.com/watch?v=P6-BEOWKpAU&NR=1

I understand this is, again, all speculative, but I am compelled to try to understand what my eyes are telling me.

 

[jensjakob]

That plug looks too heavy for me to be blown off. What are the calculations?

 

[Naty1]

I wish anyone would publish SOME radiation readings ...but the one's that would be most interesting would be in the 50 mile and 15 mile evacuation areas around Fukushima...

Forgive me, but I don;t trust the reporting of anyone who does not provide some backup in terms of actual readings ...

Does anyone know how well on site control rooms are shielded?? There must be some standards...And to what extent is protection compromised when power is lost and presumably filtered ventilation fails??

 

[AntonL]

AntonL:

Has anyone made an assessment of the probability that the H2 explosions at Units 1, 2, and 3
blew the concrete containment plugs off like the cork on a bottle of cheap champaign?
.

As pictures are large, and forum entries get stretched beyond the cpu screen, I made pictures to thumbs with hyperlinkshttp://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi_march18_2011_dg.jpg"

and http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi_march14_2011_dg.jpg"

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichiov_march14_2011_dg.jpg"

and

http://www.digitalglobe.com/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi3_march16_2011_dg.jpg"

If plug popped off
Unit 1: No - roof seems to have collapsed in tact covering SFP, etc no plan features visible
Unit 2: no comment, however unit 2 is constantly emitting steam through a gap on east wall
which is said to be purposely opened. What is boiling?
Unit 3: Too much debris on roof to make any conclusions, however on March 14, shortly after explosion
steam from central part of reactor building. Note the explosion dust being carried out to sea.

 

[TCups]

That plug looks too heavy for me to be blown off. What are the calculations?

Beyond the ballistics of a 300 grain bullet, I cannot tell you. With a fuel (H2) + air explosion, volume of the reactants would have to be known. But in viewing the video and the subsequent damage, in general (as in "it looks like"), it looks like to me there was a sufficient release of energy to blow several of those plugs sky high. But then, I do not know the point where most of the energy from the blast was initially released. How big is the hole in the roof? Maybe 5-10 meters across?

Hmmm . . . no. Speaking of bullets, those are "bullet" tracks that grazed the roof of that building from side to side with one of the heavier "bullets" falling through the roof. They came from an outward blast from Unit 3 and were probably the large, reinforced concrete panels between the structural concrete beams. About the right size and number, right?

Which now gives pause to another consideration regarding Unit 4. Maybe that square hole in the side was initially a "bullet" hole.

 

[AntonL]

Which now gives pause to another consideration regarding Unit 4. Maybe that square hole in the side was initially a "bullet" hole.

No, satellite picture of March 14 posted two posts earlier just after the explosion show building of unit 4 intact