Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[rhody]

I don't think he was in any great danger (especially from radiation) other than that is normally associated with flying an apparatus that drops like a boiled egg when the rotors stop. You didn't see him flying directly over the units or through a steam cloud did you?

Reno,

No, pilot safety was only part of my concern, of course he made the flyby as quick as possible and not directly in a vapor stream. From the looks of it, he used a hand held (not HD camera to take that video). The http://en.wikipedia.org/wiki/General_Atomics_MQ-1_Predator" is capable of staying aloft for 40 hours and has a cruise speed of over 70kt.

The surveillance and reconnaissance payload capacity is 450lb and the vehicle carries electro-optical and infrared cameras and a synthetic aperture radar. The two-color DLTV television is equipped with a variable zoom and 955mm Spotter. The high resolution FLIR has six fields of view, 19mm to 560mm.

This platform can provide superior visual and thermal imagery that would be invaluable to teams on the ground assessing the situation. I would not be surprised to learn sometime in the distant future that one or more of our Keyhole spy satellite's had been directed to use it's precious maneuvering gases to overfly, sense and record the crippled reactor's in Japan. Only time will tell what if any information was gathered, analyzed and then provided to our president in his daily security brief.

Rhody...

 

[Angry Citizen]

The predator is capable of staying aloft for 40 hours and has a cruise speed of over 70kt.

You'd think the military would have hardened it against ionizing radiation to combat the effectiveness of tactical nuclear weapons, but the Predator may not have been built with that in mind. After all, the engineers who designed Fukushima's EDG system didn't consider the possibility of a tsunami. Boneheads.

 

[rhody]

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. In fact, IIRC, they went prompt critical, which is a BIG NO-NO!

The other effect in play with respect to cooling water in the RBMK, when the water gets hot, particularly when it boils (becomes vapor), it also absorbs less neutrons, and so that has positive reactivity coefficient. Generally, LWRs are designed for negative reactivity coefficients for moderator density and fuel temperature (Doppler) effects.

Why is the range from 3 to 10 million electron volts so damaging to human cells? The higher the energy the more penetrating the gamma. 3-10 MeV just happen to have the right energy range to be penetrating, but not so penetrating that they pass through. In other words, they will penetrate and produce secondary radiation via the photoelectric and Compton effects, and even pair prodcution.

I'll leave that for a biophysicist.


BTW - http://news.nationalgeographic.com/news/energy/2011/03/1103165-japan-nuclear-chernobyl-three-mile-island/

Thanks Astronuc,

You are providing insight that would not possible to obtain otherwise, and since you are a mentor on here, we reap the benefit, a win, win.

Rhody...

 

[rhody]

You'd think the military would have hardened it against ionizing radiation to combat the effectiveness of tactical nuclear weapons, but the Predator may not have been built with that in mind. After all, the engineers who designed Fukushima's EDG system didn't consider the possibility of a tsunami. Boneheads.

Angry,

How can you be so sure it wasn't ?

Rhody...

 

[Reno Deano]

Live stream on http://www3.nhk.or.jp/nhkworld/" just reported there's TEPCO Fukushima Daiichi workers who have now received maximum radiation dose of 100mSv and that they would not be sent back in.

TEPCO's actions are in keeping with responsible health physics practices for emergency workers and the current situations.

Dean Chaney, CHP

 

[Reno Deano]

Has anyone seen any offsite radionuclide specific measurement data? Hand held gamma specs are dime a dozen in Japan! Every measurement team should have one. They also should have analyzed insitu air samples, by now.

 

[Astronuc]

Has anyone seen any offsite radionuclide specific measurement data? Hand held gamma specs are dime a dozen in Japan! Every measurement team should have one. They also should have analyzed insitu air samples, by now.

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

 

[Angry Citizen]

Angry,

How can you be so sure it wasn't ?

Rhody...

I'm as uncertain as you are. I simply wanted to offer a possible explanation. We know a few facts. 1) Predators are dependent on a dense network of sophisticated electronics. 2) Any significant electronic interference would disrupt unshielded electronics. 3) Predators are designed to be lightweight, meaning it's possible that some engineer decided to nix shielding on account of weight or cost or some combination of the two. 4) Predators aren't necessarily designed for a nuclear-armed opponent. AFAIK, they were developed to combat guerrillas and insurgents whose technological capabilities are low, or to observe enemy positions before engagement. Radiation shielding would fall far outside necessity for such missions, since guerrillas don't tend to carry Fukushima nuclear plants on their backs, and modern warfare doesn't tend to include the risk of tactical nuclear weapons.

But I would take this analysis with a grain of salt. For all I know, the American military decided to be greedy and didn't want to risk a multi-million dollar plane. Or it's like someone else said: maybe we've got a satellite up there with sufficient imaging capabilities, but it's not being released to the public in order to keep our spy satellites' capabilities unknown (this possibility also applying to the lack of Predators).

 

[rhody]

Angry,

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

Rhody...

 

[PoC83]

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?

 

[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

 

[rhody]

In the https://www.physicsforums.com/showpost.php?p=3197547&postcount=539" above, first picture, from left to right, (edited 1:06pm) first long rectangular building, see the whole described by TCups in the previous post ? TCups said he thought he saw something large and heavy fall from the video which had the big vertical plume. In his post he said to the left of the tower, I am wondering out loud if that could be remnants of the "plug" he spoke of ? Because the image is rotated 180% and is now right oriented it fits perfectly with what he claims to have seen. Could the plug or remnants of it be inside the building ? Had we not been given access to the high res photo, this would not be possible, way to go, AntonL. You guys are doing with access to free information what is needed, trying to piece the puzzle together, and I must say doing a fairly amazing job at it. Keep up the good work.


Rhody...

 

[TCups]

Everything I see says the greatest force of the blast at 3 was sideways. Another "bullet" hit in a building in back of unit 3. But most of the girder structure of the roof seems intact. I can't see any good candidates for the "plug". Sure wish we had thermal imaging to study.

 

[Maxion]

Everything I see says the greatest force of the blast at 3 was sideways. Another "bullet" hit in a building in back of unit 3. But most of the girder structure of the roof seems intact. I can't see any good candidates for the "plug". Sure wish we had thermal imaging to study.

That is true, there are quite a lot of IFs in the situation. We don't even know how the reactor in the GE test differs or doesn't from Fukushima 1-3. But the round hole in the turbine building infront of 1-3 is quite interesting in my opinion. I would say the evidence is in favor of the containment buildings cap blowing off, but there are very many if's to be able to say so conclusively.

What do you think, Astronuc? I'd say you would be the best person to guestimate based on the info we have.

 

[Astronuc]

Regarding the plug covering the reactor cavity, I believe the expectation is the hydrogen explosions occurred in the upper or secondary containment, i.e., in the volume of the metal building structure atop the concrete containment. The explosion would then be above the plug.

As far as I know, the emergency plan would be to flood containment with water, which would prevent accumulation of hydrogen, but perhaps there is some voiding (?). Hydrogen rises, so it goes up by the most available pathway. There is a venting system from containment to the tall stacks (towers) that one sees adjacent to each reactor building. It appears that Units 1 & 2 share a stack. Ideally, the atmosphere from containment is filtered and where possible, delayed to allow decay of short half-lived fission gases.

An explosion in containment would be a concern. A strong blast over the spent fuel pool, especially with a reduced pool level would also be of concern with respect to the integrity of the wall, particularly the wall toward the outside of the building.

 

[rhody]

FYI

Not to interrupt the train of thought but here is http://www.iaea.org/newscenter/news/tsunamiupdate01.html" as of March 19, 2011.
I haven't read it fully and digested it yet, it may or may not shed some light on this discussion.
I have included a screen grab of a damage assessment table in the link. Another piece of the puzzle, have at it guys...

Rhody...

edit: P.S. AntonL made a similar post in https://www.physicsforums.com/showpost.php?p=3196974&postcount=521" above, it is the same data, with a greater level of detail than the official IAEA chart in thumbnail above, compare if you wish...

 

[warren_c]

Video of a fire truck spraying water on no. 3:

 

[AntonL]

But the round hole in the turbine building infront of 1-3 is quite interesting in my opinion.

I do not think it is a round hole, video taken on a cloudy day and we would not see into the generator hall as it would be too dark. I think that black is some steel cladding with a roof beam lying on top, similar roof beams from unit 3 can be seen scattered.

 

[TCups]

I do not think it is a round hole, video taken on a cloudy day and we would not see into the generator hall as it would be too dark. I think that black is some steel cladding with a roof beam lying on top, similar roof beams from unit 3 can be seen scattered.

Look again. Clearly, 4 large pieces of debris blasted outward from the wall of Unit 3. Two of 4 chunks traversed the roof of the turbine bldg, damaging the far wall of the turbine bldg. Two more hit the near wall of the turbine bldg, then made it part of the way, then fell through the roof. These were likely the concrete panels between the structural columns of Unit 3.

http://i306.photobucket.com/albums/nn270/tcups/Picture1-3.png

 

[AntonL]

Look again. Clearly, 4 large pieces of debris blasted outward from the wall of Unit 3. Two of 4 chunks traversed the roof of the turbine bldg, damaging the far wall of the turbine bldg. Two more hit the near wall of the turbine bldg, then made it part of the way, then fell through the roof. These were likely the concrete panels between the structural columns of Unit 3.

Yes I can see the 'shaving' marks left by horizontal moving bodies, but these do not cause holes, for holes we need a vertical impact. Also note the black area is the end of the skid mark, so we looking at the body that marked the roof, other two skid marks damaged the east side fascia and whatever caused the marking then fell to the ground.

I still firmly believe the roof of the generator hall has not been penetrated and is intact other than the skid marks and fascia damage.

 

[romillyh]

Video of a fire truck spraying water on no. 3:

And, in case it's any help, story of same with diagram of unmanned truck and seawater pump unit in The Japan Times:

http://search.japantimes.co.jp/cgi-bin/nn20110320a1.html

Aimed at cooling spent MOX in no. 3 pool. We live in hope. (Apols if someone has already posted link -- I checked but can't see it)