Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[sp2]

I've been following this thread since the beginning. I've seen all the analysis. The thing looks greenish but it might just be because it's in the shadow. I think it falls somewhere farther than the building anyway. The mushroom cloud is as wide as the building at this point and the object goes beyond.The remains of the FHM looks like scattered little pieces at the north end on the top view image.
There is probably enough force in the blast to launch an object that size but can that force be efficiently converted into momentum? I don't think so. The expanding gas when imparting the required acceleration to go that high would probably cause very high inertial forces that would rip it into small pieces, if the shock wave didn't already do it . It's like putting a dynamite next to it. Smaller pieces like the truss parts might survive it because they are lighter.
But maybe I'm wrong, FHM might be a very light structure welded out of bunch of metal sheets.

Emreth--

So, you carefully watched the video, which clearly shows several gigantic pieces of debris launched a thousand feet in the sky and falling back to Earth, you carefully looked at the stills, which clearly show several huge pieces of debris falling to Earth from a thousand feet in the air... and then you concluded that there couldn't possibly *be* any large pieces of debris, because they would've had to be blown into small pieces by any explosion energetic enough to launch such large pieces of debris a thousand feet in the air.

Is that about it?

I'm speechless.

 

[Emreth]

Emreth--

So, you carefully watched the video, which clearly shows several gigantic pieces of debris launched a thousand feet in the sky and falling back to Earth, you carefully looked at the stills, which clearly show several huge pieces of debris falling to Earth from a thousand feet in the air... and then you concluded that there couldn't possibly *be* any large pieces of debris, because they would've had to be blown into small pieces by any explosion energetic enough to launch such large pieces of debris a thousand feet in the air.

Is that about it?

I'm speechless.

That's not what I mean. There are large pieces thrown up a long way up but they might be the large sections of the trusses above the SFP that are missing, which I would expect to be much lighter than FHM. It's about the mass really. I find it more plausible that the FHM got blasted sideways in the first explosion towards the north wall, destroying the wall and itself.
Again like I said I might be wrong, no need to get defensive or dismissive.

 

[rasherz]

http://www3.nhk.or.jp/daily/english/06_19.html

well, it seems that many of you are well ahead of the news, again. If the situation wasn't so serious over here, I would applaud.

 

[Jorge Stolfi]

Updated my plots of #Fukushima reactor temp, pressure, water level, CAMS to NISA/METI release 76 (apr/06 08:00) :
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

 

[AntonL]

here is a site worth following showing movies of calulated dispersion in the pacific of of contamination released by Fukushima for both water born and atmospheric releases.

the dilution does not seem to be so quick as what we expect

http://sirocco.omp.obs-mip.fr/outils/Symphonie/Produits/Japan/SymphoniePreviJapan.htm

 

[AntonL]

Updated my plots of #Fukushima reactor temp, pressure, water level, CAMS to NISA/METI release 76 (apr/06 08:00) :
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

Jorge I really must thank you for your efforts in plotting this data

You may want to correct the flow rate measurements for the last couple of readings
I do not know why you omitted them, the flow rate published for Unit 1 as 6m³/h = 6000/60 = 100 l/h

 

[|Fred]

Sorry, this link added after (because i found it after) might help.http://en.wikipedia.org/wiki/Steam_explosion

Correct me If I'm not understanding this right: flash heating of water lead to fast vaporisation ie: cold watter on a hot pan. What you are suggesting is that the steam pressurized escaping the Primary containment entering the pool full of watter would flash heat the (large amount of) water in the pool ? Just like inserting a really hot metal blade into water?

Now isn't the suppression pool working exactly on the principle of cooling hot steam or gaz with water ?

as far as temperature are concerned we have a max pressure in the drywell of 0.490 MPa (75psi) does this value is consistent with a steam temperature hot enough to flash boil the pool ?

 

[NUCENG]

He he. But that is not reason not to try, is it? We are here mostly to learn, and for that asking stupid questions is essential...

I absolutely agree. I am fully qualified to ask stupid questions myself. I added that last part to explain that we need to be careful of interpreting these pictures. I have helped cleanup after floods, a house fire, tornados, and even a big earthquake in Okinawa, Japan. I can't tell you how many things you could pick up and ask "What the heck is this?" It is even more difficult when you are working only from photos, some blurred by steam, or taken through a helo window. The ability to determine scale is sometimes lost, and cameras have limited resolution. I will contribute from my experience and try to fill in BWR design information where I can.

I appreciate the imagination that has been shown and want everybody to keep looking. BTW, I just saw Charlie Sheen with his date near the Unit 4 snack bar. <};})

 

[Jorge Stolfi]

You may want to correct the flow rate measurements for the last couple of readings. I do not know why you omitted them, the flow rate published for Unit 1 as 6m³/h = 6000/60 = 100 l/h

However, from the TEPCO fax included in NISA release #76 (nominally dated apr/06 05:00), the last measurement of flow rate of unit #1 was taken on apr/03 17:30 and has not been updated since.

I do not know whether that means the rate has been stable since then. In doubt I have just been repeating the same data point at each release.

http://www.meti.go.jp/press/2011/04/20110406002/20110406002-2.pdf

 

[PietKuip]

But that does not explain the blue glows above the reactor building.

Blue glow is no evidence for criticality, only for ionization.

[PLAIN]http://m1.ikiwq.com/img/xl/zoWjYe4PwLmrJ3SmU37zUd.jpg

This is a photo of an x-ray beam at a synchrotron.

 

[Maxion]

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.[/QUOTE

But that does not explain the blue glows above the reactor building.

Wasn't the blue glow only reported by Fox Insider with no reported sources or video material? Also no other media reported on the event that cited anyone else except Fox. I think we can safely say the blue glow didn't happend.

 

[NUCENG]

For those wondering where the oxygen can come from. Water can also be split into hydrogen and oxygen by temperature alone. It occurs above 2500 C and can be catalyzed by metal oxides which lower the temperature required. When the rods in the core are not covered with water, they can reach these temperatures and produce both hydrogen and oxygen even if the zirconium cladding is already burned.

see http://en.wikipedia.org/wiki/Water_splitting

edit added better link

I am on shaky ground talking chemistry, but here is an engineering walk through:

Assume containment is intact when hydrogen begins to be released. The radiological decomposition of water into Hydrogen and Oxygen produces two moles of Hydrogen and one Mole of Oxygen per Mole of Water. If the containment is inerted with nitrogen then oxygen content is too low to support ignition, Adding the hydrogen from Zirconium waterr reaction and twice as much Hydrogen as Oxygen from radiolysis would seem to actually DECREASE the relative partial pressure of Oxygen. Wouldn't that mean there would still be too little oxygen to support a hydrogen burn or detonation.

If so there has to be pre-existing damage with inleakage of air to the containment to allow primary contaiment to be the site of the explosions. TEPCO reports indicated that pressure was above atmosoheric pressure prior to the explosions. Only unit two appeared to depressurize at the time of that explosion. This seems to indicate contaimnents were intact prior to the explosions and there should not have been a combustible or explosive atmosphere . Any Chemists out there?

 

[PietKuip]

Wasn't the blue glow only reported by Fox Insider with no reported sources or video material? Also no other media reported on the event that cited anyone else except Fox. I think we can safely say the blue glow didn't happend.

I would not exclude the possibility. The nights must be really dark in Fukushima prefecture. There are high intensities of ionizing radiation at the plant. So there should be some airglow. Maybe the dark-adapted eye can see it from a distance. Probably too faint for a video camera.

 

[NUCENG]

So the superheated water in the SFP3 littorally exploded!

In order to superheat steam in a fossile plant they take saturated steam from the boiler and rout it in tubes through the firebox. It is under pressure and unabele to expand so it superheats. How can that happen in the Spent Fuel Pool? As the water boils it is able to expand. It is not forced into close contact with a hot fuel bundle.

The alternative for superheating is pressurized water/staem inside some form of pressure vessel or pipe, If a rupture or line break occurs water being released will flash with superheat due to being under a lower pressure. How could that happen in the Spent Fuel Pool? If I remeber correctly the blowout panels on the walls of the Reactor Building are desiged for an internal pressure around 10 inches of water. There just isn't lokely to be significant superheat in the steam.

I remember discussing this with other engineers after the movie "Atomic Twister" In that film throughout the event they were watching spent fuel pool water temperature continuously increasing in temperature after it started to boil. At least they had Sharon Lawrence to smear grease on her shirt and kick the diesel so they could refill the pool.

 

[AntonL]

However, from the TEPCO fax included in NISA release #76 (nominally dated apr/06 05:00), the last measurement of flow rate of unit #1 was taken on apr/03 17:30 and has not been updated since.

I do not know whether that means the rate has been stable since then. In doubt I have just been repeating the same data point at each release.

http://www.meti.go.jp/press/2011/04/20110406002/20110406002-2.pdf

My apologies - I did not notice the note in the report.

 

[heckler73]

Won't adding Nitrogen into a Hydrogen laden environment (under pressure) make Ammonia?
N2(g) + 3 H2(g) = 2 NH3(g)

http://scifun.chem.wisc.edu/chemweek/pdf/ammonia.pdf

Less explosive, but still flammable.

 

[yuriwho]

I am on shaky ground talking chemistry, but here is an engineering walk through:

Assume containment is intact when hydrogen begins to be released. The radiological decomposition of water into Hydrogen and Oxygen produces two moles of Hydrogen and one Mole of Oxygen per Mole of Water. If the containment is inerted with nitrogen then oxygen content is too low to support ignition, Adding the hydrogen from Zirconium waterr reaction and twice as much Hydrogen as Oxygen from radiolysis would seem to actually DECREASE the relative partial pressure of Oxygen. Wouldn't that mean there would still be too little oxygen to support a hydrogen burn or detonation.

If so there has to be pre-existing damage with inleakage of air to the containment to allow primary contaiment to be the site of the explosions. TEPCO reports indicated that pressure was above atmosoheric pressure prior to the explosions. Only unit two appeared to depressurize at the time of that explosion. This seems to indicate contaimnents were intact prior to the explosions and there should not have been a combustible or explosive atmosphere . Any Chemists out there?

I am a chemist.

First, it's thermal production of H2 and O2 not radiological.
2 molecules of water produce one molecule of O2 and 2 molecules of H2
a similar reaction takes 2H2O +Zr -> ZrO2 + 2H2

The purely thermal reaction produces H2 and O2 in equal proportions. This reaction is likely what caused the explosion that blew the torus at Unit 2

 

[NUCENG]

In my travels around YouTube I found a flyover after the sea surge. Units 5&6 not shown up close but if they got saltwater in their equipment it wouldn't take long to ruined a bearing, shaft, wiring connections or a lot of other stuff. Can't find a report on how high the sea reached at the complex. Shouldn't forget about sand either.
http://www.youtube.com/watch?v=LUGAbMVG-qc"

Thanks. If we can find more sources like this it can help distinguish between damage from the tsunami and from the accident that followed.

 

[bytepirate]

I would not exclude the possibility. The nights must be really dark in Fukushima prefecture. There are high intensities of ionizing radiation at the plant. So there should be some airglow. Maybe the dark-adapted eye can see it from a distance. Probably too faint for a video camera.

you can see the cerenkov light on the webcam pics (http://www.tepco.co.jp/nu/f1-np/camera/index-j.html only at night of course). a couple of days ago it was not directly visible, but you could make it visible with photoshop. no idea, if it grew stronger, or if the webcam is adjusted.

someone monitored the spot since march 21st:
http://www.abovetopsecret.com/forum/thread672665/pg433 (3rd post on that page)

 

[AntonL]

I would not exclude the possibility. The nights must be really dark in Fukushima prefecture. There are high intensities of ionizing radiation at the plant. So there should be some airglow. Maybe the dark-adapted eye can see it from a distance. Probably too faint for a video camera.

We do know that the the open air spent fuel pools are glowing blue and the blue light is reflected in the steam rising above, although I would think that Tepco is working 24/7 and there will be lots of temporary illumination around

 

[NUCENG]

I know it's innappropriate but why do I keep hearing the William Tell Overture ? "BOOM!"

The Lone Ranger Theme? or did you mean the 1812 Overture?

 

[|Fred]

animated picture with some annotations
[PLAIN]http://i.min.us/ikyAQe.gif

 

[razzz]

animated picture with some annotations
[PLAIN]http://i.min.us/ikyAQe.gif[/QUOTE]

Why the reddish color of the debris cloud? It only last a few seconds then fads in real time.

 

[razzz]

http://www.youtube.com/watch?v=-W7uGvW8xvY&feature=player_embedded"

 

[Borek]

Assume containment is intact when hydrogen begins to be released. The radiological decomposition of water into Hydrogen and Oxygen produces two moles of Hydrogen and one Mole of Oxygen per Mole of Water. If the containment is inerted with nitrogen then oxygen content is too low to support ignition, Adding the hydrogen from Zirconium waterr reaction and twice as much Hydrogen as Oxygen from radiolysis would seem to actually DECREASE the relative partial pressure of Oxygen. Wouldn't that mean there would still be too little oxygen to support a hydrogen burn or detonation.

Chemical parts of your analysis look OK to me. I guess there is even more to it when it comes to low level of oxygen. Hydrogen/oxygen mixture is not thermodynamically stable, and if you don't separate hydrogen and oxygen fast, they will tend to react back to create water, especially in high temperatures (hydrogen/oxygen mixtures at STP are only kinetically stable). IMHO you can have some small amount of hydrogen & oxygen from water splitting present and much more hydrogen from Zr and water reaction. According to LeChateliers principle amount of free oxygen in the presence of excess hydrogen should be even lower than it could be if there was no hydrogen from Zr/water reaction.

 

[artax]

I hope it's a matter of translation problems and/or exhaustion of the tech workers, and not a matter of incompetence. Finding high levels of very short-lived isotopes (indicative of on-going fission) should have set off some mental alarms in the engineering/technical staff, prompting a lot of double-checking.

With talk of entombment in some circles, this raises a concern in my mind. The process of setting/curing concrete is exothermic. Could entombment result in insufficient cooling of fuels, leading to unanticipated problems? Coming at this from a civil/mechanical mind-set with NO experience in nuclear leaves a lot of questions.

Yes, I think anyone suggesting setting in concrete does not understand the fundamental behaviour of nuclear fuel and the issue of cooling .
Entombment, without some form of gas escape route before colling for years is just silly!

 

[Borek]

Won't adding Nitrogen into a Hydrogen laden environment (under pressure) make Ammonia?
N2(g) + 3 H2(g) = 2 NH3(g)

To get good efficiency you need something like 20 MPa, 400 deg C and a catalyst. Some traces were for sure produced, but not much.

 

[artax]

I know it's innappropriate but why do I keep hearing the William Tell Overture ? "BOOM!"

did you ever play an early computer game called 'BATTLEZONE'?

http://www.youtube.com/watch?v=ghIPGXs3LAo&feature=player_detailpage#t=125s

 

[ian_scotland]

As to panel trajectories from Unit 3...

Sketches I made some time ago but didn't post are attached. These were intended as a reply to a much earlier question about the origin of an almost intact panel leaning against the building just East of the turbine building.

The specific panel in question probably was a Southmost-East facing panel from either the top or second row of panels of Unit 3.

BTW - perspective does make it difficult to judge the source...

.

I see why you would think that this is a wall panel from no.3 reactor building, but that is not a rf conc wall panel you have found - its the flat roof over the entrance to that small building.

I am trying to find a pre-BOOM photo of the site to illustrate this.
Found (not my image annotation, but shows the small flat roof in question)
https://lh5.googleusercontent.com/-...kk/s1600/FukushimaDaiichi-overhead+-+Copy.PNG

 

[NUCENG]

I am a chemist.

First, it's thermal production of H2 and O2 not radiological.
2 molecules of water produce one molecule of O2 and 2 molecules of H2
a similar reaction takes 2H2O +Zr -> ZrO2 + 2H2

The purely thermal reaction produces H2 and O2 in equal proportions. This reaction is likely what caused the explosion that blew the torus at Unit 2

OK I agree with the equation for Zr-H20 reaction, but that yields only ZrO2 which is a solid and H2 gas.

Radiologial or Thermal whatever the source, isn't the equation:
2H2O -> 2H2 + O2

I remember PV = NRT where N is in moles. If you are releasing two molecules of Hydrogen gas for each molecule of oxygen, then the partial pressure of hydrogen increases at twice the rate of Oxygen in a constant volume with both gasses at the same temperature.

The N2 gas and steam would have a constant partial pressure at a given temperature. So as the total pressure rises due to steam Nitrogen, Hydrogen and Oxygen, the partial pressure of Hydrogen would increase from zero before the fuel damage to some new value. and the partial pressure of oxygen would increase from a low inerted pressure to its new value, but at half the rate of the hydrogen. Volumetrically the same relationship is present. Does the containment ever reach an explosive or ignition concentration if the % of oxygen is insufficient for ignition and continues to decrease? What am I missing?

If it does reach an explosive point without air inleakage, it begs the question of why NRC requires BWR MK1 containments to be inerted. Are we sure the Japanese inert their plants? There are tanks on the Fukushima site that look like our liqiud nitrogen storage tanks at US BWRs.