Japan Earthquake: nuclear plants

*AntonL*

Quote by Jorge Stolfi

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/...10406002-2.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

Quote by NUCENG

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

Quote by razzz

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.
Aerial video shows immediate aftermath of 14m tsunami at Fukushima

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

Quote by PietKuip

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*

Quote by PietKuip

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

Quote by ninefingers

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

razzz

Quote by |Fred

animated picture with some annotations

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

razzz · Fukushima Daiichi Reactors 5-6 Stability Under Threat 04.04.11

Fukushima Daiichi Reactors 5-6 Stability Under Threat 04.04.11

Borek

Quote by NUCENG

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

Quote by turbo-1

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

Quote by heckler73

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

Quote by ninefingers

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=ghIPG...ailpage#t=125s

ian_scotland

Quote by tyroman

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/-r...ead+-+Copy.PNG

NUCENG

Quote by yuriwho

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.

Borek

Quote by yuriwho

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

Judging from the diagram posted earlier

http://www.physicsforums.com/attachm...9&d=1302058688

you need around 12% oxygen by volume for the explosion. Seems unlikely in the conditions present inside. Thermal decomposition of water needs fast separation of products, otherwise they react back.

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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.

razzz	Fukushima Daiichi Reactors 5-6 Stability Under Threat 04.04.11