FUKUSHIMA earthquake and tsunami thread and aftermath

[Hyperduck Quack Quack]

Yeah, but the point you were making was about getting water into something that was sealed. If it's sealed there's no water getting in/out, if it isn't then there's no pressure problem.

Which is it?

I think they mean sealed apart from inlets / outlets and valves that allow water in and out, as part of the normal circulation between a reactor, turbines, condensing plant etc., through which water could theoretically be added - except we don't know 1) if anyone can get near enough to any of the gubbins to do anything to it now, and 2) whether any of the relevant valves still work. Edited March 14, 2011 by Hyperduck Quack Quack

[Bloo Loo]

It explodes. It's a peculiarly dangerous explosion, because the superheated water flashes into steam as the pressure reduces driving even more expansion than the initial gas expansion. Think shaken champagne when you release the pressure. It's what safety valves try to avoid.

Of course, Im just thinking through the chain of events as seen from the pile....

It looks to me that venting is a foregone conclusion as left on its own, the thing is bound to rupture uncontrollably...they have already vented and we have had two explosions by combustable gas.

Lets hope the sea water can cool me down quickly....but if part of me is in steam...the job just got a magnitude harder.

EDIT now lokking at this diagram, things become clearer.

I am covered in water that is used to turn the turbines once boiled.

This water is gone and they have managed to pump seawater in place....

Edited March 14, 2011 by Bloo Loo

[bogbrush]

I am covered in water that is used to turn the turbines once boiled.

This water is gone and they have managed to pump seawater in place....

In which case there shouldn't be an explosive pressure build. At least that's how it looks to my eyes.

[Alan B'Stard MP]

I dunno...I hear...they are passing seawater in to cool the thing off....it has to contact the heatsource to cool it.

Not so sure. Memories of O level physics tell me convection would do the trick? Radiation in a vacuum?

Edited March 14, 2011 by Alan B'Stard MP

[pete.hpc]

Do you mean a fully fuelled 747 at 300mph crashing into a centre of population? We saw what happened when that happens in Lockerbie. The chances of one coming down over a very densely populated area are very low, because they tend not to fly directly over them, except for a tiny proportion of their overall flight time (in order not to get in the way of other planes arriving at and departing from the city's major airport). But if one slammed into a housing estate or other densely populated patch of land, it would cause considerable loss of life, injury and economic damage in the short term and localised. But it would not cause the long-term an and wide area problems that radiation leakage does.

No, I meant for all the protection against natural disasters, how would they stand up to a hijacked aircraft being flown into the reactor building.

[Bloo Loo]

In which case there shouldn't be an explosive pressure build. At least that's how it looks to my eyes.

but, the turbines are gone and steam vented off? this leaves the undamaged secondary container...remember, the pumps needed to put water into the pressure systme failed. so water wasnt put in following the vent....hence seawater...which, it is rumoured dont cover the pile.

[Errol]

Gamma Radiation In Fukushima Downwind Ibaraki Disclosed, 30 Times Above Normal

And the data is stunning: based on a N, NE and NNE wind direction (where it originates), meaning all coming from Fukushima, with a normal reading in the 80 nGy/h range, the city of Kounosu Naka is at 3,024, Kadobe Naka is at 2,416, Isobe Hitachioota is at 1,213 and many others are in the mid to upper triple digit range! Again, this is based on wind coming out of Fukushima and ultimately headed toward the capital. Indicatively, normal terrestrial plus cosmic gamma radiation is about 80 nGy/h.

http://www.zerohedge.com/article/gamma-radiation-fukushima-downwind-ibaraki-disclosed-30-times-above-normal

[corevalue]

Not so sure. Memories of O level physics tell me convection would do the trick? Radiation in a vacuum?

Not even remotely close. Think of trying to boil water with an old-fashioned 3 bar electric fire. You need good intimate contact to pass heat at these energy levels. as my missus says.

[bogbrush]

but, the turbines are gone and steam vented off? this leaves the undamaged secondary container...remember, the pumps needed to put water into the pressure systme failed. so water wasnt put in following the vent....hence seawater...which, it is rumoured dont cover the pile.

I get you, but bottom line I doubt these things are designed so a failure of pump renders it explosive. That's not based on technical knowledge, but it wouldn't seem a smart idea by the clever bods who design these things.

I reckon all will be ok, it's scary stuff for those involved but one heck of a lot of thought gets put into this stuff and it's not Soviet Russia. It might be my imagination but I get a sense from whatever sources there are that this might have gone past the greatest risk of them being unable to get water cooling going.

[Alan B'Stard MP]

Not even remotely close. Think of trying to boil water with an old-fashioned 3 bar electric fire. You need good intimate contact to pass heat at these energy levels. as my missus says.

Sorry but my BS alarm is ringing loudly.

Have you a got a link or worked example?

Edited March 14, 2011 by Alan B'Stard MP

[Errol]

8.59pm: The New York Times has some rather worrying quotes from concerned nuclear industry executives in the US who have been talking to Japanese counterparts amid faltering emergency operations to pump seawater into one of the crippled reactors at the Fukushima Daiichi Nuclear Power Station:

"They're basically in a full-scale panic" among Japanese power industry managers, said a senior nuclear industry executive.

The executive is not involved in managing the response to the reactors' difficulties but has many contacts in Japan. "They're in total disarray, they don't know what to do."

http://www.guardian.co.uk/world/blog/2011/mar/14/japan-tsunami-nuclear-alert-live

[bogbrush]

Gamma Radiation In Fukushima Downwind Ibaraki Disclosed, 30 Times Above Normal

And the data is stunning: based on a N, NE and NNE wind direction (where it originates), meaning all coming from Fukushima, with a normal reading in the 80 nGy/h range, the city of Kounosu Naka is at 3,024, Kadobe Naka is at 2,416, Isobe Hitachioota is at 1,213 and many others are in the mid to upper triple digit range! Again, this is based on wind coming out of Fukushima and ultimately headed toward the capital. Indicatively, normal terrestrial plus cosmic gamma radiation is about 80 nGy/h.

http://www.zerohedge.com/article/gamma-radiation-fukushima-downwind-ibaraki-disclosed-30-times-above-normal

This guy seems to think otherwise;

If you live in a poorly vented house on a fairly radioactive part of Dartmoor you get a dose of about 50mSv a year (source: http://hansard.millbanksystems.com/written_answers/1987/feb/05/radiation). Divide that by 365*24 to get your average hourly dose and you get 5707 nSv per hour. A nSv is roughly equivalent to a nGy (actually it's a bit more but about the same order of magnitude - see http://en.wikipedia.org/wiki/Sievert) so you'd be getting about the same levels of radiation sitting in your living room in Princetown.

Don't ask me!

[Bloo Loo]

Not so sure. Memories of O level physics tell me convection would do the trick? Radiation in a vacuum?

true, but air is not as good a heatsink as a fluid....otherwise they could simply blow air around the system, bit like an airconditioner...Clearly, this is not efficient enough to work.

Edited March 14, 2011 by Bloo Loo

[bogbrush]

8.59pm: The New York Times has some rather worrying quotes from concerned nuclear industry executives in the US who have been talking to Japanese counterparts amid faltering emergency operations to pump seawater into one of the crippled reactors at the Fukushima Daiichi Nuclear Power Station:

"They're basically in a full-scale panic" among Japanese power industry managers, said a senior nuclear industry executive.

The executive is not involved in managing the response to the reactors' difficulties but has many contacts in Japan. "They're in total disarray, they don't know what to do."

http://www.guardian.co.uk/world/blog/2011/mar/14/japan-tsunami-nuclear-alert-live

You lost me at "Grauniad".

[Alan B'Stard MP]

true, but air is not as good a heatsink as a fluid....otherwise they could simply blow air around the system, bit like an airconditioner...Clearly, this is not efficient enough to work.

I understand air doesn't have the specific heat capacity of water - but would it act as a bottleneck to heat transfer?

Edited March 14, 2011 by Alan B'Stard MP

[Hyperduck Quack Quack]

They say that if the reactor goes out of control and into meltdown, with the fuel rods not surrounded by water, the temperature could reach 4000 degrees. If that happens, surely there would be enough conducted or radiated heat to weaken or melt the steel walls of the pressure vessel (steel melts at about 1400 degrees, depending on its type.)

If you have a reactor at approaching 4000 degrees and you then pump water into it, the heat shock could cause the bonds of the H2O molecules to break, so the water to separate into hydrogen and oxygen, which will re-combine again with a violent explosion as the shock subsides.

Edited March 14, 2011 by Hyperduck Quack Quack

[Damik]

OK, I am a melting reactor, and I live in a sealed steel pressure vessel.

I am surrounded with sea water and I am still heating up, as part of me is uncovered.

In the gap above the water is steam from the water I am boiling.

It has nowhere to go.

pressure is building.

and they need to get more water to me.

what next? what happens to a steam engine on overheat?

there are a few passive safety release vents to release the dangerous amount of the pressure to avoid the explosion ...

[Alan B'Stard MP]

there are a few passive safety release vents to release the dangerous amount of the pressure to avoid the explosion ...

Didnt the tepco representative say that some of these were sticking?

[Bloo Loo]

I get you, but bottom line I doubt these things are designed so a failure of pump renders it explosive. That's not based on technical knowledge, but it wouldn't seem a smart idea by the clever bods who design these things.

I reckon all will be ok, it's scary stuff for those involved but one heck of a lot of thought gets put into this stuff and it's not Soviet Russia. It might be my imagination but I get a sense from whatever sources there are that this might have gone past the greatest risk of them being unable to get water cooling going.

the explosive bit is the hydrogen/oxygen mix caused by the massive heat, I gather.

meanwhile, in my pressure vessel, the pressure is rising.....

As the scientists have said, the half life of the elements causing the heat is about 10 days or so...so really, a bit like QE, they hope to keep things on the good side of safe as best they can.

What worries me is the change of wording from Earthquake PROOF to Earthquake RESISTANT....

would people have agreed to have these things if the latter description was made known...

[Bloo Loo]

there are a few passive safety release vents to release the dangerous amount of the pressure to avoid the explosion ...

vents to where?

and how often are they to vent?

is this as good as open to the air?

[mentholist]

I get you, but bottom line I doubt these things are designed so a failure of pump renders it explosive. That's not based on technical knowledge, but it wouldn't seem a smart idea by the clever bods who design these things.

I reckon all will be ok, it's scary stuff for those involved but one heck of a lot of thought gets put into this stuff and it's not Soviet Russia. It might be my imagination but I get a sense from whatever sources there are that this might have gone past the greatest risk of them being unable to get water cooling going.

Whilst I tend to agree with you anti catastrophist agenda you cannot ascribe onimpotence to "clever bods". it seems obvious to me that as soon as we got to "It's O.K we'll just vent the hydrogen like it's designed to" "BOOOOOOM!" "WTF was that?", "Er we appear to have blown more than the bloody doors off" we'd passed the point at which design was managing some of the problems.

Ultimately it may be however that the rest of the design is sound enough to handle whatever is happening. Though if the BBC are right (yes I know) and they are flooding the primary with sea water and they still can't keep it cool does that preclude further venting? If so, I can see a situation where they are making things worse.

[Errol]

They barely know what they are doing. That's the point. All anyone can do is wait now. We should know within a day or so.

[bogbrush]

the explosive bit is the hydrogen/oxygen mix caused by the massive heat, I gather.

meanwhile, in my pressure vessel, the pressure is rising.....

As the scientists have said, the half life of the elements causing the heat is about 10 days or so...so really, a bit like QE, they hope to keep things on the good side of safe as best they can.

What worries me is the change of wording from Earthquake PROOF to Earthquake RESISTANT....

would people have agreed to have these things if the latter description was made known...

It's a bit of sophistry really; I mean, if a big hole opened up beneath them and the whole thing fell 400 feet down would it be supposed to stand up to it?

It'll be interesting what happens after this has played out. It's getting a vast share of the coverage because.... well like I say we get brought up in terror of mushroom clouds but no matter how this goes it can't come close to the risk of building towns on the coast. I bet there'll be many, many tens of thousands dead after all this just because of ordinary water.

[Alan B'Stard MP]

They barely know what they are doing. That's the point. All anyone can do is wait now. We should know within a day or so.

Have you got a lead box for your sovereigns?

[corevalue]

Sorry but my BS alarm is ringing loudly.

Have you a got a link or worked example?

Do you know why you need heatsink compound between the CPU and it's heatsink? It's because just an invisibly thin layer of air is sufficient an insulator to make the CPU overheat. In convection cooling, a given mass of air has about the same thermal carrying capacity as the same mass of water. 1kg of air is about 1 cubic meter, water is 1000 times as dense, so air is about 0.1% as effective as water in convection cooling, volume for volume

The best cooling is evaporation of water, which this reactor is designed to do in it's normal operation.