News this morning NZ time is that the levels are falling and it is cooling.
Seen about the cooling water can be on fire on TV before.

Quote0146 : Tepco says the reactor 3 at Fukushima Daiichi nuclear power plant has been emitting white smoke for about 45 minutes, Kyodo News reports. The plant's reactor 4 was the one where a fire broke out earlier this morning

Quote0221: Japanese Cabinet Secretary Yukio Edano says the authorities are still looking for the cause of white smoke billowing from reactor 3 at Fukushima Daiichi nuclear power plant. He says the radiation reading at the plant is fluctuating by the hour.

Quote0236: Mr Edano, Japan's chief government spokesman, says workers trying to douse the reactors with water were forced to retreat when radiation levels surged there.

Quote0320: Staff have now been evacuated from Fukushima because of a spike in radiation levels, Chief Cabinet Secretary Yukio Edano told a news conference.

It still doesn't look good.

More bad news as Snow has been confirmed in some areas, while people left homeless will face some harsh freezing weather conditions.

There was a young man from Japan,who, once fell asleep in his van.He woke in the night, with a terrible fright.And found he was now in Taiwan.

its all f**ked out there now. kaboom

the increasingly improvised methods of water injection concern me. I also find it most concerning that TEPCO brought up the possibility of unintentional criticality in the cooling ponds at R4. If they've brought it up, they think it could actually happen and a self sustaining fission reaction outside the containment vessel would be really bad. Probably still not Chernobyl bad, but at that point it would be demonstrably significantly worse than three mile island.

They need to get boric acid or some other neutron absorber into that cooling pond water, but presumably if they could do that easily they'd just have done it rather than mentioning that criticality was ever on the cards.

very worrying.

Quote from: Mongoose on March 16, 2011, 15:49:12 PM
the increasingly improvised methods of water injection concern me. I also find it most concerning that TEPCO brought up the possibility of unintentional criticality in the cooling ponds at R4. If they've brought it up, they think it could actually happen and a self sustaining fission reaction outside the containment vessel would be really bad. Probably still not Chernobyl bad, but at that point it would be demonstrably significantly worse than three mile island.

They need to get boric acid or some other neutron absorber into that cooling pond water, but presumably if they could do that easily they'd just have done it rather than mentioning that criticality was ever on the cards.

very worrying.

what they tell us today, probably happened 2 days ago.

Quote from: Eggtastico on March 16, 2011, 16:16:58 PM

Quote from: Mongoose on March 16, 2011, 15:49:12 PM
the increasingly improvised methods of water injection concern me. I also find it most concerning that TEPCO brought up the possibility of unintentional criticality in the cooling ponds at R4. If they've brought it up, they think it could actually happen and a self sustaining fission reaction outside the containment vessel would be really bad. Probably still not Chernobyl bad, but at that point it would be demonstrably significantly worse than three mile island.

They need to get boric acid or some other neutron absorber into that cooling pond water, but presumably if they could do that easily they'd just have done it rather than mentioning that criticality was ever on the cards.

very worrying.

what they tell us today, probably happened 2 days ago.

Have to agree, seems to be a whiff of deliberately holding back the facts

Quote from: matt5cott on March 16, 2011, 16:26:16 PM

Quote from: Eggtastico on March 16, 2011, 16:16:58 PM

Quote from: Mongoose on March 16, 2011, 15:49:12 PM
the increasingly improvised methods of water injection concern me. I also find it most concerning that TEPCO brought up the possibility of unintentional criticality in the cooling ponds at R4. If they've brought it up, they think it could actually happen and a self sustaining fission reaction outside the containment vessel would be really bad. Probably still not Chernobyl bad, but at that point it would be demonstrably significantly worse than three mile island.

They need to get boric acid or some other neutron absorber into that cooling pond water, but presumably if they could do that easily they'd just have done it rather than mentioning that criticality was ever on the cards.

very worrying.

what they tell us today, probably happened 2 days ago.

Have to agree, seems to be a whiff of deliberately holding back the facts

I concur, which is why I find it particularly alarming that THEY brought up the criticality thing. If they have said, without prompting, that it's a possibility....... TBH the only reason I'm not saying it's already happened is that I'm reasonably sure we'd know about it if it had, the cooling ponds aren't designed to dissipate that kind of heat so my guesstimate is that a criticality event would boil the pond dry in a few minutes at most, at which point it would very quickly become a very large fire. The fission reaction would lose moderation and therefore probably stop as soon as the water boiled off, but molten fuel rods would then be a certainty and compromised fuel outside the reactor + fire...

like I said, they really need to get neutron absorbers in there, but apparently radiation has forced back the helicopters back so they're now going to try and use water-canon.

Up to this point I've been pretty relaxed about the whole situation. I am now genuinely concerned. 

Quote from: Mongoose on March 16, 2011, 15:49:12 PM
the increasingly improvised methods of water injection concern me. I also find it most concerning that TEPCO brought up the possibility of unintentional criticality in the cooling ponds at R4. If they've brought it up, they think it could actually happen and a self sustaining fission reaction outside the containment vessel would be really bad. Probably still not Chernobyl bad, but at that point it would be demonstrably significantly worse than three mile island.

They need to get boric acid or some other neutron absorber into that cooling pond water, but presumably if they could do that easily they'd just have done it rather than mentioning that criticality was ever on the cards.

very worrying.

One of them will soon go,
"I know, Rets Pee on it"

https://www.facebook.com/notes/international-atomic-energy-agency-iaea/japanese-earthquake-update-16-march-2200-utc/202327553130372

Temperature of Spent Fuel Pools at Fukushima Daiichi Nuclear Power Plant



Spent fuel that has been removed from a nuclear reactor generates intense heat and is typically stored in a water-filled spent fuel pool to cool it and provide protection from its radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies.  According to IAEA experts, a typical spent fuel pool temperature is kept below 25 ˚C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.



Given the intense heat and radiation that spent fuel assemblies can generate, spent fuel pools must be constantly checked for water level and temperature. If fuel is no longer covered by water or temperatures reach a boiling point, fuel can become exposed and create a risk of radioactive release. The concern about the spent fuel pools at Fukushima Daiichi is that sources of power to cool the pools may have been compromised.



The IAEA can confirm the following information regarding the temperatures of the spent nuclear fuel pools at Units 4, 5 and 6 at Fukushima Daiichi nuclear power plant:



Unit 4

14 March, 10:08 UTC:  84 ˚C

15 March, 10:00 UTC:  84 ˚C

16 March, 05:00 UTC:  no data



Unit 5

14 March, 10:08 UTC:  59.7 ˚C

15 March, 10:00 UTC:  60.4 ˚C

16 March, 05:00 UTC:  62.7 ˚C



Unit 6

14 March, 10:08 UTC:  58.0 ˚C

15 March, 10:00 UTC:  58.5 ˚C

16 March, 05:00 UTC:  60.0 ˚C



The IAEA is continuing to seek further information about the water levels, temperature and condition of all spent fuel pool facilities at the Fukushima Daiichi nuclear power plant.

Click for a bigger version...

I have no idea.... but I assume the pools are deep enough so that as they start to overheat, water will evaporate cooling them off ?

I know the spent fuel pool at Hartlepool nuclear power station is pretty much jammed full of radioactive crap as a result of the miners strikes in the 80's
(all the nuke power stations had to run at more than 100% to make up for the loss of coal power stations, which apparently depletes the fuel ultra fast)

I'd assume.... worse case scenario is, they'll get firemen to pump sea water into the pools ?


as for the earlier bit about venting steam / the explosions etc...

the original steam apparently isn't radioactive at all - because it;s from pure distilled water

but the steam from the sea water is very slightly radioactive (half life of seconds apparently) because of the salt/crap in the water interacting with the fuel rods....
(they also mixed in some..... can;t remember what it's called but it's what the control rods are made out of.... the reactor is no good once the sea water hits it anyway, so they might as well finish it off)

when they vented the (radioactive) sea water steam, instead of venting it straight to the atmosphere they vented it into the containment building, held it there for a short while and then vented it to the atmosphere.... (it's only radioactive for a very short time, so by holding it, it's just normal steam by the time they release it)

they apparently knew that there was a chance it could split into hydrogen and oxygen inside the containment building (it can't split inside the reactor, can't remember why) but they decided to risk it.... it (apparently) doesn't make any difference that the containment buildings "exploded" the stuff inside is build to take it....   (the building's themselves didn't really explode... there were explosions inside knocking the roof etc.. off but not a lot more)

I thought these nuclear power stations were supposed to be 110% safe? They said the cooling rods drop in and that's it, full shut down.

Think some scientists have been talking a load of bull over the years.

I guess as said before the control rods drop and the interaction between the fuel rods is stopped but the fuel rods themselves are so hot and they have elements constantly decaying inside them to keep heating them that without cooling they just melt.

Quote from: Serious on March 17, 2011, 00:32:14 AM
I thought these nuclear power stations were supposed to be 110% safe? They said the cooling rods drop in and that's it, full shut down.

Think some scientists have been talking a load of bull over the years.

You have one of the older plants and it first got hit buy a big ass earthquake and the rods dropped. Then you had a sh*t load of water hit the plant knackering the engines to sort the rods out again, and then you have things around the actual reactors blowing up and despite the sh*t that it is in it has not gone completely yet?

I would say that considering, its bad but it could have easily gone sooner if it was not mega safe.

*Heinsight? will be there now and I think Japan did well with the earthquake but did not expect the water so much.

You watch them though, you will have big ass tunnels made that will flip open to take the water in or something.