Earthquake off Japan

[Dartzap]

Reactor 4 is now on fire (again?)

Looks nasty....

[bz249]

Question: I understand that a reactor has two water-cycles: one that is purely internal and what actually meets with the reactor itself. This water only leaves the power plant in a controlled manner (ie, as nuclear waste)
The second only indirectly meets with the first and it is what is actually used to generate power. This water leaves the plant regularly.

Do I understand correctly that essentially the first water-cycle is the one that has been blown up with reactors 1 to 3?

No, what you thought about is a PWR type reactor (pressurised water) which is indeed the most popular design. The Fukushima on the other hand is a BWR (boiling water) type, where the directly generated steam drives the turbine. Both have certain advantages and disadvantages.

http://en.wikipedia.org/wiki/Boiling_water_reactor

http://en.wikipedia.org/wiki/Pressurized_water_reactor

[Julhelm]

So how much can this uranium fire contaminate if they are unable to put it out? Will it be like the Kysthym disaster?

[The Duchess of Zeon]

So how much can this uranium fire contaminate if they are unable to put it out? Will it be like the Kysthym disaster?

Maybe if all three fuel pools go up with full loads and burn uncontrollably for weeks and full exposure to the atmosphere.

[Tribun]

TEPCO reported that this new fire is the result of the first one not being put out properly. The heat is said to be so strong that it is very difficult to extinguish the fire.

[Sea Skimmer]

If they can't restore cooling to the fuel pond then logically it should just keep reigniting from the ever continuing heat buildup until all fuel is consumed. I think they need to just bite the bullet and setup a couple aerial water cannon trucks to dump water into the pond. No reason why they couldn't be left running alone for hours, with people only coming back out in APCs to refuel them. However that fuel isn't going to cool off for months...

[Tribun]

Well, the fire is out for the moment. However, before that it according to reports destroyed all electrical systems within the building, especially all controls of the coolant system. So if they don't find a way to get water into the pond, they have a problem.

[CaptainChewbacca]

Maybe I'm too accustomed to disaster movies, but this thing is near the ocean. How about a huge fucking ditch full of water, or several hundred hoses?

[Tribun]

Other news besides the damage done by the fire:

TEPCO said that they estimate that 70% of the fuel rods of reactor 1 are damaged, as well as 33% of the rods of reactor 2. They did not exactly say what they understand under "damaged", but this seems to be confirmation that these two reactors are reduced to contaminated scrap.

[Broomstick]

Well, it DID get hit with a 30 foot wall of water, that was sort of the problem in the first place...

More seriously - I don't know. They ARE taking water from the ocean but I'm not sure of the mechanism or what obstacles there might be between the water and the offending firepit. It would be ironic that if a seawall that wasn't quite tall enough to stop the tsunami is too high to easily allow the sea in as cooling water... but I haven't a clue if that's the case.

[The Duchess of Zeon]

Maybe I'm too accustomed to disaster movies, but this thing is near the ocean. How about a huge fucking ditch full of water, or several hundred hoses?

The problem is the sustained exposure. My preference would be for simply grabbing the rods and dumping them into the sea. Huh. I just found a use for a heavy-lift UAV.

[CaptainChewbacca]

Maybe I'm too accustomed to disaster movies, but this thing is near the ocean. How about a huge fucking ditch full of water, or several hundred hoses?

The problem is the sustained exposure. My preference would be for simply grabbing the rods and dumping them into the sea. Huh. I just found a use for a heavy-lift UAV.

Throwing control rods in the sea? If you thought the controversy over whaling was bad before, Greenpeace would shit a brick house.

[Uraniun235]

That's already a given at this point, Chewie.

[The Duchess of Zeon]

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

EDIT: Much to my surprise, it apparently is a flame retardant. OK, so that's retracted.

[Fingolfin_Noldor]

Throwing control rods in the sea? If you thought the controversy over whaling was bad before, Greenpeace would shit a brick house.

Who in Japan honestly gives a shit about what Greenpeace thinks?

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

I thought they were already dumping neutron moderators in in addition to seawater.

[The Duchess of Zeon]

Throwing control rods in the sea? If you thought the controversy over whaling was bad before, Greenpeace would shit a brick house.

Who in Japan honestly gives a shit about what Greenpeace thinks?

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

I thought they were already dumping neutron moderators in in addition to seawater.

Into reactors. Not into the fuel pool. The fuel pool should not be having nuclear reactions occur in it--it should just be generating heat from decay.

[weemadando]

Dropping the encased rods down into the hundreds of metres deep silt in the middle of a stable abyssal plain is a realistic option though.

[Duckie]

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

Not really, Duchess. Boric acid has a red rating of 0 on its NFPA square and I would not be surprised if it were an effective fire retardant- most boron compounds are.

[Fingolfin_Noldor]

Into reactors. Not into the fuel pool. The fuel pool should not be having nuclear reactions occur in it--it should just be generating heat from decay.

Well, the fuel pool caught fire so...

[The Duchess of Zeon]

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

Not really, Duchess. Boric acid has a red rating of 0 on its NFPA square and I would not be surprised if it were an effective fire retardant- most boron compounds are.

Blame your chemist girlfriend for that. She initially said it wasn't a flame retardant and then reversed herself when I asked her before posting. *snarks*

[SCRawl]

I was a little late in getting this post approved. I thought that it deserved its day in the sun on the most recent page of this discussion. Please make our fresh meat new member feel terrified welcome.

I have a question that some of you might be able to answer.

What would have happend if nobody would have done anything?

I mean: reactor shuts down, cooling fails immediately after and for some reason no staff is around to handle things (lets say its the Stephen King Flu).

From what I understand any remaining water turns to steam and meltdown starts. Would at that point, whithout venting, the pressure rise high enough do crack the containment (primary or all of them)? If so would this happen explosively or more like valves popping off and the reactor "venting itself"? Then eventually the puddle of molten fuel would melt through the bottom of the pressure vessel.
Would the residual heat, whithout any cooling, be enough to get through the floor? The decay heat generated is finite so it should be possible to determine a floor structure thats thick and wide enough to catch the molten fuel for sure, right?
Have the done that?

I mean, that way the reactor would be essentially fail safe, even when everyone turned off the lights and left, if you only install some ordinary passive over pressure valve.

Or is the energy from the decay whithout cooling so insanely great that it's impossible to put enough concrete under the floor?

I assume it's not that simple, so what did i miss?

[Duckie]

There is either a serious risk of a criticality accident or one has in fact already occurred at No.4--TEPCO is claiming they are going to be using boric acid dumped in very large industrial quantities into Reactor Building No.4 as a "flame retardant". Boric acid is flammable; the claim is bullshit to cover up the actual danger or occurrence. They need a neutron moderator in that building, and that is not good at all.

Not really, Duchess. Boric acid has a red rating of 0 on its NFPA square and I would not be surprised if it were an effective fire retardant- most boron compounds are.

Blame your chemist girlfriend for that. She initially said it wasn't a flame retardant and then reversed herself when I asked her before posting. *snarks*

that's what you get for asking a statistician for chemistry advice

[Sea Skimmer]

Other news besides the damage done by the fire:

TEPCO said that they estimate that 70% of the fuel rods of reactor 1 are damaged, as well as 33% of the rods of reactor 2. They did not exactly say what they understand under "damaged", but this seems to be confirmation that these two reactors are reduced to contaminated scrap.

Yeah, most like that it is the case. It is possible for fuel rods to be damaged without extensive melting though, the cladding could deform for example but not slough off. This would be very optimistic thinking and only be possible if the fuel rods were exposed for no more then a few minutes.

[Sea Skimmer]

The already shutdown no.5 reactor is now being reported as having cooling problems. However they have also said that a generator that still works at no.6 reactor can be cross linked to restore cooling flow to no.5. Even shutdown you've got the same problem inside a reactor that they are having with the no.4 spent fuel pool. That stuff stays pretty damn hot for months.

No.4 reactor may be on fire a (third?) time ; something is burning at the plant on the video feed.

[Vaporous]

FUKUSHIMA, Japan — Workers at a quake-damaged atomic power plant suspended operations and evacuated Wednesday after a surge in radiation made it too dangerous to remain there, dealing a setback to Japan’s frantic efforts to stem a nuclear crisis.

"All the workers there have suspended their operations. We have urged them to evacuate, and they have," Japan's chief cabinet secretary, Yukio Edano said, according to a translation by NHK television.

Edano said that a surge in radiation Wednesday morning meant workers were unable to continue even minimal efforts at the stricken nuclear plant.

About 45 minutes later, though, radiation levels near the plant came back down, he said. It's possible that evaporation from reactor No. 3 may have caused the temporary surge, Edano said, although that can't be immediately confirmed.The cabinet secretary added that there was no need to broaden the overall evacuation radius around the nuclear complex.

via MSNBC.

So for at least 45 minutes, no one was manning the plant, and it is possible that no one is there right now.

If confirmed, there's a pretty long list of reasons why we're in trouble here.