**** Just Got Real in Japan

[rcpratt]

It doesn't get much more "worst case" than this. I still find it extremely unlikely.

 

[SagaLore]

You can turn it off, you just stop the reaction with enough neutron absorbers.

Right, that's also used to control the reaction and heat output. I don't know about the design of these particular reactors, but are they capable of taking more control rods right now? I was under the impression it was already a lost cause. You can't just wrap the reactor in absorbers; they need to go inside.

If they stopped supplying it with fuel, wouldn't it stop and cool down on its own at some point before it sunk through the earth?

They aren't supplying it with fuel. The reactor is the fuel.

 

[BoomerD]

I guess that's a good thing when I refer to SCRAM I'm talking to kids taking up my space. :biggrin:

Get off my deck!

 

[amdhunter]

Thank God everything good is made in China these days.

 

[herm0016]

they need to figure out a way to inject boron or something into the core. how about using vibration to break up the "crust"?

 

[bfdd]

why don't they just attack the thing from the bottom then? You're telling me there's nothing that can be done? that's lose talk and very un-human. personally i think they'll solve their problem and learn from their mistakes. it's quite sad so much fault is being laid upon nuclear technologies when almost all faults lay on human hands for poor decisions and upkeep/operation.

 

[cliftonite]

It doesn't get much more "worst case" than this. I still find it extremely unlikely.

What is the worst case for Japan if it were to happen? How many people would they need to evacuate?

 

[WelshBloke]

That lack of basic nuclear knowledge that is present in this thread is appalling. I sincerely hope my sarcasm meter has been damaged by something... :biggrin:

What, so your saying its not going to melt through the earth and dissolve Texas all the while spawning a race of super mutants and taking civilisation back to the stone age.

Is that what youre saying.

 

[vshah]

they need to figure out a way to inject boron or something into the core. how about using vibration to break up the "crust"?

yeah play some super bass up in there.

 

[Mark R]

Right, that's also used to control the reaction and heat output. I don't know about the design of these particular reactors, but are they capable of taking more control rods right now? I was under the impression it was already a lost cause. You can't just wrap the reactor in absorbers; they need to go inside.

Good thing boron (one of the most effective neutron absorbers) is soluble in water (as boric acid).

The trouble is, they've been pumping that into the cooling water to try to make sure that any nuclear fission is stopped. Of course, the other fact working in their favor is that power reactors run on lightly enriched uranium. LEU can only fission under a specific geometry, with a specific amount of interstitial water moderator. This configuration is unlikely to be achieved following a meltdown (but potentially, if enough fuel melted, and it was fresh enough, it could just maintain a fission chain reaction).

However, while the fission reactions can be controlled. The radioactive decay can't.

Following nuclear fission, the atom fragments are highly unstable and incredibly radioactive. The radioactivity is so intense, that the reactor is powerfully self heating. Take a fuel rod out of a reactor, shortly after shutdown, and it get red hot and burst into flames within a few seconds. Remember, the reactors melted down about 24 hours after they had been shutdown, after generators and cooling systems failed. Keeping the rods cool, requires huge amounts of water, and powerful pumps - typically, a reactor will have between 2 and 4 pumps of 5,000 - 10,000 hp each.

Even after 12 months for the radioactivity to decay, the rod will still get extremely hot (1000-1200 F) and crack, releasing the uranium/waste powder inside it. This heating is uncontrollable; the only thing you can do, is keep pumping water in to act as a heatsink.

If such a molten, self-heating mass manages to melt a narrow hole into the reactor building floor, then it may prove very difficult to cool it sufficiently to prevent it from continuing to melt through.

 

[The Boston Dangler]

@ rcpratt

do the containment floors have a means of active cooling?

 

[Subyman]

Ugh, more bloggers trying to armchair engineer. I've heard nothing from the ANS or my professors (I'm a nuke grad student) about any further developments. I'll get a friend to translate that report for me later in the week. Every time I hear "China Syndrome" I think of Michael Douglas, which is pretty funny.

 

[busydude]

^^ Student of SIU?

 

[darkswordsman17]

It is officially more serious than 3 Mile Island, but not quite as serious as Chernobyl.

Though....maybe it will out-serious Chernobyl?

The thing is, Chernobyl is an ongoing problem still. They are finally getting around to addressing long term containment, but the whole thing has been messed up.

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

 

[rcpratt]

Tepco announced that the reactors are in cold shutdown.

 

[rasczak]

Tepco announced that the reactors are in cold shutdown.

meaning?

 

[rcpratt]

Atmospheric pressure and <200F. It's been that way for awhile, though. Just kind of a sign of stability.

 

[WelshBloke]

Tepco announced that the reactors are in cold shutdown.

Thats because all the nuclear material is currently heading for Texas.