Scary Nuclear Stuff From Canada!

The first 3 paragraphs tell the story.



http://nativeunity.blogspot.com

The ACR (Advanced Candu) reactors were designed to have a "negative void coefficient of reactivity" (VCR). The U.S. Nuclear Regulatory Commission USNRC concluded the opposite. Under certain accident conditions, the ACR reactors could have a "substantially" POSITIVE VCR. As we said, a negative VCR is good and a positive VCR is bad. Since nobody has ever built an ACR, the two groups of experts, AECL (Atomic Energy of Canada Ltd.) and USNRC, disagree. There is no analysis except on paper and using computer models. Both don’t understand what is going on in the core of an ACR reactor

So under certain accidental conditions they produce the material for A-bombs? So this is a dual use technology which can slip up and make nukes? I hope to God somebody is on top of this, but I'm confident that they are. Nevertheless, this points out some of the serious risks in nuclear energy. I think a future without it is the way to go.

... when the fluid bathing the core heats up and starts to form voids -- aka bubbles.


In a reactor design producing a negative void coefficient, the voids will cause the chain reaction to slow down. This does help the reactor self-protect against overheating and meltdown.

In a reactor design producing a positive void coefficient, the voids will cause the chain reaction to speed up. The result is a reactor that can get away from you very fast, and that is completely reliant on external safety systems.


The Chernobyl reactors had a positive void coefficient as one of their serious design flaws, and this played a role in producing the conditions that created the meltdown.

However, NO reactor design in current commercial use is meltdown-proof. Three Mile Island's reactors were designed for a negative void coefficient -- and look what happened there.

So under certain accidental conditions they produce the material for A-bombs? So this is a dual use technology which can slip up and make nukes? I hope to God somebody is on top of this, but I'm confident that they are. Nevertheless, this points out some of the serious risks in nuclear energy. I think a future without it is the way to go.

You're thinking of a breeder reactor, perhaps? That's different. Breeder reactors can be designed with a negative void coefficient, but I still wouldn't trust one. They're kind of notorious, safety-wise.

Last night, I thought it said that the undesired reaction could produce the weapons grade stuff...But I was also piss drunk. Thanks for the clarificaition....Still scary stuff.

There are 4 of those on the earth.

1)Urbana in Ill,
2)Univ of Wisconsin,
http://www.dailykos.com/story/2006/11/28/15328/187/145/275456
3)Japan,
4)Santa Fe NM.
http://www.emc2fusion.org/

Lots of people have built IECs. So far, they're net consumers of energy. Even if reactor designs involving IECs ever became commercially viable, wouldn't the technology just create a nice, easy way for Bad Guys to make plutonium?


:think:

Folks been making Pu since the 1940's.

The current IEC devices burn DD Fuel, DD requires less power input to fuse. THis is good for research. I feel that commercially viable fusion will occur with boron fuel, this is aneutronic fusion. No neutrons. But for research Boron devices need to be larger and more powerful.

So if by 2050 IEC or Polywell fusion is well on its way to replacing oil & coal, its likely to be the Boron devices that create no neutrons.

What we need to watch is the ITER project, that sucker looks to dovetail into weapons programs. Bad. It is very unlikely the ITER will lead to anything worthwhile. Nature doesnt fuse in a torus. Tokamaks are just the wrong shape. They wont ever lead to power generation.