[extropy-chat] Nuke 'em

[Samantha Atkins]

On Oct 26, 2005, at 9:53 PM, John K Clark wrote:

>
> Samantha Atkins Wrote:
>
>
>> I don't see how that is true in any meaningful way after
>> reading this.  Please show me how a pebble bed reactor
>> always makes plutonium or is even well suited for such use.
>>
>
> If you place Uranium is a sea of neutrons, and that's what a  
> reactor is,
> then like it or not, commercial reactor or military you're going to  
> make
> Plutonium. Indeed in the very article you mention I found this:
>

Is this also true of Thorium based reactors?  The article points out  
the stickiness of getting weapons grade plutonium also.  It is not  
quite enlightening to simply say every reactor produces plutonium and  
thus is a problem for anti-proliferation.

> "Pu-239 is normally manufactured in nuclear reactors. If U-238 is  
> exposed to
> neutron radiation, the nuclei will occasionally capture a neutron,  
> becoming
> U-239. This happens more easily with fast neutrons than with slow  
> neutrons,
> although both can be used. The U-239 rapidly undergoes beta decay  
> to give
> Np-239, which rapidly undergoes a second beta decay, giving Pu-239. "
>
> And it says to make bombs the Pu- 239 should not be polluted with  
> Pu-240 and
> your article then says this:
>
> "A nuclear reactor that is used to produce plutonium must therefore  
> have a
> means for exposing U-238 to neutron radiation, and for frequently  
> rotating
> this U-238"
>
> Since one of the claims of fame of the pebble bed reactor is that  
> you can
> refuel without shutting down it would seem to me to be especially  
> suitable
> for making weapons grade Plutonium

Simply removing the pellets periodically is certainly not enough to  
enable efficient weapons-grade plutonium production.  Also it is  
possible to run a pebble bed reactor starting with plutonium rather  
than uranium.  If this can be done with non-weapons grade plutonium I  
wonder if this could be a reasonable  choice.

- samantha