[LAU] OT: metal, money, changes, bleg

[Erik de Castro Lopo]

Patrick Shirkey wrote:

> So just to make sure I am correct here... All nuclear weapons require an 
> assisted explosion?

Yes, you need both high heat and high pressure to force the fissile
material into the required chain reaction.

> It's categorically impossible for Plutonium-239 to 
> become critical without assistance from an explosion of some other fuel 
> or high energy source?
> 
> You don't have super heated Pu-239 actively being created in a semi 
> critical chain reaction. If it gets unstable there is not enough neutron 
> flux to make baby go boom.

As explained here:

    https://secure.wikimedia.org/wikipedia/en/wiki/Criticality_accident

there have been a number of criticality accidents, but they always
create so much heat that the fissile material expands and the conditions
cease to be critical.

Erik
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Erik de Castro Lopo
http://www.mega-nerd.com/