On Monday, November 19, 2001, at 12:15 PM, baptista@pccf.net wrote:
exactly right Ken .. as i said before to Tim May - propaganda is the key. Example - antrax theatre.
i must admit i'm warming up to Tim May's tall pipe means of attaining critical mass - much easier then playing with explosive and timing devices - my only question is do our experts see a problem with that means of delivery?
As I made clear in my post, it's not _my_ idea. It's one of the standard "basement nuke" proposed designs. I don't particularly care whether "nuclear terrorist" is added to my dossier by the agents in place here on this list, or by other readers, but I don't want to get credit not due me. Also, I'm not a nuke designer and don't plan to answer questions about neutron crossections, thermal excursions before criticality, etc. I will mention that Ken Brown's "many pieces along the length of the pipe" is the worst way to do this: it buys nothing over the two pieces approach and it causes all sorts of problems with the pieces getting too hot as they come together on the way down. (For example, the penultimate chunk falling toward the ultimate chunk...likely to already be melting and spraying molten U-235 inside the pipe. Just another fizzle. And fizzles are not very interesting, for reasons I stated. A way too expensive way to spread mere radiological terror, which could be done much more cheaply and easily by taking spent fuel rods and blowing them up, or just by grinding up spent fuel rods or other nuclear waste and then dumping it out of a plane over a city.) By the way, some calculations are still needed (by basement nuke designers) on what the closing speed needs to be to get a reasonable chain reaction yield. The rough calculations I saw said that a fall from 40 feet, with good tamping behind and all on sides of the masses, would work. But it would be easy enough to accelerate the falling mass even more. An explosive charge, maybe even a rocket motor. (The Little Boy nuke was of course a "gun" design. The maker of a basement nuke has the advantage of not having to be portable in even the sense that the Hiroshima (Little Boy) and Nagasaki (Fat Man) nukes were portable-with-a-big-bomber. The basement nuke can be surrounded by lots of shielding (to foil N.E.S.T.), can use lots of tamping material, and can be wasteful in use of fissionables.) --Tim May "Extremism in the pursuit of liberty is no vice."--Barry Goldwater