Re: Fading Extropy: More threats.

From: S.J. Van Sickle (sjvan@csd.uwm.edu)
Date: Mon Oct 14 2002 - 17:11:49 MDT


Sorry, subject got left off somehow....resend...

On Mon, 14 Oct 2002, Robert J. Bradbury wrote:

>Interestingly it does beg an answer to my earlier question
>as to whether there is a material other than U-235 or Pu-239
>that can make a nuclear weapon with less material. U-235
>decays releasing an alpha particle with ~4.7 MeV while
>Pu-239 decays with an alpha particle with 5.2 MeV. Other
>isotopes like Am-241;-2433 (alpha, 5.4-6 MeV) and Cm-242/3/4/5/6/7,
>alpha, 5.3-6.2 MeV) would seem to be likely candidates.

Carey Sublette is the internet nuclear weapons guru. His FAQ is in many
places, this is the most recent version I could find quickly:

http://nuketesting.enviroweb.org/hew/Nwfaq/Nfaq0.html

The materials section will answer your question in detail. The short
answer is that there is no weapon material with appreciably smaller
critical mass than plutonium:

http://nuketesting.enviroweb.org/hew/Nwfaq/Nfaq6.html

Radioactive decay has no bearing on weapons use, other than high activity
is detrimental to design due to cooling issues for weapons in storage and
transit and high neutron activity causes predetonation. Relatively stable
materials are preferred.

The Federation of American Scientists used to host the FAQ, but dropped it
after 9/11. What respect I had for the organization went with it.

sjv



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