[ RadSafe ] RE: neutron initiaition of nuclear weapons

Shawn Hughes (Road2) srh at esper.com
Fri Jun 29 20:12:43 CDT 2007


Don't know if this subject has been put to rest or not, but I can speak with
some authority on this topic. Problem is that this is an Unclassified,
international list. Anyway, it is unclassified, that the 1561 "Fat Man"
assembly used a beryllium shape coated in a certain manner with 50 curies of
Polonium-210. The half-life being what it was, it required periodic
replacement as a limited life component. Physical crush was the mechanism of

This is no longer used in any NATO weapons system. I cannot answer whether
or not legacy systems are or are not currently intrinsically built (no In
Flight Insertion), as that is borderline CNWDI.

For more, google Christy pit, Urchin, or Screwball.



Hi, Franz.

Are you sure it isn't Pu-Be rather than Po-Be?  I am sure that one could use
Po-210 and make a compact source with high output, but the 140 day half life
means that you would have to use it quickly, before it decayed too much.
That doesn't sound too good for nuclear weapons, that usually are left
inside their delivery systems for many years at a time.  Pu-238, on the
other hand, has a really nice half life for doing all sorts of things where
you want to balance specific activity and longevity.  

Shawn R. Hughes
Special Projects Consultant
near Oak Ridge, Tennessee
(865) voice
srh at esper.com primary email
www.shawnrhughes.com fledgling webpage
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