Re: Why would high grade aluminum be used in nuclear weapons?

Ginkgo, 

Welcome to my world.  You are correct in your research.  The higher the 
purity of the U or the Pu, the better the bomb.  Mixing in junk makes it 
not work right or worse yet, it doesn't detonate and just spreads a fine 
layer of U dust over everything.  This is yet another marvelous example of 
lousy reporting done by a technical illiterate.  Aluminum makes a lousy 
radiation shield for a nuke but might make a nice outer bomb casing that 
housed the shielding (usually an iron alloy), the pit and the firing 
electronics. What "high grade" has to do with this I have no idea.  I've 
seen a few Russian warheads and the term "high grade" would have to be 
applied loosely.  Besides, if we're talking about Palestinians and if it 
was any real security threat, rest assured that Israeli Defense Forces 
would make short work of them.  

Fear not, young scientist.  Reporters are just awful.  I recommend avoiding 
them at all costs unless you have a professional PR person with you.  
(Personal experience.) Good luck and keep fighting the good fight for the 
truth.  (Someone has to.)  

Scott Kniffin
Senior Engineer, Orbital Sciences Corporation
NASA Goddard Space Flight Center
Office of Systems Safety and Mission Assurance
Radiation Effects and Analysis Group, Code 562