[ RadSafe ] Testing bombs

[Geo>K0FF]

Hi Jim, my semantics are correct, if not popular. Whoever said "being 
popular doesn't make it right"?
I cite Cosmic Rays (not rays at all), Pencil LEAD ( not lead at all), but 
the masses like things simple.

Since this is a technical discussion group, perhaps we should refrain from 
the popular jargon and speak technically.
Just an opinion.

The distinction you make concerning the energy in a nuclear bomb coming from 
binding energy is quite correct. In  a nuclear bomb, the E=MC>2 matter to 
energy conversion has to do with the energy deficit (also related to binding 
energy) when an atomic nucleus is formed. The sum
weight of the protons and neutrons in a nucleus is less than the intrinsic 
weight of the protons and neutron individually. It is this mass
difference, not the mass of the protons or neutrons that enter into the 
release of energy by conversion of matter to energy.

Protons can convert to neutrons, and neutrons can become protons in normal 
nuclear reactions, but they always remain.
Photons can turn into matter in the "pair production" reaction, and matter 
can turn into photons in the positron annihilation reaction.

George Dowell
New London Nucleonics Lab
GEOelectronics at netscape.com




----- Original Message ----- 
From: "Dukelow, James S Jr" <jim.dukelow at pnl.gov>
To: "Steven Dapra" <sjd at swcp.com>; <radsafe at radlab.nl>
Sent: Monday, June 30, 2008 12:52 PM
Subject: RE: [ RadSafe ] Testing bombs



Nobody has really answered Dapra's original question, which has some 
contemporary relevance.

The difference between the U-235 bomb and the Pu-239 bomb is that the Pu-239 
was contaminated with other isotopes of Pu that have significant spontaneous 
fission rates.  If the process of assembling a critical mass was "slow" 
(say, tens of milliseconds), there would be a significant probability that 
the assembling critical mass would be "pre-ignited" by stray neutrons from 
the spontaneous fissions, leading to a lower yield -- a "fizzle".  The 
answer was to used carefully designed explosive charges to assemble the 
critical mass very quickly.  Until Trinity, the implosion design was 
theoretical and the test was need to give confidence that the weapon would 
work.

All of this is very nicely described in The Los Alamos Primer, by Robert 
Serber.  It is the annotated notes of the lectures that Serber gave to 
physicists and other arriving at Los Alamos to participate in the Manhattan 
Project.  The notes were published in 1992 and are currently available from 
Amazon.

This problem did not exist with U-235 and the physicists were quite 
confident it would work the first time.

The current relevance is that Iran, and earlier, North Korea is/were using 
both plutonium production and uranium enrichment to pursue nuclear weapon 
capability.  The weaponization issues remain with plutonium weapons and 
uranium weapons remain simple to implement once sufficient fissile material 
is available (although "deliverable" weapons may be more of an issue).

Dowell's linguistic distinction between nuclear (fission and fusion) 
explosions and atomic/chemical explosions is not standard usage, but is 
reasonable.  The nuclear weapons involve the release of the nuclear binding 
energy of the atomic nucleus, while chemical explosions release the chemical 
binding energy of the electron orbitals.

Hanford's weapons mission is over and it is probably not to hard to arrange 
tours of most of the facilities, although I haven't tried to do it.

Best regards.

Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow at pnl.gov

These comments are mine and have not been reviewed and/or approved by my 
management or by the U.S. Department of Energy.

-----Original Message-----
From: radsafe-bounces at radlab.nl on behalf of Steven Dapra
Sent: Sat 6/28/2008 8:49 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Testing bombs

June 28, 2008

>From time to time I have read that one of the Hiroshima and Nagasaki bombs
had to be tested before it was used, and that one did not --- that the
engineers were so certain the latter bomb would explode that they didn't
bother testing it.  I also read recently that hydrogen bombs must be
tested.  Of these three types of bombs, which ones must be tested, and
why?  For the one that did not have to be tested, why not?  (I don't have
any bombs I want to test, I am merely curious.)

Steven Dapra
sjd at swcp.com

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