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Old January 7th 17, 06:45 AM posted to sci.space.history
Fred J. McCall[_3_]
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Default The Space Race was about Power Projection - Miles O'Brien

David Spain wrote:

On 1/6/2017 11:15 PM, David Spain wrote:
On 1/6/2017 9:31 PM, Scott M. Kozel wrote:
On Thursday, December 29, 2016 at 10:10:35 PM UTC-5, Fred J. McCall
wrote:
"Scott M. Kozel" wrote:

Likewise nobody has ever tested a cobalt bomb. A cobalt bomb
would blow up one third of the world, so there is no place to
safely test one.

Don't be silly. The cobalt adds nothing to the explosion.

The way it was explained was that a large hydrogen bomb is encased
in a cobalt casing, and when it detonates a fission-fusion-fission
reaction takes place, and the explosion is so large that it would
blow up one third of the world.

In the past war planners worked scenarios such as "which city will
we blow up", or "whose country will we blow up". With a cobalt bomb
the question would be "whose one third of the world will we blow up".


A short off-topic post:

Fission-fusion-fission is the normal process for a hydrogen bomb to
begin with. The majority yield of an H-bomb of the Ulam-Teller design[1]
is derived by fast fission of its natural Uranium tamper jacket of U238
because of bombardment by high energy neutrons from the fusion of
lithium deuteride acting as the solid fusion fuel.

Cobalt bombs were designed for enhanced radioactivity or "dirty" bombs
because of the enhanced half-life of the Co-60 isotope (~ 5 years)
produced by "salted" bombs. It was viewed by war planners as too long to
remain safely sheltered in a bomb shelter and yet still short enough to
produce lethal amounts of radioactivity as a ground contaminate as it
decays to harmless nickel.


Also just FYI the fission cross section for Co-59 (naturally occurring
Cobalt) is too small to be better than U238 (natural Uranium) in support
of fast fission as a bomb fuel. See the table entitled Typical Cross
Sections in this link for the relative fission cross-sections (in barns)
of various elements:

https://en.wikipedia.org/wiki/Neutron_cross_section


He should also be aware that iron is a low energy point in the
periodic table. Elements significantly heavier than iron can produce
energy via fission because they will produce pieces heavier than iron
but closer to it than the original fissionable material, energy, and
spare neutrons. Very light elements can fusion, producing products
closer to iron and also some energy. Trying to fission (or fusion)
things close to iron (like cobalt) CONSUMES energy if you could
succeed at it, so what you get from pelting cobalt with neutrons is
merely a different isotope of cobalt (transmutation from stable Co59
to radioactive Co60).


--
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