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.


Quite right. Each set of that (fission-fusion-fission) is called a
'stage' of the weapon. Most nuclear weapons these days are two stage
weapons, where each stage uses radiation pressure from the preceding
stage to compress the 'pit'. It is possible to design weapons with
large numbers of stages, but it becomes something of a waste of time
after a few stages. The most stages we've actually used in a weapon
is three. The most stages in any modern weapon is two. It makes more
sense to build a pair of two stage weapons and spread them around
rather than a single three or four stage weapon that wastes most of
its energy.


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.

I think you are confusing radioactivity for explosive yield as far as
the danger of cobalt bombs are concerned.


I don't believe anyone ever built a cobalt bomb. Turns out that a
fission-fusion-fission bomb is damned near as dirty while having the
advantage of not screwing things up for centuries, so there was no
point.



Since there is no place to test a cobalt bomb safely, it is unproven
as to the outcome of detonating a cobalt bomb. But nobody would want
to try it.


Untrue. See cited reference below, the UK's Operation Antler/Round 1
tested a bomb using cobalt salts as a radio chemical tracer for yield
estimation.

See:

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

Dave

[1] https://en.wikipedia.org/wiki/Thermonuclear_weapon

--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden