[AR] Re: arocket Digest V7 #93
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 14 May 2019 00:39:48 -0400 (EDT)
On Mon, 13 May 2019, Christopher Manteuffel wrote:
the entire V-2 project cost less than just the K-25 (Gaseous Barrier
Diffusion) plant alone...
Well, to put that in context, the gaseous-diffusion work and the K-25
plant in particular are estimated to have cost around half the entire
budget of the Manhattan Project. Uranium isotope separation is hard,
especially when it's done using UF6.
The Manhattan Project operated at an economic scale that is difficult to
comprehend, and it is impossible for me to envision the Nazis meeting
that challenge.
Bear in mind that a serious German atom-bomb project wouldn't have had to
follow the Manhattan Project's blank-check-emergency "if there are three
ways to do it and we don't know which one will work, do *all* of them!"
approach. The M.P. was driven, above all else, by fears of a German bomb,
so success ASAP was imperative and cost very much secondary. Whereas the
Germans simply didn't take the possibility of competition seriously -- the
interned German physicists were flabbergasted when they heard about
Hiroshima -- so they would not have felt such panic, and would have
focused on the most promising options.
And indeed, what little there was of a German bomb project had quickly
written off uranium isotope separation as hopelessly difficult, and
focused on building reactors to (among other things) breed plutonium.
That alone would have cut the serious project's budget requirement by a
factor of two or more.
(The Germans would have told you that the difference was much larger, but
they were underestimating the difficulties of plutonium chemistry.
Nobody then realized that the actinides are a separate subsection of the
periodic table, analogous to the rare earths, all with very similar
chemistry -- they thought of plutonium as being in the same column as
rhenium, with enough chemical differences from uranium etc. to make
plutonium separation a relatively modest problem. Jeremy Bernstein's book
"Plutonium" has a good discussion of this, and is generally well worth
reading for its comments on the technical history of the bomb projects --
turns out that on this topic, it really makes a difference when the book
is written by a physicist rather than a historian or journalist.)
You might find a German atomic bomb impossible to envision, but I'd say
it's noteworthy that *nobody* on the Manhattan Project seems to have
agreed with you.
Henry
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