"Keith Willshaw" wrote in message ...
"Eunometic" wrote in message
m...
(Denyav) wrote in message
...
So now I've answered that question, maybe Denyav can answer why he
thinks
the Manhattan Project went from "failure" to success in days, whilst
creating a non-US implosion device took years? (Somehow I expect he
won't.)

I am pretty sure if somebody had offered to any non-US country an almost
completely assembled plutonium bomb including a designed and Made in
Germany
triggering syetem,any non US country would become a nuclear power
overnight and
moreover the Charlatan who who took triggering system from Germans would
be
hailed as a national hero who solved the seemingly insolvable triggering
problem at the last minute.

BTW when UK started producing plutonium? I guess 7 years behind Third
Reich?

Most of the German atomics researchers ended up under Soviet control.
They published a great deal of work under Russian sounding pseudonyms
because Stalin found that the prominance of German names in the
Russian leterature was politically embarasing. They has a reputation
for thorough and hard work, through somewhat unimaginative, that
contributed greatly to the Soviet nuclear effort.

The standard knowledge is that the Germans made a test reactor that
was 'pre-critical': They lowered an array 1 inch cubes of uranium
suspended from chains into a shielded tank of heavy water. The
neutron population increased by a factor of 7 within the 'pile' due to
fissioning induced by a small neutron source placed near the pile.
From this they correctly deduced that they would need to increase the
linear dimensions of their 'pile' by 50% for the reaction to become
self sustaining. This puts the Germans in late 1944-1945 at about the
level the Allies were at 1942. There were no control rods on this
test device: control was to be by raising or lowering the uranium
array of draining the heavywater.


There was no radiation shielding either. Achieving criticallity
would have killed the researchers and likely caused a nasty
nuclear accident as the reaction vessel boiled dry

The 'reactor' was sunk in a pit in the ground, lined with thick
concret and graphite and submerged in heavy water. The Uranium cubes
were lowered slowly via a hoist and observed via remote
instrumentation from a great distance. The reactors was not designed
to opperate for any length of period: merely to establish criticallity
parameters. An increase in neutron population indicating criticality
would have immediatly led to termination of the procedure by withdrawl
of the fuel assembly or draining of the moderating heavy water.




In some areas they were ahead. They worked in the direction of using
ultra high speed electronically switched centrifuges to stratify
uranium hexaflouride gas to enrich unranium and managed to make a few
milligrans of uranium at 5% or so. This was on only a single
centrifuge and a multilevel array would have been required.

One thet held together for more than a few minutes
would have helped too. Fact is the Germans didnt have
the materials required to resist Uranium Hexafluoride.


Which are the same refractory and corrosion resistent metals required
to make jet engines.



Centrifuges are a better way to enrich unranium and this has become
the modern method. It was in fact perfected by ex German researchers
in the Soviet Union and then when they were realeased in the West.


Not quite. The first soviet centrifuge pilot enrichment plant was
run at Sverlovsk-44 in 1957 but it didnt produce significant
amounts of enriched material until 1964. Prior to that the USSR
used gaseous diffusion enrichment.

At the same time parallel developments were going
on in Germany, the Netherlands and Britain. The
first centrifuge in the UK was assembled in the 60's
These companies joined together to form Urenco

The allied approach of breeding plutonium or building massive gaseous
diffusion plants to enrich natural unranium are not required to make
an atomic bomb.


Plutonium is however the most likely unless you have
large stocks of Uranium

AFAIK see you need 12kg of U235. With a proportion of 0.7% that means
each weapon requires about 100%/0.7% x 12 = about 1680kg or raw
uranium. Say 2.5 tons. Assuming the Germans needed more we are
left with a need for maybe 5 tons per bomb. Say 3 test devices and 1
attack unit and 2 backups. A total requirement of about 15 tons.
(less than a 1 meter square cube of uneriched uranium).


One of the great 'frauds' that was used to justify WMD claims against
the Regime of Saddam Hussein related to the use of lightweight high
strength aluminium tubeing which was supposedly for the fabrication of
these centrifuges but turns out to have been for "Katuysha (little
Kate) unguided bombardment weapons.


Indeed. we found out after the 1991 war that Iraq was using
gaseous enrichment.

Because centrifuges require excellence in engineering.

Iraq wasn't 'using gaseous diffusion' as much as toying around with
experiments.

It is a measure of Germany's technical capacities that Iraq was barely
able to reproduce Germany's technolgy in rocketry and uranium 50 years
later.


The Germans must have been reasonably sure of success eventualy as
they set aside a Heinkel He 177 Grief to deliver such a bomb.

The Heinkel Grief was a rather unsuccesful aircraft that was only
set aside in the sense that it was produced in rather small
quantities.

It's performance was more than adaquet and significantly better than
any British 4 engined bomber though not up to the standards of the
turbo supercharged and pressurised B29. (A Heinkel He 274 did fly)
Being Germanies first heavy bomber it would be expected to have
teething problems especialy as it was produced in quantities of only
1200 of which the final A5 model made up 860.

It was produced 4 major series from He 177 A1 through to He 177 A5.
(no pressurised A4) The final versions achieved a considerable
improvement in reliabillity and performance. The first version earned
the nickname "Reich Fuerzeuge" (Empire Cigarett Lighter) because the
coupled engines cooling issues gave them a propensity to burn. Goering
said that it was retired because of its prodigious use of fuel. When
you have trouble putting up Me 109s and Fw 190s on 90 minute missions
you don't put resources into a machine with 6 flight crew and 4 really
big engines, a 15 ton fuel load. Designes for a 4 engined versions
known as the He 177B were ready (and flown as the He 274) powered by
conventionaly distributed engines. (BMW 801 or Junkers Jumo 211).

It should be known that the Lancaster was developed from the
Manchester by a similar process when the RR Vulture was stressed
beyond its capacity to keep the overweight Machester flyable.


It would not have been capable of carrying a
first generation nuclear device and escaping the blast

Release from 20,000 ft would seem more than adaquete especialy if it
was a 10 kiloton instead of 20 kilotosn blast. However the usual
answer is to retard the bomb with some kind of parachute.




Keith




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