"Eunometic" wrote in message
om...
"Keith Willshaw" wrote in message
...

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.


The problem is that before this could happen the operating
chamber would have been flooded with fast neutrons.
Those physicists who examined the reactor were horrified
that anyone would build a reactor without control rods
or adequate shielding




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.


Correct



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).


You are assuming 100% efficiency, this is not attainable even now.
In fact refining the tailings of the old 50's enrichment plants is
a major source of enriched 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.


Quite so

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


No they had enriched considerable quantities of Uranium

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.


Germany never managed to enrich more than a few grams
of Uranium


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.

It was a little faster than the Lancaster but had a much smaller
internal bombload. Once you start hanging external stores
that speed advantage is gone.

Lancaster
Weight: Empty 36,900 lbs, Maximum Takeoff 68,000 lbs.
Wingspan: 102 ft 0 in.
Length 69 ft 6 in.
Height: 20 ft 0 in.
Performance:
Maximum Speed at 12,000 ft: 287 mph
Service Ceiling: 24,500 ft
Range with 14,000 pound load: 1,660 miles

He-177
Empty: 37,038lb. (16,800 kg)
Loaded: 68,343lb (31,000kg)

Performance:
Maximum (at 41,000lb.): 295mph (472km/h)
Service Ceiling: 26,500 ft (7080m)
Range with Fritz or Hs 293 missle: 3,107 miles

(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.


Indeed , compare and contrast with the 7000 Lancasters and
6,000 Halifax's built



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.


The Vulture was a failure pure and simple, the difference was
that the British air ministry didnt insist it be used anyway



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.


A 4.5 ton device needs a rather large parachute

Keith