nazi nuclear research - safety in engineering

1

Jim Thomson

www.safetyinengineering.com

Nazi nuclear research: Why didn’t Hitler get the Bomb?

Nazi nuclear

research

2

1. The German project and a brief comparison

with the Manhattan and V-weapons projects

2. German project technical achievements and

failures

3. Political and organisational factors

4. Motives, ethics, competence and honesty

5. Postscript: The lunatic fringes

Jim Thomson www.safetyinengineering.com

1. The German project and a

brief comparison with the

Manhattan and V-weapons

projects3


1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s

Discovery

of fission

Germany

1938/39

First German

government

interest April

1939 First sub-

critical pile,

Autumn

1940

Einstein letter

to Roosevelt

August 1939

Frisch-Peierls

memorandum

March 1940

February 1942: Presentation to senior Government officials. Despite suggesting

“bombs the size of pineapples”, the nuclear project is judged not to help war effort

on the necessary timescale and is therefore downgraded in importance.

Responsibility moved from Army Ordnance to Reich Research Council

May/June 1942:

L-IV pile shows

neutron multiplication,

then destroyed in

hydrogen explosion

March 1945:

B-VIII pile at Haigerloch

fails to go critical

Dec 1942:

Chicago pile

critical

Ongoing efforts

at enrichment

May-Dec 1945: Ten

members of team

interned at Farm

Hall, Cambridge

1943: Vemork

heavy water plant

destroyed

4

April 1943: “Los

Alamos Primer”

lecture notes give

complete overview of

bomb project1944/1945: ALSOS

mission to capture

German researchers ,

equipment and dataJuly/Aug 1945:

Trinity, Little Boy and

Fat Man. The Smyth

Report outlines the

Manhattan project

1947:

Heisenberg

publishes his

account in Nature

1968:

The Virus House -

David Irving

1956:

Brighter Than a

Thousand Suns –

Robert Jungk

1947:

ALSOS – Samuel

Goudsmit

(republished 1996)

Arnold Kramish 1985 The Griffin

Mark Walker 1989 German National Socialism and the Quest

for Nuclear Power 1939–1949

UK Government 1992 Farm Hall transcripts declassified

David Cassidy 1992 Uncertainty: The Life and Science of Werner

Heisenberg

Thomas Powers 1993 Heisenberg’s War

Mark Walker 1995 Nazi Science: Myth, Truth, and the German

Atomic Bomb

Paul Lawrence

Rose

1998 Heisenberg and the Nazi Atomic Bomb

Project: A Study in German Culture

Hans Bethe 2000 ‘The German Uranium Project’, Article in

Physics Today

Jeremy Bernstein

and David Cassidy

2001 Hitler's Uranium Club: The Secret

Recordings at Farm Hall


Why were the Allies so worried

about the Germans?For example:

• Heisenberg: Nobel prize 1932 for quantum mechanics and

the ‘Uncertainty Principle’. Refused offer to move to USA

in summer 1939 (when he visited Goudsmit in USA).

• von Weizsäcker: Physicist with extremely good political

connections; pupil of Heisenberg.

• Hahn: Discoverer of fission 1938. Worked with Fritz Haber

on poison gas during WW1. Discovered Protoactinium

1921.

• Clusius: First person (1939) to separate the two naturally-

occurring isotopes of chlorine Cl-35 and Cl-36.

5


6

Einstein’s letter to

President Roosevelt,

2 August 1939

(drafted by Leo Szilard) “I understand that Germany has

actually stopped the sale of uranium

from the Czechoslovakian mines

which she has taken over. That she

should have taken such early action

might perhaps be understood on the

ground that the son of the German

Under-Secretary of State, von

Weizsacker, is attached to the

Kaiser Wilhelm Institute in Berlin,

where some of the American work

on uranium is now being repeated.”


Extracts from the Frisch-Peierls

memorandum, Birmingham UK, March 1940 (written before anyone really knew the scale of the effort needed)

“............it is quite conceivable that Germany is, in fact, developing this

weapon. Whether this is the case is difficult to find out, since the plant for

the separation of isotopes need not be of such a size as to attract attention.

Information that could be helpful in this respect would be data about the

exploitation of the uranium mines under German control (mainly in

Czechoslovakia) and about any recent German purchases of uranium

abroad. It is likely that the plant would be controlled by Dr. K. Clusius

(Professor of Physical Chemistry in Munich University), the inventor of the

best method for separating isotopes, and therefore information as to his

whereabouts and status might also give an important clue.........

“Since the separation of the necessary amount of uranium is, in the most

favourable circumstances, a matter of several months, it would obviously be

too late to start production when such a bomb is known to be in the hands

of Germany, and the matter seems, therefore, very urgent.......

“For the separation of the uranium 235, the method of thermal diffusion,

developed by Clusius and others, seems to be the only one which can cope

with the large amounts required.”7


The view from Soviet Russia

in 1940Georgi Flerov (Soviet physicist who worked on the

Soviet weapons programme and who also discovered in

1940 the spontaneous fission of uranium):

“It seemed to us that if someone could make a nuclear bomb, it

would be neither the Americans, English or French but Germans.

The Germans had brilliant chemistry; they had technology for the

production of metallic uranium; they were involved in experiments on

the centrifugal separation of uranium isotopes. And, finally, the

Germans possessed heavy water and reserves of uranium. Our first

impression was that Germans were capable of making the thing. It

was obvious what the consequences would be if they succeeded.”

8


Some key German scientists

9

Walther Gerlach

1889-1979

Werner

Heisenberg

1901-1976

Otto Hahn

1879-1968

Paul Harteck

1902-1985

Carl-Friedrich

von Weizsäcker

1912-2007

Carl Wirtz

1910-1994Kurt Diebner

1905-1964

Erich Bagge

1912-1996

Walter Bothe

1891-1957

Klaus Clusius

1903-1963


Erich Bagge

1912-1996

Developed a uranium enrichment device in 1944. Nazi Party member.

Prisoner at Farm Hall 1945.

Walther Bothe

1891-1957

Theoretical physicist. Nobel Prize 1954 for study of wave-particle duality. An important member of the German nuclear project, his

measurements led to the conclusion that graphite was not a suitable moderator, probably due to boron contamination.

Klaus Clusius

1903-1963

In 1939 he achieved the separation of the natural chlorine isotopes. During WW2, he worked on isotope separation and heavy water

production. Zurich University 1947 to 1963.

Kurt Diebner

1905-1964

Overall manager of the German nuclear project. After WW2, worked with Bagge on marine applications of nuclear power. Nazi Party member.


Hans Geiger

1882-1945

Developed Geiger counter. Geiger-Marsden experiment (1909) discovered atomic nucleus. Enigmatic, he expressed no views about Nazism.

Walter Gerlach

1889-1979

In 1921 he discovered spin quantisation in a magnetic field (the Stern-Gerlach effect). Head of Physics in the Reichforshungsrat (Reich Research

Council) 1944-1945. University of Munich 1948-1957. Prisoner at Farm Hall 1945.

Otto Hahn

1879-1968

With Lise Meitner, discovered Protoactinium 1921. Director of the Kaiser Wilhelm Institute for Chemistry 1928 to 1946. With his student Fritz

Strassman, and also Lise Meitner and Otto Frisch, he discovered fission in 1938. An opponent of Jewish persecution in Nazi Germany, he did not

contribute to the wartime nuclear research programme. Nobel Prize 1944. Prisoner at Farm Hall 1945.

Paul Harteck

1902-1985

Alerted the Herreswaffenamt (Army Weapons Office) in April 1939 about the possible military applications of nuclear research. Did work on

uranium isotope separation and heavy water production. Developed a prototype centrifuge for isotope separation. Rensselaer Polytechnic

Institute, New York, 1955 to 1968. Prisoner at Farm Hall 1945.

Werner Heisenberg

1901-1976

Key founder of quantum mechanics. Nobel Prize 1932. Technical leader of the German wartime nuclear research programmes. After WW2, he

was involved in the first German nuclear reactor at Karlruhe. Director of the Kaiser Wilhelm Institute for Physics (KWIP) (later re-named the

Max Planck Institute for Physics). Prisoner at Farm Hall 1945.

Pascual Jordan

1902-1980

Theoretical physicist, one of the founders of quantum mechanics. Nazi Party member.

Horst Korsching

1912-1998

A colleague of Karl Wirtz, he worked on isotope separation during WW2. Prisoner at Farm Hall 1945.

Max von Laue

1879-1960

Discovered diffraction of X-rays by crystals. Nobel Prize 1914. A strong anti-Nazi, he took no part in the wartime nuclear research programme.

A prisoner at Farm Hall 1945, this may have been to stop the Soviets capturing him.

Karl Wirtz

1910-1994

Scientist at KWIP who worked on reactor design. University of Gottingen 1948 to 1957. Technische Hochschule Karlsruhe 1957 to 1979.


Carl Friedrich von

Weizsacker

1912-2007

His father was a State Secretary at German Foreign Office from 1938 to 1943. His brother Richard later became President of Germany 1984 to

1994. His grandfather had been Prime Minister of Wurttemburg. He studied under Heisenberg and Niels Bohr. He was involved throughout

WW2 in the German nuclear programme. In 1941 he filed a patent for nuclear bombs. Max Planck Institute for Physics, Gottingen, 1946 to

1957. University of Hamburg 1957 to 1969. Became a Christian pacifist. Prisoner at Farm Hall 1945.

Manfred Ardenne

1907-1997

Early television pioneer. Worked on radar and nuclear research during WW2. Worked on Soviet A-bomb programme after WW2. Worked with

Fritz Houtermans (1903-1966).

Robert Dopel

1895-1992

Experimental nuclear physicist, worked for Heisenberg on design of spherical sub-critical assemblies at Leipzig. Worked on Soviet A-bomb

programme after WW2.

Siegfried Flugge

1912-1997

Theoretical physicist. Worked with Weizsacker. Post-war, he edited the 54 volume Encyclopaedia of Physics.10

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11

Some notable exiles from Nazi mainland Europe


Hans Bethe 1906-2005

Half Jewish German physicist, moved to UK 1933 then USA 1935. Stellar nuclear reaction theory (C-O-N cycle). Head of Theoretical Division in Los Alamos. Bethe-Tait analysis for fast reactor accidents. Nobel prize 1967.

Niels Bohr 1885-1962

Standard model of atom. ‘Copenhagen interpretation’ of quantum mechanics. Half-Jewish. Escaped from Copenhagen in 1943. Nobel prize 1922

Max Born 1882-1970

Joint founder of quantum mechanics. Moved to Britain 1939. Nobel prize 1954.

Enrico Fermi 1901-1954

Italian theoretical physicist (wife Jewish), moved to USA 1938. Led team that built Chicago pile, 1942. Nobel Prize 1938.

Albert Einstein 1879-1955

Moved to USA 1933. Nobel prize 1921.

Otto Frisch 1904-1979

Co-discoverer of fission. Frisch-Peierls memo, March 1940. Nephew of Lise Meitner.

Klaus Fuchs 1911-1988

Non-Jewish Communist party member who fled to UK after Reichstag fire. Los Alamos – design of Fat Man 1944-1945. Harwell head of Theoretical Physics. Russian spy, convicted 1950 – gave Soviets details of bomb design.

Lise Meitner 1878-1968

Co-discoverer of fission, emigrated to Sweden where she stayed throughout WW2.

John von Neumann 1903-1957

Amazing all-round genius. Game theory, computers, Monte Carlo method.

Wolfgang Pauli 1900-1958

Jewish paternal grandparents. Pauli exclusion principle. Moved to US 1940. Nobel prize 1945

Rudolf Peierls 1907-1995

Frisch-Peierls memo, March 1940.Manhattan project. Major role in UK nuclear programme.

Emilio Segre 1905-1989

Jewish Italian physicist, moved to USA 1937. Discovered technetium, astatine and the antiproton. Head of Radioactivity Group, Los Alamos. Nobel prize 1959.

Leo Szilard 1898-1964

Drafted the letter to Roosevelt for Einstein. Another amazing all-round genius. Knew how to make boron-free graphite.

Edward Teller 1908-2003

Technical lead on H-bomb development, alleged basis for ‘Dr Strangelove’. Hungarian Jew who emigrated to USA 1935.

Stanislaw Ulam 1909-1984

Co-inventer with von Neumann of the Monte Carlo method. Helped Teller with the design of the H-bomb.

12

V-1/V-2 vs Manhattan – project comparisonSource: Wikipedia

• Beginning in September 1944, 3,225 V-2s were launched, mostly at London

and later Antwerp and Liège. The attacks resulted in the deaths of an

estimated 9,000 civilians and military personnel, while 12,000 forced

labourers and concentration camp prisoners were killed producing the

weapons – i.e. the V2 killed more in its production than its deployment.

• The German V-weapons (V-1 and V-2) cost $3 billion (wartime dollars)

and were more costly than the Manhattan Project that produced the

atomic bomb ($1.9 billion). 6,048 V-2s were built, at a cost of

approximately 100,000 Reichmarks (GB£2,370,000 (2011)) each.

• SS General Hans Kammler, who as an engineer had constructed several

concentration camps including Auschwitz, had a reputation for brutality and

had originated the idea of using concentration camp prisoners as slave

labourers in the rocket program. (Kammler is believed to have been killed in

May 1945, but this is disputed.)

• CONCLUSION: A Manhattan-scale project would have been possible in

Nazi Germany, if the political will had been behind it.


Scale of German atomic project

vs Manhattan project

• Manhattan project: cost ~ $2 billion (1945)

– Staffing levels ~ 120000 maximum

• German project: cost ~ $2 million(1945)

– Staffing levels ~70 scientists

13


Manhattan project vs German project - overview

14

Process Manhattan project achievements during

WW2

German project

1 Electromagnetic

separation

Oak Ridge, Tennessee, Y-12

‘Calutrons’ up to 84% U-235

No

2 Gas diffusion

separation

Oak Ridge K-25

Used to take enrichment from 2% to 23%

No

3 Thermal diffusion Oak Ridge S-50

Used to enrich up to 2%

Experimental only,

unsuccessful

4 Gas centrifuges –

separation of U-235

Experimental only Experimental only, 1-2% U-

235 achieved early 1945

5 Heavy water

production

Trail, British Columbia (from 1943) Vemork, Norway, from mid-

1930s

6 Uranium-graphite

reactors

Hanford, Washington 250 MWth piles for

plutonium production (also the CP-1 pile in

Chicago and the X-10 pile at Oak Ridge)

No

7 Uranium-heavy water

reactors

CP-3, Argonne, Chicago

(critical 15th May 1944)

B-VIII, Haigerloch, March

1945 (but subcritical)

8 Plutonium separation Hanford ‘canyons’ No

9 Weapon design and

assembly

Los Alamos, New Mexico No


15

2. German project technical

achievements and failures


Organisation (approximate)

16

HeisenbergKWIP Berlin

Theoretical physics

Subcritical assemblies

BotheKWIM Berlin

Nuclear properties

HarteckHamburg

Isotope separation

HahnKWIC Berlin

Nuclear chemistry

DiebnerGottow

Theoretical physics

Subcritical assemblies

Goering/Speer

Schumann (until 1942), Herreswaffenamt HWA

Esau (1942-1944), Reichsforschungsrat RFR

Gerlach (1944-1945), Reichsforschungsrat


ClusiusMunich

Isotope separation

The L-IV pile, Leipzig, 1942

17

The L-IV pile gave the first evidence of neutron multiplication in May 1942.

It was destroyed in a hydrogen explosion in June 1942.


The photo probably shows

the similar-looking B-III pile

which had horizontal layers

of uranium metal and paraffin

wax.

The B-VIII pile, Haigerloch, 1945

18

• Criticality was attempted 24th March 1945.

• Neutron multiplication, “Die maschine geht!”, but no criticality

• No control rods!


19

B-VIII pile, Haigerloch


1500 kg heavy water

>1500 kg U metal cubes

10000 kg graphite

500 mg radium-beryllium

B-VIII museum model

20


“.......the B-VIII reactor was not too far from being a

good working critical reactor.”

Keff = 0.89 approx

B-VIII neutronics analysis, 2009

21


22

ALSOS team recovering uranium metal cubes

buried by the Germans, Haigerloch 1945The ALSOS mission followed the Allied forces into Europe to try to find out whether the

German Bomb project was a real threat. By Dec 1944, they knew there was no real threat.


Uranium cubes from Haigerloch

23


Key mistakes and decisions- 1• “Graphite is unsuitable as a moderator”, (Walther Bothe, 1940)

probably due to boron contamination at the ppm level.

• (In the Manhattan project, Leo Szilard knew that the normal

route for manufacturing graphite involved boron carbide

electrodes. Hence he got the manufacturers to change the

electrode material.)

• Hence the Germans were tied to using heavy water, but

electricity shortages meant this could only be done at the

Vemork hydro plant in Norway.

• The Vemork plant was attacked twice in 1943 by Commandos

and then by Norwegian partisans, which put it out of action for

the rest of the war (as in the film ‘The Heroes of Telemark’)

• RESULT: The Germans never produced enough heavy water to

make an operating reactor (but see Postscript??)24


The Vemork plant and its destruction

25

Vemork Hydroelectric Plant at Rjukan, Norway in

1935. In the front building, the Norsk Hydro

hydrogen production plant, a Norwegian Special

Operations Executive (SOE) team (Operation

Gunnerside) blew up heavy water production cells

on 27 February 1943.This operation effectively

ended heavy water production within the Greater

Reich.

The Germans acquired about 2655kg from Vemork

in total.


Part of the electrolysis plant, now

in the Resistance Museum in Oslo

The importance of the destruction of

the heavy water plant

• “......the elimination of German heavy

water production in Norway was the main

factor in our failure to achieve a self-

sustaining atomic reactor before the war

ended.” Kurt Diebner

26

Key mistakes and decisions - 2

• No serious effort at large-scale enrichment

was made.

• This was because

i. The size of the plant would have been

prohibitive (huge power consumption, it

would have been a target for bombing, huge

effort would have been needed)

ii. Heisenberg over-estimated the necessary

amount of U-235 for a bomb

27


Enrichment:

lab-scale efforts

28

The Clusius-Dickel tube had worked for

chlorine isotope separation, but it

could not be made to work effectively

with uranium hexafluoride.


Enrichment:

Experimental

centrifuge

29

Early 1945: Centrifuges were

finally in operation at Celle, 2.5

hours by train from Hamburg.

By late Spring 1945, they were

producing 50 gms per day of

uranium with “15 percent more

U235 than normal”.


Enrichment - outcome

“In comparing the progress with the

centrifugal method of separation made by

the Germans and by ourselves it is clear

that at the end of the war they were far

behind where we were in this country at

the end of 1943…………”

From US report, 1946

30


Key mistakes and decisions - 3• There was a belief that the nuclear project could

not yield any benefit to the war effort before the

war was over.

• This was correct in hindsight – even the

Manhattan project did not deliver until after the

European war was over.

• In 1941, when the Germans might have begun a

major effort on nuclear weapons, the war

seemed already won.

• By 1943/44, the Allied bombing made any major

effort very difficult.31


Allied bombing

• In 1943/44, the laboratories in Hamburg,

Leipzig and Berlin all suffered severe

disruption because of bombing.

• Developments slowed. In 1944, the nearly-

completed B-VII reactor was disassembled

and moved to Haigerloch (where it

became B-VIII).

32


33

3. Political and organisational

factors


Deutsche Physik vs

Jűdische Physik• Phillipp Lenard and Johannes Stark were old Nobel-

winning classical physicists who had been left behind by

relativity and quantum physics.

• They were both early Nazi party members.

• In the 1930s, they used their positions to criticise modern

physics as ‘Jewish’ and ‘non-Aryan’.

• Heisenberg was described (1934) as a ‘white Jew’.

• Heisenberg appealed to Himmler who eventually (1937)

supported him. This issue was then put to rest – but

there were possibly lingering doubts.

34


The ‘Coming-out Party’, Feb 1942

(and further meeting with Speer/Milch in

June 1942)

35

1. Nuclear physics as a weapon

2. The fission of uranium nuclei

3. The theoretical basis for energy production from uranium fission

4. Results of experimental arrangements so far on energy production

5. The need for further basic research

6. Enrichment of uranium

7. Production of heavy water

8. The expansion of the nuclear physics project

Heisenberg, “A bomb the size of a pineapple

could destroy a city.........”

Geheim = Secret

A seminar to present the results of basic research

to political and military leaders


Loss of focus• Heisenberg published a book about cosmic rays in 1943.

Others were doing non-project-related work also.

• Heisenberg and others spent a lot of time in 1943/44

acting as ‘cultural ambassadors’, giving lectures within

Europe.

• Heisenberg visited Holland, Switzerland,

Czechoslovakia, and Poland.

• Heisenberg visited Poland at the invitation of Hans

Frank, Governor General, who was an old school friend.

• (Frank was executed at Nuremberg. ‘‘What we recognize in Poland

to be the elite must be liquidated.’’ Poland, he said, was to ‘‘become a society of

peasants and workers’’ with no ‘‘cultured class.’’ As far as Poles were concerned,

higher education as well as Polish theatre and literature was to cease. The language

itself was to be obliterated. Heisenberg in Poland, J Bernstein, Am J Phys, 72 (3)

2004)

36


37


The ‘Railway Switchyard’

38

4. Motives, ethics,

competence and honesty


Why did the project fail? - 1

The Jungk/von Weizsäcker/

Heisenberg/Powers version:

I. “We only wanted to make a uranmaschine.”

II. We procrastinated to ensure Hitler didn’t get

the bomb (German scientists as heroes)

III. But....we could have made a bomb if we had

wanted to (i.e. We didn’t screw up)

IV. And.... we lacked the moral courage to

recommend a project requiring 120000

people.39


The Jungk/von Weizsäcker/

Heisenberg/Powers versionRobert Jungk, Brighter than a Thousand Suns, (Heller

als Tausend Sonnen), 1956:

“It seems paradoxical that German nuclear physicists, living under a

sabre-rattling dictatorship, obeyed the voice of conscience and

attempted to prevent the construction of atomic bombs, while their

professional colleagues in the democracies, who had no fear, with

very few exceptions concentrated their whole energies on the

production of the new weapon.”

Arnold Kramish, The Griffin, 1986:

“Jungk’s book was an early example of the shameful fiction that has

now been taken as gospel.”

40


Jungk recants (1990)

“That I have contributed to the spreading

of the myth of passive resistance by the

most important Nazi physicists is due

above all to my esteem for these

impressive personalities, which I have

since realised to be out of place.”

41


Heisenberg’s visit to Bohr in

Copenhagen, September 1941(Michael Frayn’s play ‘Copenhagen’)

• Bohr’s version: Heisenberg told him that (a) Germany had won, (b)

Germany was developing nuclear weapons, (c) Did Bohr want to

help?

• Heisenberg’s version: (a) He feared the Allies were developing

nuclear weapons, (b) He wanted to spare Germany the

consequences, (c) He wanted Bohr to get a message to the Allies to

say that Germany was nowhere near producing nuclear weapons.

• We will never really know what passed between them.

• They knew each other very well. Each spoke the other’s language

well.

• Either (i) one of them lied, or (ii) they just misunderstood each other.

• Did Bohr have any motive to tell a lie?

42


Letter from Lise Meitner to

Max von Laue, June 1945

“One should force a man like Heisenberg

and many millions like him to go to these

camps and see the martyred victims. His

visit to Denmark in 1941 is unforgivable.”

(quoted in Kramish)

43


Copenhagen –

Recent developments• Unsent draft letters from Bohr to Heisenberg dated 1958 were

published in 2002, which showed that Bohr remained extremely

annoyed with Heisenberg for allowing Jungk (“Brighter than a

Thousand Suns”) to repeat Heisenberg’s version of the Copenhagen

meeting and to re-state the ‘Heisenberg version’ of German

innocence.

“I carefully fixed in my mind every word that was uttered. It had to make a very

strong impression on me that at the very outset you stated that you felt certain

that the war, if it lasted sufficiently long, would be decided by atomic weapons. At

that time I had no knowledge at all of the preparations under way in England and

America, and when I did not reply and perhaps looked doubtful, you told me that I

had to understand that in recent years you had occupied yourself almost

exclusively with this question and were certain that it could be done. On the

other hand, there was no hint on your part that efforts were being made by

German physicists to prevent such an application of atomic science........my

alarm was not lessened by hearing from the others at the Institute that

Weizsacker had stated how fortunate it would be for the position of science in

Germany after the victory that you could help significantly towards this end.”

44


Von Weizsacker bomb patent

• A draft patent by Carl-Friedrich von Weizsacker for a

plutonium bomb, dated 1941, has recently been found in

Russian archives.

• This further undermines the Jungk/Heisenberg/von

Weizsacker/Powers idea that the German team were

never interested in developing weapons.

45



The Goudsmit/Rose version:

I. They were incompetent.

II. They didn’t know how to make a bomb.

III. They couldn’t even calculate the critical

mass of a bomb.

IV. They thought they could build a reactor

without control rods.

V. They were a bunch of amateurs: it was a

one-man band where they were all in awe of

Heisenberg, who was a prima donna.46


How competent were the

German team?Did they really understand:

• The difference between a reactor and a

bomb?

• Delayed neutrons?

• The need for control rods?

• An accurate value for the critical mass for

a bomb?

47


Samuel Goudsmit, ALSOS,

1947

“The plain fact of the matter is that the

Germans were nowhere near getting the

secret of the atom bomb. Indeed, at the

rate they were going and the direction they

were taking, it is anybody’s guess if they

would have arrived at it at all in any

practicable period of time.”

48



The Hans Bethe version (1990):“The explanation is that the Germans rejected the

separation of uranium isotopes as too difficult. They saw

the fissionability of plutonium as the key to the entire

project. Once you had a chain reaction you could make

plutonium, and once you had plutonium, you could make

a bomb. However, if they had achieved the reactor, they

would have found that the road from there to a bomb

was still full of obstacles.”

However, the plutonium route was stymied by lack of

heavy water......49


The truth:

The Farm Hall transcripts,

not published until 1992

• Ten of the German physicists were interned in

Cambridgeshire from May 1945.

• They didn’t known anything at all of the Manhattan

project.

• They still thought they were world leaders in nuclear

research, and that they could do a deal with the Allies.

• The Hiroshima bombing was announced on the BBC

news at 9pm on 6th August.

• They didn’t realise the building and its grounds were

bugged:-

50


Some key German scientists at

Farm Hall (8 of the 10)

51

Werner

Heisenberg

1901-1976

Otto Hahn

1879-1968

Paul Harteck

1902-1985

Walter Gerlach

1889-1979

Carl-Friedrich

von Weizsäcker

1912-2007

Carl Wirtz

1910-1994

Kurt Diebner

1905-1964

Erich Bagge

1912-1996


Farm Hall, 6th August 1945,

dinner conversation, 9pm till late:HAHN: “If the Americans have a uranium bomb then you’re all second raters. Poor old Heisenberg.”....

HEISENBERG: “All I can suggest is that some dilettante in America who knows very little about it has

bluffed them......I don’t believe a word of the whole thing.”....

von WEIZSACKER: “I don’t think it has anything to do with uranium.”.....

GERLACH: “They’ve got (plutonium) and have been separating it for two years.”....

HEISENBERG: “I consider it perfectly possible that they have about ten tonnes of enriched uranium,

but not that they can have ten tonnes of pure U-235.” (!!!??? Heisenberg doesn’t know the

critical mass!!!!).....

HAHN: “But tell me why you used to tell me that one needed 50kg of 235......now you say you need

two tonnes?”.....

HARTECK: “You could do it with 100,000 mass spectrographs”.....

von WEISZACKER: “I believe the reason we didn’t do it was because all the physicists didn’t want to

do it, on principle. If we had all wanted Germany to win the war we could have succeeded.”

HAHN: “I don’t believe that.”

von WEIZSACKER (after Hahn has left room): “If we had started this business soon enough we could

have got somewhere.”......

WIRTZ: “It is characteristic that the Germans made the discovery and didn’t use it, whereas the

Americans have used it.”......

GERLACH: “When we get back to Germany we will have a dreadful time. We will be looked on as the

ones who have sabotaged everything. We won’t remain alive long there.........Isn’t it a pity that the

others have done it?

HAHN: “I am delighted.” 52


Farm Hall, 6th August 1945,

later that evening:

• Heisenberg to Hahn: “One neutron always makes two

others in pure 235. That is to say, in order to make 1024

neutrons I need 80 reactions, one after the other.

Therefore I need 80 collisions and the mean free path is

about 6 cm. In order to make 80 collisions, I must have a

lump of a radius of about 54 centimetres and that would

be about a tonne.”

• WRONG!!

53


Extract from the Frisch-Peierls memorandum, Birmingham, UK, March 1940

54

U-235 bomb

Pu-239 bomb

Extract from “The Los Alamos Primer” lecture notes, Robert Serber, April 1943


Conclusions from Farm Hall

• There are parts of this story – particularly about

motives and ethics – that will never be fully

understood.

• It seems that von Weizsäcker and Heisenberg

didn’t want to go down in history as either

scientific failures, or as closet Nazis. Instead,

they tried to write their own history as saints.

• This was a lie, and they were eventually found

out.

55


1. Until mid-1942, the German team was (arguably) in the lead. However,

until 1942, the Germans thought the war would be over too soon for

nuclear research to have any effect. After 1942, the bombing of Germany

would have made any major new project very difficult.

2. If their priority had been the Bomb instead of the V weapons, things might

have been different..............

3. The failure to use graphite as a moderator, and the destruction of the

Vemork plant, were undoubtedly significant.

4. The German scientists seemed reluctant to push for a big project because

they were uncertain of delivery. Arguably, no big project would have been

sanctioned anyway until an operating reactor had first been demonstrated.

5. They didn’t pursue cyclotrons, or gas diffusion, for uranium enrichment.

6. Any claims that German scientists deliberately delayed developments, as

part of passive resistance to the Nazi regime, now seem discredited.

56

So why didn’t Hitler get the Bomb?

There is no single answer........


57

Conclusion?Heisenberg, Harteck and Diebner might have been able to make an atomic

bomb for Hitler in the time available. However:– The ‘time available’ was much longer than was realised in 1940.

– They will have been concerned about the possibility, and the consequences, of failure if they

talked up the Bomb.

– There was no panic about ‘the other side getting there first’, because they thought they were

first. Also, they were in a protected project which meant they were not likely to be conscripted.

“With the beginning of the war there arose of course for every German

physicist the dreadful dilemma that each of his actions meant either a victory

for Hitler or a defeat of Germany, and of course both alternatives presented

themselves to us as appalling. Actually, I suppose that a similar dilemma

must have existed for the physicists active on the allies' side as well, for once

they were signed on during the war, they also were signed on for Stalin's

victory and Russia's foray into Europe. Overall, the German physicists acted

in this dilemma as conservators of sort of that which was worthy and in need

of conserving, and to wait out the end of the catastrophe if one was lucky

enough to still be around.”

Heisenberg letter to Robert Jungk, 1956 from http://werner-heisenberg.unh.edu/


http://werner-heisenberg.unh.edu/

Downloads:

1. The Frisch-Peierls memorandum from March 1940: An unbelievably brilliant piece of work by two

German Jewish exiles working alone in blacked-out Birmingham in the first winter of the war. This report

started the MAUD committee and the ‘Tube Alloys’ work in the UK. They were working for Mark Oliphant,

who in 1941 went to the USA and persuaded the Americans to get serious about the Bomb.

2. “The Los Alamos Primer”, Robert Serber’s lecture notes from April 1943 for people who were new to the

Manhattan project: This lays out the full scope of the project more than two years before it reached fruition.

Books:

1. Jeremy Bernstein: Hitler’s Uranium Club: the Secret Recordings at Farm Hall (2nd Ed, 2001) gives the

actual words spoken as they heard about the Manhattan project.

2. Mark Walker: German National Socialism and the Quest for Nuclear Power 1939-1949 (1989) is a

detailed history. (It was actually Walker’s PhD thesis at Princeton).

3. Samuel Goudsmit, ALSOS (1947, republished 1996) is a good light read, and it captures the raw emotions

and paranoia of 1945. (Goudsmit’s parents had died at Auschwitz and some of his judgment seems clouded

as a result.)

4. David Cassidy: Uncertainty, The Life and Science of Werner Heisenberg (1992)

5. David Irving: The Virus House (1968, out of print) gives a very good technical account.

6. Paul Lawrence Rose: Heisenberg and the Nazi Atomic Bomb Project (1998) is an outspoken critique of

Heisenberg and Powers.

7. Arnold Kramish: The Griffin (1986) gives a fascinating account of the life of Paul Rosbaud, editor of the

journal Naturwissenschaften, and a British spy.

8. Thomas Powers: Heisenberg’s War (1993) which continues the Heisenberg myth.

9. Rainer Karlsch: La Bombe de Hitler (2005, tr. into French 2007), a slightly hysterical and unlikely ‘history’

focussing on Diebner’s alleged activities in Gottow in 1944/45.58

Recommended reading


Recommended viewing1. Copenhagen, stage play by Michael Frayn (1998) (available as

BBC play on YouTube, with Daniel Craig) VERY GOOD – but too

sympathetic to Heisenberg?

2. The Heroes of Telemark, directed by Antony Mann, starring Kirk

Douglas and Richard Harris (1965) AWFUL - action thriller, low on

context

3. BBC Horizon Hitler’s Bomb (1992) – contains fascinating interviews

with von Weizsacker and Bagge, which make the programme too

biased and sympathetic to the ‘Heisenberg version’

http://www.youtube.com/watch?v=eV-ElwRwdlM

Also: A play "Operation Epsilon" by Alan Brody, largely based on the Farm Hall transcripts, opened on

March 7, 2013 in Cambridge, Massachusetts. A staged reading of the play "Farm Hall" by David

C. Cassidy, was presented on February 15, 2013 in the Science & the Arts program at The

Graduate Center of the City University of New York. A second reading was performed on March

20, 2013 at the annual March meeting of The American Physical Society in Baltimore, Maryland.

59


http://www.youtube.com/watch?v=eV-ElwRwdlM

60

Postscript:

The lunatic fringes


Rainer Karlsch “Hitlers Bombe”

61

Rainer Karlsch, “Hitlers Bombe” (2005) (also “La Bombe de Hitler”, 2007):-

“The G-IV reactor went critical in Gottow in late1944”. He says that radiation

measurements have proved this, while others say it is just traces of fall-out from

Cold War weapons tests or Chernobyl.

My view: He is on the lunatic fringe......BUT he did get Mark Walker to be his co-author in a

paper summarising his ‘findings’ in Physics World, June 2005, “New light on Hitler’s Bomb”

Gottow c 2010. It was evacuated on 26th April 1945. The Red Army dismantled

the site and some personnel continued work in the USSR.


Photos show the G-III pile in Gottow in 1943

http://www.deutsches-museum.de/archiv/archiv-

online/geheimdokumente/forschungszentren/gottow/diebner-gottower-versuch-g-

iii/dokument-4/

See also:

• Erster Atomreaktor der

Welt oder die

Uranmaschine

http://www.youtube.com/

watch?v=0DKD99zMp4A

Diebner seems to have

done a good job of

destroying paperwork at

the end of the war. Hence

activities at Gottow

remain less clear than

elsewhere. There are no

known photos or

diagrams of the G-IV pile.

62


http://www.deutsches-museum.de/archiv/archiv-online/geheimdokumente/forschungszentren/gottow/diebner-gottower-versuch-g-iii/dokument-4/

http://www.youtube.com/watch?v=0DKD99zMp4A

Rainer Karlsch - 2

• Rainer Karlsch also claims that two ‘weapon’ tests were carried out

in Ruegen (in the Baltic) in October 1944 and Ohrdruf (Thuringia) in

March 1945, under Kurt Diebner’s control.

• Karlsch claims that the tests involved attempted fusion devices,

using conventional explosives and deuterium. His evidence for this

is flimsy to say the least.

• He goes on to claim that one of the tests killed 500 prisoners of war,

which sounds highly unlikely.

• However, Irving (1968) also said that crude efforts at fusion were

attempted.

• Also, in 1957 Diebner took out a patent for a ‘fusion device’ using

implosion with conventional explosives and electric arcing.

• So-called ‘fourth generation’ or pure fusion bombs (using

chemical explosives to trigger fusion) have apparently never been

produced to date.....

63


Rainer

Karlsch

- 3

• Rainer Karlsch also

found a German drawing

of a bomb, dated c

1945/1946 of unknown

source.

• It is definitely post-war –

so it proves nothing.....

• Also, it shows a gun-

style plutonium bomb –

which wouldn’t work.......

64


The Daily Mail.......

Daily Mail, 13th July 2011

Nazi nuclear waste from Hitler's secret

A-bomb programme found in mine“126000 barrels of waste found 2000 feet down in old salt mine near

Hamburg.”

This sounds extremely unlikely! Mark Walker is quoted as saying 'Because we still

don’t know about these projects, which remain cloaked in WW2 secrecy, it isn’t safe

to say the Nazis fell short of enriching enough uranium for a bomb. Some documents

remain top secret to this day. Claims that a nuclear weapon was tested at Ruegen in

October 1944 and again at Ohrdruf in March 1945 leave open a question, did they or

didn’t they?'

65


“Soviets got U from Berlin”

• “The Soviets got 300 tonnes of natural uranium from the

Auer factory in Berlin at the end of the war.” It is claimed

this helped to kick-start their bomb programme.

• This seems plausible to me.

66


Post-war legacy67

SS Otto Hahn – nuclear powered cargo

ship, operated 1968-1979.

Atucha 2 PHWR, Argentina:

A unique design with U-nat

fuel , pressure vessel design,

on-load refuelling.


68

Thank you!


Extra material

69

71

Heavy water was first isolated in 1931. (E. W. Washburn and H. C. Urey, Proc. Nat. Acad. Sci. 18 (1932) 496) Harold Urey won the Nobel

Prize in 1934. (Urey worked on uranium enrichment using gaseous diffusion during WW2 although Little Boy

(Hiroshima) used U-235 produced using electromagnetic separation (‘Calutrons’)).

It is necessary to electrolyse 2700 litres of natural water to obtain one litre of water enriched in deuterium by

10%; this requires 320 MW-hours of electrical energy. By repeating the process of electrolysis, pure heavy

water can be produced; this is a conceptually simple method but it is very expensive.

Small amounts (grams) for scientific use were available in the United States by 1933.

Yes, you can drink it.

Jomar Brun, the Head of Hydrogen Research at Norsk Hydro, and Leif Tronstad, a physicist from Trondheim,

realized that the conditions for large-scale production (kg) of heavy water existed at Norsk Hydro’s plant in

Rjukan, where large amounts of water were already being electrolyzed as part of the Haber-Bosch process

for producing ammonia for nitrogen fertilizer.

They drew up a plan, with some involvement from Karl-Friedrich Bonhoffer, a German physical chemist at

Leipzig (and brother of Dietrich, the anti-Nazi theologian who was hanged by the Nazis in April 1945), for the

industrial production of heavy water. It was an impressive venture as a large amount of equipment had to be

built – hundreds of combined electrolysis, combustion and condensation cells - and the market must have

been uncertain. However, Norsk Hydro went ahead, and built a plant by the generator building at Vemork.

First production of 99% pure D2O was in January 1935.

In 1937, Hans von Halban and Otto Frisch (again!!), working at Bohr’s Copenhagen laboratory, noticed that

heavy water had very low neutron absorption compared to light water.

Pre-WW2 history of heavy water, and other trivia


The practicality of fourth

generation (pure fusion) bombsfrom The Question of Pure Fusion Explosions Under the CBTB,

SL Jones and FN von Hippel, Science and Global Security, 1998, 7, pp 129-150

“The advent of the CTBT has probably also renewed interest at the weapons labs in attempting to

ignite DT fusion directly using high-explosive implosion systems, if only because this will be

one of the remaining experimental challenges that the designers of nuclear weapon implosion

systems can use to hone their skills. Although US progress in this area is classified, in early1992

the Russian weapon laboratories reported neutron yields of 1013 -1014 neutrons, corresponding to

the fusion of 10-10 to 10-9 grams of DT gas. The production of 1014 neutrons would be

accompanied by the release of an amount of fusion energy equivalent to roughly 60 mg of

TNT. The associated radiation dose at one meter would be about 0.2 Gy (20 rads) - significant but

not great enough to cause death in the short term.

“Hans Bethe, who headed of the Los Alamos Theory Division during World War II, has expressed

skepticism that such activities might lead to pure fusion weapons. However, he wrote a letter to

President Clinton in April 1997 stating that "the time has come for our Nation to declare

that it is not working, in any way, to develop further weapons of mass destruction of any

kind. In particular, this means not financing work looking toward the possibility of new

designs for nuclear weapons such as pure fusion weapons." If such a policy were

announced, there would need to be more specific guidance with regard to permissible activities.

The purpose of this paper is to begin laying a technical basis for such guidance.”

72


Gottow

• Experimental Station Gottow the Research Department of the Army Weapons Office (HWA). This division

is divided into five sections, which are in turn subdivided into units, were, as the Unit I nuclear physics,

physics and unit Ib explosive shaped charges, etc. experiment was mainly due to new weapons

developments such as rocket motors, grenade launchers, rifles remain in the field of electronics, sound

and acoustics, and various chemicals.

The most famous experiments and developments test site were first developed under high involvement

Wolfram Eschenbach N-material, an aggressive inorganic fluorine compound, which self-fire resistant

materials are burned and built for a short time later a separate large underground plant Falkenhagen was.

Secondly, the experiments Kurt thief agent in the development of a "uranium machine" to name in 3 trials

(the trials GI to G III), he tried his team to a running nuclear reactor using a neutron source and cubes of

natural uranium build. On 20/04/1945, the Army Research Office was Kummersdorf Gottow including the

test site to evacuate. The test site Gottow by the Red Army, all existing facilities and equipment

dismantled and confiscated. Some employees were asked for their scientific work in the Soviet Union to

continue.

In 1955/56, the area was transformed into an arms depot and expanded.

73

Enrichment – differences

between German and UK/US

approaches

• No attempt was made at large-scale electromagnetic

separation (c.f. The Y-12 plant at Oak Ridge, which used

‘Calutrons’ – large cyclotrons – and produced the U235

for Little Boy).

• No attempt was made at developing gas diffusion

technology (c.f. The K-25 plant at Oak Ridge, and also

Capenhurst in Cheshire for the UK nuclear programme

after WW2.)

74


nazi nuclear research - safety in engineering

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