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The Manhattan Project, 1942-44Building an Atomic Infrastructure

• “The Manhattan Project bore no relation to the industrial or social life of our country; it was a separate state with…its thousands of secrets. It had a peculiar sovereignty, one that could bring about the end, peacefully or violently, of all other sovereignties.” – Herbert S. Marks

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Manhattan Project

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Manhattan Project Scientists:Soldiers out of Uniform

• Their participation in Manhattan Project –The single most profound experience in the history of the American scientific community.

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Back in the U.S…• Vannevar Bush and the National Defense Research

Council (NRDC) take over US uranium work. James Conant (chemist and pres. of Harvard put in charge)

E. Lawrence

Arthur ComptonV. Bush

J. Conant

Karl Compton

A. Loomis

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• 1940-41: Money begins to flow– July 1940 - $40,000 more put into work

• Efforts directed not for bomb but for EnricoFermi’s studies of uranium reactor.

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• By fall of 1941, Compton, Conant, Lawrence, Bush – encouraged by MAUD report – urge FDR to undertake large bomb project.

• FDR separates scientists from policy decisions.

• FDR (informally) authorizes $1.2 million and urges crash program.

• December 6, 1941: FDR authorizes the Manhattan Engineering District.

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Manhattan Project Expands

• After Pearl Harbor, FDR OK’s some $1.2 million to be spent.

• American bomb effort re-named the Manhattan Project

• Put under U.S. Army control in 1942.– Why the Army?

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Questions for the Manhattan Project and a mission

• Is a chain reaction possible in practice?• How to produce bomb-grade uranium and

plutonium?• A successful bomb project – needs

industrial-scale resources, superior management, and the will to succeed.

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The Met Lab

• The Metallurgical Laboratory at the University of Chicago founded early 1942– Run by Nobel laureate Arthur Compton– Fermi moves from Columbia to Chicago

• Some of the Met Lab’s goals: – Prove that a chain reaction is possible– Develop ways to extract Pu from U

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Fermi and Chicago Pile-1

• Early studies encouraging – probably less U-235 needed to get a critical mass

• Enrico Fermi leader of group studying chain reaction.

• Fermi scales up reactor studies.• By December, 1942 – Fermi & Co. build a

test atomic “pile”

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Stagg Field, Chicago

Enrico Fermi, 1942

One of the graphite-uranium layers in CP-1

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CP-1

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The New World• James Conant receives

coded message from Compton: – “The Italian navigator

has landed in the New World.”

• First controlled nuclear reaction.

• Produced miniscule half a watt of energy.

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Fermi

Szilard

Szilard to Fermi: “This will go down as a black day in the historyof mankind…”

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Two weeks after CP-1 debuts…

• FDR approves another $250 million (about $3 billion today) to scale up to production.

• American expertise in industrial production to make U-235 and Pu-239.– This is an area where America excels.

• The Manhattan Project is now less of a scientific endeavor than massive engineering effort.

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Building an Atomic Infrastructure

• Niels Bohr (1939): Building an atomic bomb “can never be done unless you turn the United States into one huge factory.”

• This becomes the means to the end.

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Managing the Manhattan Project

• Manhattan Project requires a master organizer. This is Brig. Gen. Leslie Groves.

• Groves placed in charge of the Manhattan Project in September 1942.

• Who is Leslie Groves?

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Gen. Leslie R. Groves… “the angriest officer in the Army.”

• b. 1896 – d.1970• College education; Army Corps

of Engineers; in charge of building the Pentagon.

• His assignment – “Draw up plans for the organization, construction, operation and security of the project, and after approval, take the necessary steps to put it into effect.”

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Groves’ Challenges

• Choose industrial sites for uranium and plutonium production

• Select industrial contractors

• Keep schedule• Maintain security• Nurture relationship with

scientists– Groves and J. Robert

Oppenheimer

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Groves’ Genius

• Ability to grasp essentials• Willingness to take risks• Ability to amass and apply resources• Manage the tension between scientists and

military• Maintain project security

– Compartmentalization, deception (see JRO letter to LG)

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Building an Atomic Infrastructure

• Groves given incredible latitude and resources to complete his tasks

• One of the first major tasks – get industrial scale production of uranium and plutonium started

• Which to pursue – a uranium or plutonium bomb? – Groves: “Both.”

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Building an Atomic Infrastructure• Groves picks 3 major sites

for building the atomic bomb– Oak Ridge, TN – uranium

processing– Hanford, WA – plutonium

production– Los Alamos, NM – scientific

research, design, construction, and testing (operated by Univ. of Calif.)

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Building an Atomic InfrastructureOak Ridge, TN

• Located near Knoxville, TN; sprawling complex on 59,000 rural acres that Groves bought

• Groves’ “troops” erect small city of hundred of buildings employing some 22,000 men and women with its own power plant.

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Early View of Oak Ridge

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Gaseous diffusion plant; Oak Ridge$500M; 12,000 workers

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Producing U-235 at Oak Ridge• Two methods pursued in tandem: gaseous

diffusion and electromagnetic separation.• As Groves said, “If there is a choice

between two methods, one of which is good and the other looks promising, then build both.”

• Both methods based on different size/weight of U-235 vs. U-238. Goal was a few ounces of U-235 a day.

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1. Gaseous diffusion done first– Plant (codename K-25) built at cost of $10.7

billion [2003 dollars]

2. This was then fed into a second stage which enriched it further

3. Electromagnetic separation (a variation of what a cyclotron does)– Plant code-named Y-12 built for $10 billion

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Electromagnetic Separation

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“Calutron” Operators at Oak Ridge

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“Racetrack” for Separating U-235

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What they want…

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Building an Atomic InfrastructureHanford, WA

• Located in desert valley of Washington near Columbia River– River was key for cooling reactors and providing power

• Hanford became a sprawling atomic boomtown –Built and operated by DuPont Chemical Corporation for $1.

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Life at Hanford• A story of superlatives – Hanford becomes

fourth largest city in WA while reactors are built.– Largest general delivery post office in the

world– Work week – 54 hours over 6 days– Meals – 50 tons a day – were 69 cents for all

you could eat. • Science vs. engineering at Hanford

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Building an Atomic InfrastructureHanford, WA

One of three reactor plants built at Hanford

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T Plant, Chemical Separation Building, Hanford, Washington

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Building an Atomic InfrastructureHanford, WA

• Plutonium “bred”at Hanford– U-238 bombarded with neutrons– Gradually decays to form Pu-239 (with some

Pu-240 as impurity)• By 1944, Hanford reactors are producing

some 250 megawatts of power (vs. half a watt two years earlier in Chicago)

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Building an Atomic Infrastructure

• By the end of 1944: both uranium and plutonium suitable for bombs are being produced at industrial-scale facilities.

• The bigger picture…by end of 1944, Germany appears almost defeated…Question: Why continue with Manhattan Project?– Note: Japanese fleet considered a possible

target as early as 1943.

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Building an Atomic Infrastructure

• The bigger picture: Investing several hundred million dollars into massive factories producing large amounts of uranium and plutonium indicated one key thing:

• The US was permanently committing itself to atomic weapons.

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War Developments• Firebombing of Hamburg

(July 1943); 45,000 civilians killed.– Stated goal: “To destroy

Hamburg”– Why? “shortening and winning

the war.”• One atrocity in escalating

war of atrocities – Bataan, concentration camps, Soviet front.

• Dresden, Berlin, Tokyo, etc. all firebombed.

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Meanwhile, on a desert mesa in New Mexico…