The Manhattan Project

SECTION 1 – Is it Possible?

1939

The first contact with the government happened in 16 March 1939. At the urging of Leo Szilard and Enrico Fermi,  George Braxton Pegram, dean of Columbia University, wrote to Admiral S. C. Hooper, then director of the technical division of naval operations.^7.3 Pegram contacted the Navy Department and arranged for a conference between representatives of the Navy Department and Enrico Fermi.^13.1 Fermi suggested the idea of using slow-neutrons for achieving a controllable reaction and fast-neutrons for explosive reactions to representatives of the Navy department. He pointed out, however, that the data available at the time was still insufficient for accurate predictions.^23.1 The only outcome of this conference was that the Navy expressed interest and asked to be kept informed. The next attempt to interest the government was made by Leo Szilard and Eugene Wigner.^13.1

In the spring of 1939, after the experimental confirmation of fission taking place in January there was an almost immediate interest in the possible military use of the large amounts of energy released. In an effort to stop the publication of scientific papers centered around atomic fission, a small group of foreign-born physicists centering on Szilard, and including Wigner, Edward Teller, V. F. Weisskopf, and Fermi began advocating to this end. This group enlisted the help of Niels Bohr‘s cooperation in an attempt to stop publication of further information by voluntary agreement of scientists, both American and foreign. Leading American and British physicists agreed, but F. Joliot, France’s foremost nuclear physicist, refused, apparently because of the publication of one letter in the Physical Review sent in before all Americans had been brought into the agreement. Consequently publication continued freely for about another year although a few papers were withheld voluntarily by their authors.^23.2

Leo Szilard, Eugene Wigner, and Edward Teller asked Albert Einstein, to call nuclear energy to the attention of the President, believing that German scientists were more likely to build a bomb from the discovery of fission, than see this as a source of energy.^14.1

After discussing the Szilard and Einstein letter with Alexander Sachs on October 11, 1939, President Roosevelt had his military aide, Brigadier General Edwin M. Watson create a committee with the power to take what action was appropriate.^7.2 The result of this order was the Advisory Committee on Uranium, which consisted of Lyman J. Briggs of the National Bureau of Standards as chairman, Colonel Keith F. Adamson of the Army Ordnance Department, and Commander Gilbert C. Hoover of the Navy Bureau of Ordnance.^1.2 This was the only committee on uranium that had official status up to the time of organization of the National Defense Research Committee (NDRC) in June 1940.^13.1 The committee met very informally and included various additional scientific representatives in its meetings.^23.4

Advisory Committee on Uranium (Uranium Committee)

Lyman J. Briggs (Chairman) Colonel K. F. Adamson (Army) Commander G. C. Hoover (Navy)

The First Report

The first meeting of the Advisory Committee on Uranium (Uranium Committee) was on October 21st 1939^14.1, Lyman J. Briggs called for it to be held at the Bureau of Standards with the basis of discussion surrounding a memorandum prepared by Szilard.^23.4 Joining the committee were two Washington physicists–Fred L. Mohler of the Bureau of Standards and Richard B. Roberts of the Carnegie Institution–and three physicists of Hungarian origin–Leo Szilard, Eugene Wigner, and Edward Teller. The latter three were invited at Sach’s initiative and the focus of the meeting was on the opinion of it being impossible to attain a chain reaction in a system composed of uranium oxide or metal and carbon in the form of graphite. Sachs also arranged for Einstein to be invited, however, his invitation was not accepted.

As a result of this first meeting, on November 1st, the Advisory Committee on Uranium via Lyman J. Briggs, Colonel Keith F. Adamson, and Gilbert C. hoover^23.4, submitted a report which detailed to the president that a chain reaction was possible but that it was still unproved. If it could be achieved it might supply power for submarines. If the reaction should be explosive, “it would provide a possible source of bombs with a destructiveness vastly greater than anything now known.” The Uranium Committee believed that despite the uncertainties, the Government should support a thorough investigation. It urged the purchase of four tons of pure graphite at once and the acquisition of fifty tons of uranium oxide in the event that the preliminary investigations justified continuing the program.

1940

Shortly after the, November 1st, report was published the first funds were transferred from the Army and Navy in the amount of $6,000 by memorandum from Briggs to General E. M. Watson^23.5  dated 20 February 1940 for the purchase of materials recommended by the committee.^1.3 Briggs and his colleagues advocated including Karl Taylor Compton, Albert Einstein, George B. Pegram, and Alexander Sachs into the Uranium Committee^12.1

The next meeting of the Advisory Committee on uranium was on April 28th, 1940 and was attended by Sachs, Wigner, Pegram, Fermi, Szilard, Briggs, Admiral H. G. Bowen, Colonel Adamson, and Commander hoover. By the time of this meeting, two important factors had come to light. First, it had been discovered that the uranium fission caused by neutrons of thermal velocities occurred in the U235 isotope only. Second, it had been reported that a large section of the Kaiser Wilhelm Institute in Berlin had been set aside for research on uranium. No recommendations emerged from this meeting other than the general consensus that work should be pushed more vigorously.^23.5

A letter from Sachs to General Watson on May 15th, 1940 discussed that it had been found that the carbon absorption was much lower than had been previously thought and that the probability of carbon being satisfactory as a moderator was therefore much more plausible.^23.5

With Sachs actively looking for a sizable ore supply, on June 1st, 1940, Sachs, Briggs, and Urey met with Admiral Bowen to discuss approaching officials of the Union Manière of the Belgian Congo. Shortly after this discussion, Sachs did approach them.

The NDRC

To counsel the Advisory Committee on Uranium, Briggs called together a special advisory group at the National Bureau of Standards on June 15th, 1940. This meeting was attended by Briggs, Urey, Merle A. Tuve, Wigner, Breit, Fermi, Szilard, and Pegram. The recommendation of the group to the Advisory Committee on Uranium was that funds should be sought to support research on the uranium-carbon experiment along two lines: First, further measurements of the nuclear constants involved in the proposed type of reaction. Second, experiments with amounts of uranium and carbon equal to about one-fifth to one quarter of the amount that could be estimated as the minimum in which a chain reaction would sustain itself.^23.5

“It was estimated that about $40,000 would be necessary for further measurements of the fundamental constants and that approximately $100,000 worth of metallic uranium and pure graphite would be needed for the intermediate experiment.”^23.6

At the suggestion of Dr. Vannevar Bush, President Roosevelt set up the NDRC by executive action in June 1940 to give science advice to the President and organize American science for war. The NDRC was to be similar to the National Advisory Committee for Aeronautics (NACA), but be empowered “to correlate governmental and civil research in fields of military importance outside of aeronautics. It should form a definite link between the military service themselves, and it should exist primarily to aid these services…”^21.1

In February 1940, Otto Frisch and Rudolph Peierls at Birmingham University, England, concluded that a uranium bomb made from nearly pure uranium-235 and fissioned by fast neutrons would have a critical mass of about one kilogram. Such a bomb made with 5 kg of uranium-235 was calculated to have an explosive power equivalent to several thousand tons of dynamite. This was in contrast to earlier calculations based on natural uranium (0.7% uranium- 235) fissioned by thermal (slow) neutrons, which indicated that a bomb mass of tens of tons of uranium was required to achieve criticality. As a result of the Frisch-Peierls memorandum^17.1 describing this conclusion, the British formed the MAUD Committee to investigate atomic-weapon matters.^4.1 The name “MAUD,” adopted as the code name for the British committee looking into the feasibility of producing an atomic bomb, is actually not an acronym. Instead, “Maud” is the name of a former governess employed by Danish physicist Niels Bohr.^25.1

In April, 1940, a meeting of the Division of Physical Sciences of the National Research Council, Gregory Breit proposed formation of a censorship committee to control publication in all American scientific journals. Although the reason for this suggestion was primarily the desire to control publication of papers on uranium fission, the “Reference Committee” as finally set up later that spring in the National Research Council, was a general one, and was organized to control publication policy in all fields of possible military interest.^{13.2, 23.3}

The next meeting of the Advisory Committee on Uranium was on April 28, 1940 and was attended by: Sachs, Wigner, George B. Pegram, Fermi, Szilard, Briggs, Admiral H. G. Bowen, Colonel Adamson, and Commander Hoover.
 

MAUD Committee:7.1 Sir George Thomson (Chairman) E. Bretscher Sir James Chadwick Sir John Cockcroft N. Feather Otto R. Frisch Klaus Fuchs Rudolf Peierls Sir Frederick Simon H. Halban L. Kowarski

S-1 Executive Committee: James B. Conant (President of Harvard) Lyman J. Briggs (National Bureau of Standards) Eger V. Murphree (Vice President of the Standard Oil Development Company) Arthur Holly Compton (University of Chicago Metallurgical Laboratory “Met Lab”) Earnest O. Lawrence (University of California Radiation Laboratory “Rad Lab”) Harold Clayton Urey (Columbia University Laboratory of Special Alloyed Materials “SAM”)

In June, 1940, a committee was formed at the proposal of Harold Urey and Vannevar Bush to be an advisory board of scientific experts to counsel the President’s Committee on Uranium (the Advisory Committee on Uranium). This new advisory committee to the Advisory Committee on Uranium consisted of, Harold Urey , George Pegram, Merle Tuve, Jesse Beams, Ross Gunn, and Gregory Breit^21.1

SECTION 2 – Formation

1941

March 1941 – The Frisch-Peierls prediction received a major validation in March 1941, when the results of measurements of the fast-neutron cross-section of uranium-235 by Merle Antony Tuve’s group at the Carnegie Institution of Washington were provided to Peierls in England. Peierls then calculated a critical mass of uranium of 9 kg and a “tamped” optimally efficient critical mass of 10 kg. Assuming 2% efficiency, such a bomb would have an explosive power of about 1800 tons of TNT. Peierls therefore concluded that an atomic bomb was feasible if uranium-235 could be produced in high enrichments.

April 1941 – Vannevar Bush was informed of the extent of British interest in an atomic bomb by an NDRC representative (potentially R. H. Fowler)^7.1 in London who had attended a MAUD Committee Meeting. The draft MAUD Committee report was provided to Bush in early July 1941.^4.1

President Roosevelt established the Office of Scientific Research and Development (OSRD) on June 28th 1941^22.1

November 1941 – National Academy of Sciences (NAS) Committee (chaired by Arthur H. Compton of the University of Chicago) reviewing the U.S. uranium program (at the request of Bush) recommended an expanded atomic-bomb program that used uranium-235 as the fissionable material. [It took the committee three tries (three reports), with new committee members added (at the suggestion of Bush) after each of the first two reports, to give Bush the recommendation he wanted.^4.1

In June 1942 Colonel James C. Marshall was summoned to the Main Navy and Munitions Building in Washington D.C. by Army Corps of Engineers Chief, Lieutenant General Eugene Reybold. He was given a folder from General Styer labeled “S-1“, to review while he was staying at the Willard Hotel. The next day he drove to New York City for an early morning conference with Colonel Dunn, the Division Engineer. After returning to Washington D.C. he was briefed by Styer and a separate session with Robins and Groves at the Chief’s Office. Styer spoke about the contents of the S-1 folder that detailed out that he had a new job to form an Engineer district to construct industrial plants for an atomic fission bomb. The folder indicated there had been four possible methods of quality production of both Uranium as U235 and Plutonium as P239, putting the cost at roughly $90,000,000.^3.1

“I spent the night without sleep trying to figure out what this was all about … I had never heard of atomic fission, but I did know that you could not build much of a plant, much less four of them, for $90,000,000” – Colonel James C. Marshall^3.1

The next day he spoke with both Styer and Dr. Vannevar Bush, the director of the OSRD about the details of what had been learned from the research effort within S-1. Scientists claimed to know how to theoretically produce the fissionable material, yet at the time none had been produced. Three methods had been chosen to pursue as the best avenues of approach, electromagnetic separation, gaseous diffusion, or centrifugal methods of removing U235 from its heavier and more naturally abundant isotope U238. Plutonium could be produced by bombarding uranium with neutrons^3.1

During his first week as engineer of the still nameless district, Colonel Marshall conferred with more than a dozen people, traveled more than a thousand miles, blocked out a course of action, and started organizing. After going over Dr. Vannevar Bush’s somewhat nebulous construction plans for a plutonium pilot plant and experiment station near Chicago, a heavy water production unit at Trail, British Columbia, and a giant industrial complex in the Tennessee Valley, he began exploring the priorities and power angles and laying the groundwork for bringing in Stone & Webster as overall AEM. At Lt. General Reybold’s suggestion, Colonel Marshall opened temporary headquarters in the New War Building and commenced lining up personnel. Familiar with experienced staff at the Syracuse district, Colonel Marshall chose Lt. Colonel Kenneth D. Nichols on 19 June 1942, who was the area engineer at the Pennsylvania Ordnance Works. Also chosen was Virginia J. Olsson as secretary, Charles Vanden Bulck as an administrative assistant, and Captain Robert C. Blair, a capable civil engineer.^3.2

U235

P239

The 9812th Technical Service Unit; Civil Engineering (TSU-CE) was assigned under the Corps of Engineers, Chief of Engineers to be responsible for the military phase of the Manhattan district and all military personnel were assigned to this unit.^16.1 (There were 3,353 positions available as of 27 November 1945)^16.2

In the summer of 1942 it was evident to the S-1 Committee that more positive action would soon be required and Arthur H. Compton, as head of the Metallurgical Laboratory, invited Dr. J. Robert Oppenheimer from Berkeley to Chicago to undertake the actual design of the weapons, which Gregory Breit had been assigned to do up to that point.^15.1

Y-12, home of the electromagnetic plant, was closest to Oak Ridge Tennessee within the Clinton Engineer Works. Further south and west of Oak Ridge was the X-10 area, which contained the experimental plutonium pile and separation facilities, and K-25, site of the gaseous diffusion plant and later the S-50 thermal diffusion plant.^11.1

Spring

The X-10 reactor was a cube, 24’x24’x24′, made of thousands of pieces of graphite, supplied by the National Carbon Company and the Speer Carbon Company. The pile was air cooled, and the uranium was placed in aluminum cylinders four inches long and one inch in diameter. The control rods were boron steel. The reactor was constructed and installed by E. I. du Pont de Nemours and Company without profits or patent rights. The pilot reactor began to operate 3 November 1943. The reactors at Hanford were larger and they were water cooled by tapping the Columbia River. With each reactor there had to be a chemical plant to separate the plutonium from the uranium.^15.1

By March 1944, the pilot X-10 graphite reactor at Oak Ridge was producing several grams of plutonium a month.^15.1

Robert Frederick Christy was a member of the Theoretical Division’s Implosion Dynamics Group. Christy proposed the use of a solid core of plutonium with an initiator and a “pusher” that would compensate for possible asymmetries during implosion rather thana hollow shell, which had been the initial choice. These features were adopted, and the design became known as the Christy gadget or Christy pit. On February 28, 1945, Oppenheimer and Groves decided provisionally on Christy’s core design, using electric detonators and explosive lenses made of the explosives Composition B and Baratol.^18.1

Section X – Heavy Water Production

Harold Urey, then at Columbia University, and his associate George Murphy in 1931 demonstrated the existence of deuterium. The Norsk Hydro plant in Vemork, Norway, the largest electrolytic hydrogen plant in the world in the 1930s, was producing heavy water by 1934. Historical documents show that the Norwegian plant shipped heavy water to researchers around the world, including Harold Urey at Columbia.^20.1

By 1940, interest in heavy water heightened as scientists began to research its potential as a neutron moderator. A research and development program established at Columbia University under Urey began to investigate how heavy water could be mass-produced. This research, under the auspices of the OSRD, was carried out at other American universities and in industrial research laboratories as well.^20.1

After obtaining funding, Urey set up a pilot plant in Louisiana that was operated by the Standard Oil Company. The pilot plant was charged with studying the liquid-gas phase exchange reaction under high-pressure, while Urey worked on developing a catalyst. Heavy water research continued, but the effort moved from Louisiana to Canada. In a cooperative effort between the United States, Britain, and Canada, Harold Urey worked with Hans von Halban, who was to head a heavy water research program for the British. The program was located at Trail British Columbia, near the American-Canadian border. An existing hydro-powered , electrolytic-hydrogen plant for ammonia production was in operation at Trail, owned by Consolidated Mining and Smelting Company of Canada LTD (Cominco). Cominco converted a loop in their ammonia plant for heavy water production. By mid-June the plant had produced enough deuterium for Enrico Fermi to make measurement that proved that deuterium was an excellent moderator. Unfortunately, the conclusive tests occurred six months after Fermi’s success at the University of Chicago’s Stagg Field. Once CP-1, the first graphite-moderated reactor, went into operation, heavy water research was “relegated to a secondary role as the moderator for the second generation of nuclear reactors.”^20.1

In 1949, the Girdler Corporation, a Louisville, Kentucky-based firm, was asked to study the feasibility of converting the old Du Pont P-9 facility at the Wabash River Ordnance Works (WROW) to a low-pressure dual-temperature production plan under the guidance of the AEC‘s New York Operations Office. Given that the WROW facility was designed for vacuum operation, it could not be converted into a high-pressure production system. It was estimated that the converted plant could produce 2.5 tons of heavy water per month at lower pressures.^20.2

Section X – Trinity

Plane 110.1	Plane 210.1
A/C – Major Clyde S. Shields Pilot – Captain Richard R. Mann Bombardier – Captain David Semple Unknown – Corporal Ervin R. Rochlitz Unknown – Technical Sergeant Robert L. Blinn	A/C – Captain William F. Hartshorn Pilot – 1st Lieutenant David W. O’Harra Bombardier – Captain Robert C. Von Graffen Observer – Colonel Clifford J. Heflin

Section X – After the War

Manhattan District turns over is control of atomic energy matters to the Atomic Energy Commission on 31 December 1946. The Manhattan District was officially abolished on 15 August 1947^1.1

After the war, Roger Warner who, with Arthur Machen, had assembled the “Fat Man” weapon on Tinian, persuaded Machen to move to Sandia Base. This eventually led to the entirety of Z-Division moving to Sandia Base to train the newly established special weapons units and to prepare manuals on weapon assembly. Machen hired explosives experts from the Hercules Powder Company in Tennessee to assist with the assembly of the high-explosives lenses.^2.1

There were originally 46 SILVERPLATE B-29s, but after the war by January 1946 there were 27, and 23 by December 31st 1946.^19.1

Sandia Base

Kansas City Area Office

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