The Ames Project was a research and development project that was part of the larger
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
to build the first
atomic bombs during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
. It was founded by
Frank Spedding
Frank Harold Spedding (22 October 1902 – 15 December 1984) was a Canadian American chemist. He was a renowned expert on rare earth elements, and on extraction of metals from minerals. The uranium extraction process helped make it possible for ...
from
Iowa State College
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...
in
Ames, Iowa as an offshoot of the
Metallurgical Laboratory at the
University of Chicago
The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
devoted to
chemistry and
metallurgy, but became a separate project in its own right. The Ames Project developed the
Ames Process, a method for preparing pure uranium metal that the Manhattan Project needed for its atomic bombs and
nuclear reactor
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...
s. Between 1942 and 1945, it produced over of uranium metal. It also developed methods of preparing and casting
thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high ...
,
cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the +3 ...
and
beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form m ...
. In October 1945 Iowa State College received the
Army-Navy "E" Award
The Army-Navy "E" Award was an honor presented to companies during World War II whose production facilities achieved "Excellence in Production" ("E") of war equipment. The award was also known as the Army-Navy Production Award. The award was cr ...
for Excellence in Production, an award usually only given to industrial organizations. In 1947 it became the
Ames Laboratory
Ames National Laboratory, formerly Ames Laboratory, is a United States Department of Energy national laboratory located in Ames, Iowa, and affiliated with Iowa State University. It is a top-level national laboratory for research on national sec ...
, a
national laboratory under the
Atomic Energy Commission.
Background
The discovery of the
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
by
James Chadwick
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...
in 1932, followed by that of
nuclear fission by German chemists
Otto Hahn
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...
and
Fritz Strassmann
Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the ke ...
in 1938, and its theoretical explanation (and naming) by
Lise Meitner and
Otto Frisch soon after, opened up the possibility of a controlled
nuclear chain reaction with
uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
. On 20 December 1941, soon after the
Japanese attack on Pearl Harbor
The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawaii, ju ...
that brought the United States into
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
, the
Nobel Prize
The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...
-winning physicist
Arthur H. Compton was placed in charge of the
plutonium
Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibi ...
project, the objective of which was to produce reactors to convert uranium into plutonium, to find ways to chemically separate plutonium from the uranium, and ultimately to design and build an
atomic bomb. This became the
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
. Although a successful reactor had not yet been built, the scientists had already produced several different but promising design concepts.
Compton established the project's
Metallurgical Laboratory at the
University of Chicago
The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
in February 1942. Its mission was to build
nuclear reactor
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...
s to create plutonium that would be used in atomic bombs. For advice on assembling the laboratory's Chemistry Division, Compton, a physicist, turned to
Herbert McCoy, who had considerable experience with
isotopes
Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) ...
and radioactive elements. McCoy recommended
Frank Spedding
Frank Harold Spedding (22 October 1902 – 15 December 1984) was a Canadian American chemist. He was a renowned expert on rare earth elements, and on extraction of metals from minerals. The uranium extraction process helped make it possible for ...
from
Iowa State College
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...
in
Ames, Iowa, as an expert on the
rare-earth element
The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides ( yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silv ...
s, which were chemically similar to the
actinide
The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The info ...
series that included uranium and plutonium. Compton asked Spedding to become the head of the Metallurgical Laboratory's Chemistry Division.
Owing to a lack of space at the University of Chicago, Spedding proposed to organize part of the Chemistry Division at Iowa State College, where he had colleagues who were willing to help. It was agreed that Spedding would spend half of each week in Ames, and half in Chicago. The intention was that staff at Ames would eventually move to Chicago when space became available, but this never happened. The success of the Ames Project ensured that it became a separate laboratory within the Manhattan Project.
Organization
Spedding started by recruiting two fellow scientists at Iowa State College to become his associate directors;
Harley A. Wilhelm, an expert in
spectrochemistry and metallurgy, as the head of the Ames Project's Metallurgy Division, and Iral B. Johns as the head of the Plutonium Division. Under them were eight section chiefs. The Ames Project grew to over 90 scientific staff. The total number of staff eventually exceeded 500. Senior staff would meet on Sunday mornings to review the previous week's work and set goals for the week ahead, a process that came to be called "Speddinars". At first Spedding had to depart for Chicago soon after each meeting, but in early 1943 he was succeeded as head of the chemistry division at the Metallurgical Laboratory by
James Franck
James Franck (; 26 August 1882 – 21 May 1964) was a German physicist who won the 1925 Nobel Prize for Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed his doctorate i ...
, allowing Spedding to spend more time at Ames. He remained an associate director at the Metallurgical Laboratory.
Spedding was fortunate in having the full support of
Charles E. Friley, the president of Iowa State College, even though the nature of the work could not at first be disclosed to him while security checks were being undertaken. Once these were completed, Friley brought in Harold V. Gaskill, the Dean of Science, as the Ames Project's administrator. The
took control of the Manhattan Project in June 1942, and the Ames Project in late 1942.
Uranium
Ames Process
The first item on the agenda was to find uranium for the nuclear reactor that
Enrico Fermi was proposing to build. Uranium ore was readily available. Some of high-grade ore from the
Belgian Congo
The Belgian Congo (french: Congo belge, ; nl, Belgisch-Congo) was a Belgian colony in Central Africa from 1908 until independence in 1960. The former colony adopted its present name, the Democratic Republic of the Congo (DRC), in 1964.
Colo ...
was in storage in a warehouse at
Port Richmond on
Staten Island. About per annum was being mined at the
Eldorado Mine at
Port Radium
Port Radium is a mining area on the eastern shore of Great Bear Lake, Northwest Territories, Canada.
It included the settlement of Cameron Bay as well as the Eldorado (also called Port Radium) and Echo Bay mines. The name Port Radium did n ...
on the
Great Bear Lake
Great Bear Lake ( den, Sahtú; french: Grand lac de l'Ours) is a lake in the boreal forest of Canada. It is the largest lake entirely in Canada (Lake Superior and Lake Huron are larger but straddle the Canada–US border), the fourth-largest ...
near the Arctic Circle in Canada's
Northwest Territories. The
Eldorado
El Dorado (, ; Spanish for "the golden"), originally ''El Hombre Dorado'' ("The Golden Man") or ''El Rey Dorado'' ("The Golden King"), was the term used by the Spanish in the 16th century to describe a mythical tribal chief (''zipa'') or king o ...
company also operated a refinery at
Port Hope, Ontario
Port Hope is a municipality in Southern Ontario, Canada, approximately east of Toronto and about west of Kingston. It is located at the mouth of the Ganaraska River on the north shore of Lake Ontario, in the west end of Northumberland County. ...
, where Canadian and Belgian ore was refined. The Manhattan Project's estimated requirements for 1942 were , of which Compton required just for his proposed nuclear reactor.
The major problem was impurities in the uranium oxide, which could act as
neutron poison
In applications such as nuclear reactors, a neutron poison (also called a neutron absorber or a nuclear poison) is a substance with a large neutron absorption cross-section. In such applications, absorbing neutrons is normally an undesirable eff ...
s and prevent a nuclear chain reaction. Due to the presence of impurities, references published before 1942 typically listed its melting point at around when pure uranium metal actually melts at . Peter P. Alexander, at Metal Hydrides Incorporated, gave in 1938 the first indications that the melting point of uranium was "as low as and even somewhat lower".
The most effective way to purify uranium oxide in a laboratory was to take advantage of the fact that
uranium nitrate is soluble in
ether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be ...
. Scaling this process up for industrial production was a dangerous proposition; ether was explosive, and a factory using large quantities was likely to blow up or burn down. Compton and Spedding turned to
Mallinckrodt
Mallinckrodt Pharmaceuticals is an American-Irish domiciled manufacturer of specialty pharmaceuticals (namely, adrenocorticotropic hormone), generic drugs and imaging agents. In 2017 it generated 90% of its sales from the U.S. healthcare system. ...
in
Saint Louis, Missouri, which had experience with ether. Spedding went over the details with Mallinckrodt's chemical engineers, Henry V. Farr and John R. Ruhoff, on 17 April 1942. Within a few months, sixty tons of highly pure uranium oxide was produced.
The only uranium metal available commercially was produced by the
Westinghouse Electric and Manufacturing Company
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
, using a photochemical process. Uranium oxide was reacted with
potassium fluoride
Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare ...
in large vats on the roof of Westinghouse's plant in
Bloomfield, New Jersey
Bloomfield is a township in Essex County, New Jersey, United States. As of the 2020 United States Census, the township's population was 53,105. It surrounds the Bloomfield Green Historic District.
History
The initial patent for the land that w ...
. This produced ingots the size of a
quarter A quarter is one-fourth, , 25% or 0.25.
Quarter or quarters may refer to:
Places
* Quarter (urban subdivision), a section or area, usually of a town
Placenames
* Quarter, South Lanarkshire, a settlement in Scotland
* Le Quartier, a settlement ...
that were sold for around $20 per gram. But
Edward Creutz, the head of the Metallurgical Laboratory's group responsible for fabricating the uranium, wanted a metal sphere the size of an orange for his experiments. With Westinghouse's process, it would have cost $200,000 and taken a year to produce. The hydride or "hydramet" process, developed by Alexander used
calcium hydride
Calcium hydride is the chemical compound with the formula , and is therefore an alkaline earth hydride. This grey powder (white if pure, which is rare) reacts vigorously with water liberating hydrogen gas. is thus used as a drying agent, i.e. a d ...
as the
reducing agent
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ).
Examples of substances that are commonly reducing agents include the Earth me ...
for the conversion of uranium ore to metal. By this means the Metal Hydrides plant in
Beverly, Massachusetts, managed to produce a few pounds of uranium metal. Unfortunately, the calcium hydride contained unacceptable amounts of
boron, a neutron poison, making the metal unsuitable for use in a reactor. Some months would pass before Clement J. Rodden from the
National Bureau of Standards
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
and
Union Carbide
Union Carbide Corporation is an American chemical corporation wholly owned subsidiary (since February 6, 2001) by Dow Chemical Company. Union Carbide produces chemicals and polymers that undergo one or more further conversions by customers befo ...
figured out a means to produce sufficiently pure calcium hydride.
Spedding and Wilhelm began looking for ways to create the uranium metal. At the time, it was produced in the form of a powder, and was highly
pyrophoric
A substance is pyrophoric (from grc-gre, πυροφόρος, , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolit ...
. It could be pressed and
sintered and stored in cans, but to be useful, it needed to be melted and cast. Casting presented difficulty because uranium corroded
crucible
A crucible is a ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures. While crucibles were historically usually made from clay, they can be made from any material that withstands te ...
s of beryllium, magnesia and graphite. To produce uranium metal, they tried reducing uranium oxide with hydrogen, but this did not work. While most of the neighboring elements on the
periodic table can be reduced to form pure metal and
slag, uranium did not behave this way. In June 1942 they then tried reducing the uranium with carbon in a hydrogen atmosphere, with only moderate success. They then tried aluminum, magnesium and calcium, all of which were unsuccessful. The following month the Ames team found that molten uranium could be cast in a
graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...
container. Although graphite was known to react with uranium, this could be managed because the carbide formed only where the two touched.
Around this time, someone from the Manhattan Project's
Berkeley Radiation Laboratory brought a cube of
uranium tetrafluoride
Uranium tetrafluoride is the inorganic compound with the formula UF4. It is a green solid with an insignificant vapor pressure and low solubility in water. Uranium in its tetravalent ( uranous) state is important in various technological process ...
—the uranium compound being used in the
calutron
A calutron is a mass spectrometer originally designed and used for separating the isotopes of uranium. It was developed by Ernest Lawrence during the Manhattan Project and was based on his earlier invention, the cyclotron. Its name was derive ...
s—to the Metallurgical Laboratory to discuss the possibility of using it rather than uranium oxide in the reactor. Spedding began wondering whether it would be possible to produce uranium metal from this
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...
, bypassing the problems with oxygen. He took the cube back to Ames, and asked Wilhelm to investigate. The task was assigned to an associate, Wayne H. Keller. He investigated a process (now known as the
Ames process) originally developed by J. C. Goggins and others at the
University of New Hampshire
The University of New Hampshire (UNH) is a public land-grant research university with its main campus in Durham, New Hampshire. It was founded and incorporated in 1866 as a land grant college in Hanover in connection with Dartmouth College, m ...
in 1926. This involved mixing
uranium tetrachloride
Uranium tetrachloride is an inorganic compound, a salt of uranium and chlorine, with the formula UCl4. It is a hygroscopic olive-green solid. It was used in the electromagnetic isotope separation (EMIS) process of uranium enrichment. It is one o ...
and
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
metal in a
calcium oxide
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime''" connotes calcium-containing inorganic ...
-lined steel pressure vessel (known as a "bomb") and heating it. Keller was able to reproduce Goggin's results on 3 August 1942, creating a button of very pure uranium metal. The process was then scaled up. By September, bombs were being prepared in steel pipes long, lined with
lime
Lime commonly refers to:
* Lime (fruit), a green citrus fruit
* Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide
* Lime (color), a color between yellow and green
Lime may also refer to:
Botany ...
to prevent corrosion, and containing up to of uranium tetrafluoride. C. F. Gray took these ingots and cast them into a billet of pure uranium.
Production
On 24 September 1942, Wilhelm took the ingot to Spedding at the Metallurgical Laboratory in Chicago and presented it to Compton, whose first reaction was of disbelief. He thought it must be hollow. Spedding had the ingot cut open. It was not hollow. A few days later, the Metallurgical Laboratory's director, Richard L. Doan, went to Ames, where he drew up an
Office of Scientific Research and Development
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1 ...
(OSRD) contract for the Ames Project to produce of pure uranium metal a day. This would be a pilot plant, with the process eventually being transferred to industry. The OSRD contract was superseded by a Manhattan Project contract in November 1942. The initial contract was for $50,000. By 31 December 1945, the face value of contracts let to the Ames Project totaled $6.907 million; but the work was carried out for $4 million.
Wilhelm found an old wooden building on the southeastern edge of the campus. It had been a home economics building until 1926, and then had served as a women's gymnasium until a new one was built in 1941; by 1942 it was mainly used for storage. The building was handed over to the Ames Project, and the wooden floor replaced with a concrete one, much to the disappointment of the university architect, who had been trying for some years to get the place torn down. The building officially became known as the Physical Chemistry Annex; local people called it "Little Ankeny", after the nearby town of
Ankeny, Iowa
Ankeny (, ) is a city in Polk County, Iowa, United States and a suburb of the state capital of Des Moines, as part of the Des Moines-West Des Moines, IA metropolitan statistical area.
As of the 2020 census, the population of Ankeny was 67,887, ...
, where there was an ordnance plant. Looking for machine tools, Wilhelm found a machine shop for sale in Ames. The owner, Bill Maitland, had once made gardening tools, but could no longer obtain the metal he needed due to wartime rationing. Wilhelm bought it for $8,000. The Metallurgical Laboratory supplied two large 40-
kilowatt reduction furnaces.
The Ames Project supplied two tons of uranium metal to the Metallurgical Laboratory for the construction of
Chicago Pile-1, the world's first nuclear reactor, which achieved
criticality on 2 December 1942. The Ames Project would later supply over 90 percent of the uranium for the
X-10 Graphite Reactor at the
Clinton Engineer Works
The Clinton Engineer Works (CEW) was the production installation of the Manhattan Project that during World War II produced the enriched uranium used in the 1945 bombing of Hiroshima, as well as the first examples of reactor-produced pluton ...
in
Oak Ridge, Tennessee. Production rose from of uranium metal per day in December 1942 to per day by the middle of January 1943.
For production, the process was changed to use magnesium instead of calcium; magnesium was cheaper, more readily available, and purer. But it was also harder to start the reaction with magnesium than calcium, requiring more heating. The uranium tetrafluoride, known as green salt because of its characteristic color, was supplied by Mallinckrodt,
DuPont and Harshaw Chemical, and was ground up on arrival, as was the magnesium. Bombs were normally pipes, long, although pipes, long, could be used to produce ingots. They were heated to for 40 to 60 minutes, after which the mixture spontaneously reacted, reaching temperatures of . A microphone was used to detect the ignition, and the bomb would be moved to a spray chamber to cool. If everything worked, uranium metal biscuit and
magnesium fluoride
Magnesium fluoride is an inorganic compound with the formula MgF2. The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics that are also used in space telescopes. It occurs natur ...
slag would be produced. After the bomb cooled, it would be opened and hammered until the two separated. The resulting biscuit would be stamped, and sent off to be cast.
Casting re-shaped the uranium into ingots and removed impurities. The metal biscuits were melted in a graphite crucible and poured into a mold. This produced rods between in diameter and long. The rods were stamped with a number and placed in wooden boxes for shipping to the Metallurgical Laboratory. From there they were sent to the Oak Ridge or the
Hanford Site
The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including SiteW a ...
. By July 1943, the Ames Project was producing of uranium metal per month. The cost of a pound of uranium metal fell from $1,000 to around one dollar. Starting in July 1943, Mallinckrodt, Electromet, and DuPont began producing uranium by the Ames process, and Ames phased out its own production by early 1945.
The Ames Project began a program of recovering uranium metal from scrap. A new building, known as Physical Chemistry Annex 2, was constructed for the purpose in 1944. Uranium turnings were washed, dried, passed through a magnet to remove iron impurities, and pressed into briquettes. They were then sent to be remelted. The job was handed over to Metal Hydrides and a recovery plant at the Hanford Site in December 1945, by which time the Ames Project had recovered of scrap metal. In all, the Ames Project produced over of uranium metal. All production ceased on 5 August 1945, as did that at Metal Hydrides and DuPont, leaving Mallinckrodt as the only producer of uranium metal in the early post-war period.
Other metals
Beginning in 1942, along with uranium production operations, the Ames Project conducted a variety of metallurgical research related to the separation and purification of thorium, beryllium and rare-earth metals, such as cerium.
Thorium
In 1942,
Glenn T. Seaborg
Glenn Theodore Seaborg (; April 19, 1912February 25, 1999) was an American chemist whose involvement in the synthesis, discovery and investigation of ten transuranium elements earned him a share of the 1951 Nobel Prize in Chemistry. His work i ...
established that when
thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high ...
was bombarded with neutrons, it could be transformed into
fissile
In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be t ...
uranium-233
Uranium-233 (233U or U-233) is a fissile isotope of uranium that is bred from thorium-232 as part of the thorium fuel cycle. Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It has been used successfully in exp ...
. This was another possible route to an atomic bomb, especially if it turned out that uranium-233 could be more easily separated from thorium than plutonium from uranium. It was not pursued further because uranium-233 production would have required a complete redesign of the Hanford reactors; but in April 1944 the Metallurgical Laboratory's Thorfin R. Rogness calculated that a nuclear reactor containing thorium could produce enough uranium-233 to sustain its reaction without adding anything but more thorium. This was very interesting, because at the time it was thought that uranium might be scarce, whereas thorium was at least ten times more plentiful.
In July and August 1943, the Ames Project attempted to create thorium metal using something similar to the Ames Process. This was unsuccessful, because thorium has a much higher melting point than uranium. Efforts continued into 1944, and it was found that with a
zinc chloride
Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. This salt is hygroscopic and e ...
booster they could produce a zinc-thorium
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...
. Heating to in a graphite crucible could then melt the zinc, which could be drawn off. This left the thorium, which was cast into ingots in beryllia crucibles. Some was produced by 31 December 1945. Thorium sold for $3 a gram before the war; by its end, the Ames Project was producing it for less than 5¢ a gram.
Beryllium
Beryllium was used by the Manhattan Project as a
neutron reflector
A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, tungsten carbide, gold, or other materials. A neutron reflector ...
, and as a component of
modulated neutron initiator
A modulated neutron initiator is a neutron source capable of producing a burst of neutrons on activation. It is a crucial part of some nuclear weapons, as its role is to "kick-start" the chain reaction at the optimal moment when the configuration i ...
s. Only one firm produced it commercially in the United States, Brush Beryllium in
Lorain, Ohio. The Ames Project began working on a production process in December 1943, reducing
beryllium fluoride
Beryllium fluoride is the inorganic compound with the formula Be F2. This white solid is the principal precursor for the manufacture of beryllium metal. Its structure resembles that of quartz, but BeF2 is highly soluble in water.
Properties
B ...
in a bomb with metallic magnesium and a sulphur booster. The main difficulty with working with beryllium was its high toxicity. A closed bomb was used to minimize the possibility of producing toxic beryllium dust. The process worked, but the high temperatures and pressures created by the magnesium sulphide meant that it was potentially explosive. An alternative was then developed using beryllium fluoride in a bomb with metallic calcium and a
lead chloride booster. The metal was
cast in a vacuum. Research was still ongoing when the war ended.
Cerium
In mid-1944, the Ames Project was asked to produce cerium. This was being used by the laboratories at Berkeley and
Los Alamos for
cerium sulphide, which was used in crucibles to cast plutonium. Again, the bomb method was used, this time to reduce anhydrous
cerium chloride with calcium using an iodine booster. A special "dry room" was constructed for drying out the cerium chloride using
hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
gas. The resulting metal contained calcium and magnesium impurity, so it had to be recast to remove them. The opportunity was taken to make it into diameter rods long, the desired shape. Because cerium is so reactive, the remelting was done in a vacuum, using a
calcium oxide
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime''" connotes calcium-containing inorganic ...
or
magnesium oxide
Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...
crucible. The first shipment of cerium metal was made in August 1944. The Ames Laboratory produced of extremely (more than 99%) pure cerium by August 1945, when production ended.
Alloys
Since uranium metal had been so scarce before the war, little was known about its metallurgy, but with uranium being used in the reactors, the Manhattan Project became keenly interested in its properties. In particular, with water being used for cooling, there was speculation about alloys with high thermal conductivity and resistance to corrosion. The Ames Project produced and tested
uranium carbide
Uranium carbide, a carbide of uranium, is a hard refractory ceramic material. It comes in several stoichiometries (''x'' differs in ), such as uranium methanide (UC, CAS number 12070-09-6), uranium sesquicarbide (U2C3, CAS number 12076-62-9),
a ...
, which had a potential to be used as a fuel in reactors instead of metallic uranium. So too was
bismuth
Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs ...
, because of its low
neutron capture
Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, ...
cross section
Cross section may refer to:
* Cross section (geometry)
** Cross-sectional views in architecture & engineering 3D
*Cross section (geology)
* Cross section (electronics)
* Radar cross section, measure of detectability
* Cross section (physics)
**Abs ...
, so the Ames Project produced and tested uranium-bismuth alloys.
At one point a proposal was on the table to protect the uranium in a reactor from corrosion by jacketing it with
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
. The Ames Project therefore studied uranium-copper alloys, which would occur where the uranium met the copper jacket. In practice, the uranium was canned in aluminum; this too was studied, as were alloys with tin, which was used to solder the cans. Tests were also carried out with alloys of uranium with beryllium, calcium, cobalt, magnesium, manganese and thorium, which were being produced or in use elsewhere in the Ames Project. Attempts were made to separate plutonium from uranium through metallurgy, exploiting plutonium's greater affinity with gold and silver, but the Manhattan Project chose to use the
bismuth phosphate process, a chemical separation method, instead.
The Ames Project also studied thorium, alloying it with bismuth, carbon, chromium, iron, manganese, molybdenum, nickel, oxygen, tin, tungsten and uranium, and alloyed beryllium with bismuth, lead, thorium, uranium and zinc.
Chemistry
The chemistry of uranium was the focus of multiple studies by the Ames Project. The properties of the various
uranium oxide
Uranium oxide is an oxide of the element uranium.
The metal uranium forms several oxides:
* Uranium dioxide or uranium(IV) oxide (UO2, the mineral uraninite or pitchblende)
* Diuranium pentoxide or uranium(V) oxide (U2O5)
* Uranium trioxide o ...
s and
uranium hydride
Uranium hydride, also called uranium trihydride (UH3), is an inorganic compound and a hydride of uranium.
Properties
Uranium hydride is a highly toxic, brownish grey to brownish black pyrophoric powder or brittle solid. Its density at 20 ° ...
were investigated. The latter of was particular interest because at one point the Los Alamos Laboratory considered using it in an atomic bomb instead of metallic uranium, but the idea was found to be inefficient, and was shelved. A process was developed to recovery
depleted uranium metal from the uranium tetrafluoride left over from the
electromagnetic
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...
isotope separation
Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes. The use of the nuclides produced is varied. The largest variety is used in research (e.g. in chemistry where atoms of "marker" n ...
process and
uranium hexafluoride
Uranium hexafluoride (), (sometimes called "hex") is an inorganic compound with the formula UF6. Uranium hexafluoride is a volatile white solid that reacts with water, releasing corrosive hydrofluoric acid. The compound reacts mildly with alumin ...
left over from the
gaseous diffusion
Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride (UF6) through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 (235U) and uranium-2 ...
process. This was operated as a pilot plant that produced kilogram quantities, before being turned over to the Manhattan Project's
SAM Laboratories for implementation on an industrial scale at Oak Ridge.
If the chemistry and metallurgy of uranium was poorly understood, that of plutonium was practically unknown, as it had only existed in microscopic amounts. Samples began arriving from the reactors in 1943, and although the locus of the Manhattan Project's investigations into plutonium chemistry was at the Metallurgical Laboratory, the Ames Project investigated methods of separating plutonium metal from uranium and
fission products.
Post-war
Major General
Major general (abbreviated MG, maj. gen. and similar) is a military rank used in many countries. It is derived from the older rank of sergeant major general. The disappearance of the "sergeant" in the title explains the apparent confusion of ...
Leslie R. Groves Jr.
Lieutenant general (United States), Lieutenant General Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers Officer (armed forces), officer who oversaw the construction of the Pentagon and di ...
, the director of the Manhattan Project, visited Iowa State College on 12 October 1945, and presented the
Army-Navy "E" Award
The Army-Navy "E" Award was an honor presented to companies during World War II whose production facilities achieved "Excellence in Production" ("E") of war equipment. The award was also known as the Army-Navy Production Award. The award was cr ...
for Excellence in Production for its part in producing uranium for the Manhattan Project. It was unprecedented for a college or university to receive this award, which was usually given to industrial organizations. The award came in the form of a banner sporting four white stars, representing two and a half years of service to the war effort. , the award was on display at Iowa State University in Spedding Hall.
The Iowa State Board of Education created the Institute of Atomic Research (IAR) as a coordinating body for research throughout the
Midwestern United States
The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...
on 1 November 1945, with Spedding as its director. The Manhattan Project continued to fund the activities of the Ames Project, but with the passage of the
Atomic Energy Act of 1946, responsibility passed to the newly created
Atomic Energy Commission (AEC) on 1 January 1947.
On 17 May 1947, the AEC awarded the contract to run the
Ames Laboratory
Ames National Laboratory, formerly Ames Laboratory, is a United States Department of Energy national laboratory located in Ames, Iowa, and affiliated with Iowa State University. It is a top-level national laboratory for research on national sec ...
, which now had the status of a
national laboratory, to Iowa State College. The laboratory remained on the Iowa State College campus, and its faculty and graduate students made up most of the staff. Spedding remained its director until he retired in 1968. Administration was delegated to the IAR. Permanent buildings were constructed that were opened in 1948 and 1950, and subsequently named Wilhelm Hall and Spedding Hall. The Ames Laboratory retained a focus on chemistry and metallurgy, particularly of the rare-earth metals.
Notes
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