The Dayton Project was a research and development project to produce
polonium
Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...
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 opposin ...
, as 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
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
. Work took place at several sites in and around
Dayton, Ohio
Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater Day ...
. Those working on the project were ultimately responsible for creating the polonium-based
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 which were used to begin the chain reactions in the atomic bombs.
The Dayton Project began in 1943 when
Monsanto
The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best known product is Roundup, a glyphosate-based herbicide, developed in th ...
's
Charles Allen Thomas
Charles Allen Thomas (February 15, 1900 – March 29, 1982) was a noted American chemist and businessman, and an important figure in the Manhattan Project. He held over 100 patents.
A graduate of Transylvania College and Massachusetts Institute ...
was recruited by the Manhattan Project to coordinate 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 ...
purification and production work being carried out at various sites. Scientists at the
Los Alamos Laboratory
The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Ro ...
calculated that a plutonium bomb would require a neutron initiator. The best-known neutron sources used radioactive polonium 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 mi ...
, so Thomas undertook to produce polonium at Monsanto's laboratories in Dayton. While most Manhattan Project activity took place at remote locations, the Dayton Project was located in a populated, urban area. It ran from 1943 to 1949, when the
Mound Laboratories
Mound Laboratory in Miamisburg, Ohio was an Atomic Energy Commission (later Department of Energy) facility for nuclear weapon research during the Cold War, named after the nearby Miamisburg Indian Mound.
The laboratory grew out of the World War ...
were completed in nearby
Miamisburg, Ohio
Miamisburg ( ) is a city in Montgomery County, Ohio. The population was 20,181 at the time of the 2010 census. A suburb of Dayton. It is part of the Dayton metropolitan area. Miamisburg is known for its large industry (mainly for its nuclear ...
, and the work moved there.
The Dayton Project developed techniques for extracting polonium from the
lead dioxide
Lead(IV) oxide is the inorganic compound with the formula PbO2. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applicatio ...
ore in which it occurs naturally, and from
bismuth
Bismuth is a chemical element with the Symbol (chemistry), 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 ...
targets that had been bombarded by neutrons in a
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 from nu ...
. Ultimately, polonium-based neutron initiators were used in both the
gun-type Little Boy
"Little Boy" was the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress ''Enola Gay'' p ...
and the
implosion-type Fat Man
"Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the fir ...
used in the
atomic bombings of Hiroshima and Nagasaki
The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the onl ...
respectively. The fact that polonium was used as an initiator was classified until the 1960s, but
George Koval
George Abramovich Koval ( rus, Жорж (Георгий) Абрамович Коваль, p=ˈʐorʐ (ɡʲɪˈorɡʲɪj) ɐˈbraməvʲɪtɕ kɐˈvalʲ, a=Ru-George Abramovich Koval.flac, Zhorzh Abramovich Koval; December 25, 1913 – January 31 ...
, a technician with the Manhattan Project's
Special Engineer Detachment The Special Engineer Detachment (SED) was a US Army program that identified enlisted personnel with technical skills, such as machining, or who had some science education beyond high school. Those identified were organized into the Special Engineer ...
, penetrated the Dayton Project as a spy for the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
.
Background
In December 1942, 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 opposin ...
,
Charles Allen Thomas
Charles Allen Thomas (February 15, 1900 – March 29, 1982) was a noted American chemist and businessman, and an important figure in the Manhattan Project. He held over 100 patents.
A graduate of Transylvania College and Massachusetts Institute ...
, a chemist and director of research at
Monsanto
The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best known product is Roundup, a glyphosate-based herbicide, developed in th ...
in
St. Louis
St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...
, joined the
National Defense Research Committee
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the Un ...
(NDRC) as the deputy chief of its Division 8, which was responsible for propellants, explosives and the like. Early in 1943, he traveled to the east with
Richard C. Tolman
Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an American mathematical physicist and physical chemist who made many contributions to statistical mechanics. He also made important contributions to theoretical cosmology in t ...
, a member of the NDRC, and
James B. Conant
James Bryant Conant (March 26, 1893 – February 11, 1978) was an American chemist, a transformative President of Harvard University, and the first U.S. Ambassador to West Germany. Conant obtained a Ph.D. in Chemistry from Harvard in 1916. ...
, the president of
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...
and the chairman of the NDRC, to witness a demonstration of a new underwater explosive. Conant and Tolman took the opportunity to quietly investigate Thomas' background. He was then invited to a meeting in Washington D.C., with
Brigadier General
Brigadier general or Brigade general is a military rank used in many countries. It is the lowest ranking general officer in some countries. The rank is usually above a colonel, and below a major general or divisional general. When appointed ...
Leslie R. Groves, Jr.
Lieutenant General Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a top secret research project ...
, the director of the wartime
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 ...
responsible for building an
atomic bomb
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...
. When he got there, Thomas found Conant was also present.
Groves and Conant were hoping to harness Thomas's industrial expertise for the benefit of the project. They offered him a post as a deputy to
Robert Oppenheimer
J. Robert Oppenheimer (; April 22, 1904 – February 18, 1967) was an American theoretical physicist. A professor of physics at the University of California, Berkeley, Oppenheimer was the wartime head of the Los Alamos Laboratory and is often ...
, the director of the
Los Alamos Laboratory
The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Ro ...
in New Mexico, but he did not wish to move his family or give up his responsibilities at Monsanto. Instead he accepted the role of coordinating 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 ...
purification and production work being carried out at Los Alamos, the
Metallurgical Laboratory
The Metallurgical Laboratory (or Met Lab) was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and m ...
in Chicago,
Radiation Laboratory
The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. It was first created in October 1940 and operated until 31 ...
in Berkeley, and
Ames Laboratory
Ames National Laboratory, formerly Ames Laboratory, is a United States Department of Energy United States Department of Energy national laboratories, national laboratory located in Ames, Iowa, and affiliated with Iowa State University. It is a t ...
in Iowa. Chemistry and metallurgy at Los Alamos would be led by the youthful
Joseph W. Kennedy
Joseph William Kennedy (May 30, 1916 – May 5, 1957) was an American chemist who was a co-discoverer of plutonium, along with Glenn T. Seaborg, Edwin McMillan and Arthur Wahl. During World War II he was head of the CM (Chemistry and Metallurgy) ...
.
At Los Alamos, physicist
Robert Serber
Robert Serber (March 14, 1909 – June 1, 1997) was an American physicist who participated in the Manhattan Project. Serber's lectures explaining the basic principles and goals of the project were printed and supplied to all incoming scientific st ...
proposed that instead of relying on spontaneous fission, the chain reaction inside the atomic bomb should be triggered by a
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 ...
. The best-known neutron sources were
radium
Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather t ...
-
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 mi ...
and
polonium
Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...
-beryllium. The latter was chosen, as polonium has a 138-day
half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...
, which made it intense enough to be useful but not long-lived enough to be stockpiled. Thomas took charge of the development of techniques to industrially refine polonium for use with beryllium in the
"urchin" internal neutron initiators. This effort became the Dayton Project.
Organization
![Dayton Project - Unit III in September 1943](https://upload.wikimedia.org/wikipedia/commons/6/6b/Dayton_Project_-_Unit_III_in_September_1943.jpg)
Thomas brought in key personnel from Monsanto's Thomas and Hochwalt Laboratories in
Dayton, Ohio
Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater Day ...
, including Caroll Hochwalt, James Lum and Nicholas Samaras. Thomas became Director of the Dayton Project, with Hochwalt as Assistant Project Director and Lum as Laboratory Director. They decided that about twelve chemists would be required, and Lum set about recruiting professors, graduate students and industrial chemists from universities and laboratories in the area. The first of these recruits commenced in August 1943, but few had any experience with
radiochemistry
Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to ...
. Numbers increased from 46 full-time employees at the end of 1943 to 101 at the end of 1944, 201 at the end of 1945, and 334 at the end of 1946, including 34 members of the Army's
Special Engineer Detachment The Special Engineer Detachment (SED) was a US Army program that identified enlisted personnel with technical skills, such as machining, or who had some science education beyond high school. Those identified were organized into the Special Engineer ...
.
Locations
Office space was initially found in the Monsanto offices at 1515 Nicholas Rd, which became known as Unit I.
Unit II was the Monsanto Rocket Propellant works off Betty Lane near
Ohio State Route 741
State Route 741 (SR 741) is a north–south state highway in the southwest portion of the U.S. state of Ohio. The southern terminus of the route is at a diamond interchange with Interstate 71 in Ohio, I-71 at its Exit 25 near Kings Mills, ...
. While it was administered by Monsanto, it was not used by the Dayton Project. The site handled explosives including
ammonium nitrate
Ammonium nitrate is a chemical compound with the chemical formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is ...
and
ammonium picrate
Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed in 1906 by US Army Major Beverly W. Dunn, who later served as the chief inspector of the Bureau of Transportation Explosives. Ammonium picrate is ...
, but no radioactive materials were handled there. Work at Unit II ceased in the fall of 1945. Consideration was given to using it in December 1946, but this proposal was rejected in favor of erecting a
Quonset hut
A Quonset hut is a lightweight prefabricated structure of corrugated galvanized steel having a semi cylindrical cross-section. The design was developed in the United States, based on the Nissen hut introduced by the British during World War I ...
at Unit III.
A laboratory site was found at 1601 W. First Street that had originally been constructed to house the
Bonebrake Seminary. It was a three-story brick building built in 1879, and owned by the Dayton Board of Education, which used it as a warehouse. Monsanto leased the site on 15 October 1943, and began converting it into a laboratory known as Unit III. The building was in poor shape when the Dayton Project took it over, with many broken windows, and the staircase between the second and third floors was missing. New heating and lighting were installed, windows were replaced, new flooring was laid, and some rooms were re-plastered. A pair of guard houses known as buildings J and K were added, as was a chemical storage shed known as building F, and a wire fence. Laboratory activities were transferred there from Unit I on 25 September. Initially only the bottom two floors were occupied, providing of laboratory space. Later, the third floor was taken over as well, providing another .
In May 1945, five additional temporary buildings were constructed on land leased from the Board of Education that housed offices, a cafeteria, locker rooms, a physics laboratory and a laundry. A new guardhouse was also built. To this was added two portable buildings in 1946.
![Dayton Project - Unit IV in October 1947](https://upload.wikimedia.org/wikipedia/commons/6/62/Dayton_Project_-_Unit_IV_in_October_1947.jpg)
By 1944, space was running short, and Monsanto began negotiations to acquire the Runnymede Playhouse in the wealthy residential Dayton suburb of
Oakwood. Built in 1927, the Playhouse was a leisure facility that included an outdoor swimming pool, a ballroom, a squash court, a tennis court with a cork floor and a stage for community theater. It had showers with Italian marble and a -story garage.
The estate was owned by the Talbott Realty Company, which was controlled by Thomas's
wife's family. The Talbotts were among the heirs of the
Delco company, which was by then a part of
General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
.
The Oakwood City Council wanted the Playhouse as a community center. Thomas appeared before the council and assured them that it would not be damaged, although he could not disclose what he was intending to use it for.
When Talbott Realty proved reluctant to sell, the
condemned
Condemned or The Condemned may refer to:
Legal
* Persons awaiting execution
* A condemned property, or condemned building, by a local authority, usually for public health or safety reasons
* A condemned property seized by power of eminent domain
...
the property, which became Unit IV on 15 February 1944. A lease was signed on 10 March 1944, under which the Talbott Realty was paid $4,266.72 per annum for the property. The lease was initially up to 30 June 1944, but was then extended annually until 30 June 1949. The lease specified that the property would be returned in its original condition. Talbott Realty were told that the property would be used to produce training films.
![Dayton Project - Unit III in October 1947](https://upload.wikimedia.org/wikipedia/commons/b/bb/Dayton_Project_-_Unit_III_in_October_1947.jpg)
Remodeling began on 17 March 1944. The tennis courts were subdivided into multiple rooms. The ceiling was lowered, and heating, air conditioning and air filtration systems were added. One of the greenhouses was converted into a
loading dock
A loading dock or loading bay is an area of a building where goods vehicles (usually road or rail) are loaded and unloaded. They are commonly found on commercial and industrial buildings, and warehouses in particular. Loading docks may be exterio ...
. The property was enclosed in a barbed wire fence that was floodlit by night, and patrolled around the clock by armed guards; there were 43 guards at Units III and IV. The Production Group began moving in on 1 June. Three guard houses were added, along with a wire fence. Changes to the site were minimized in order to make it easier to restore later. Because it was located in a residential area, efforts were also made to minimize noise and other disruptions.
In May 1945, Monsanto rented three floors of a warehouse at 601 East Third Street from
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
. Initially it was used to receive and store equipment used by the Project. Later the fourth floor was used as office space, and a laboratory was established on the fifth floor where studies were carried out on the effects of polonium on laboratory animals. Analysis of
bioassay
A bioassay is an analytical method to determine the concentration or potency of a substance by its effect on living animals or plants (''in vivo''), or on living cells or tissues(''in vitro''). A bioassay can be either quantal or quantitative, dir ...
samples was carried out there to minimize the danger of polonium contamination of the samples.
Research
Few people had seen polonium before. It was a silvery metal. In a dark room, it gave off an eerie, purple glow. Polonium occurs naturally in various ores, and the
lead dioxide
Lead(IV) oxide is the inorganic compound with the formula PbO2. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applicatio ...
residues from the refinery in
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. ...
, left over after the removal of
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 ...
and radium, were estimated to contain of polonium per metric ton. A
curie
In computing, a CURIE (or ''Compact URI'') defines a generic, abbreviated syntax for expressing Uniform Resource Identifiers (URIs). It is an abbreviated URI expressed in a compact syntax, and may be found in both XML and non-XML grammars. A CURIE ...
of polonium weighs about . Port Hope was already under contract from the Manhattan Project for the supply and refining of uranium ore. The first of radioactive lead dioxide was delivered to the Dayton Project on 10 November 1943. The first batch was processed by 8 December, which made of polonium available for experiments a week later.
Three processes were investigated for extracting the polonium from the ore. J. H. Dillon of the
Firestone Tire and Rubber Company
Firestone Tire and Rubber Company is a tire company founded by Harvey Firestone (1868–1938) in 1900 initially to supply solid rubber side-wire tires for fire apparatus, and later, pneumatic tires for wagons, buggies, and other forms of wheeled ...
had patented a process in which the lead oxide was dissolved in
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
:
: + 4 HCl → + + 2
The polonium could then be deposited on
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 ...
or
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
sheets. This required large-scale glass-lined equipment not available in Dayton, but available at the Monsanto B plant in
Monsanto, Illinois. After small-scale tests at Unit III revealed that the process was practical, some three tons of lead dioxide were sent to the B plant, and were recovered. Getting the polonium off the copper and nickel sheets proved more problematic.
A second method attempted was a kiln process. The idea was to simply roast the lead dioxide and vaporize the polonium. The problem was that lead dioxide slagged at , which was too low for the process to work. So
lead orthophosphate was tried, which slagged at . This was made by mixing the lead dioxide with
phosphoric acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...
. Experiments showed that the polonium vaporized well when the lead orthophosphate was heated to for four hours. Unfortunately, the process then ran into problems with dust and other foreign matter, and with contamination of the personnel and equipment involved.
The third method involved dissolving the lead dioxide in a mixture of concentrated
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...
and
hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
:
: + 2 + → + + 2
This proved to be the best way to separate the polonium from the lead dioxide, although there were problems with the precipitation of various contaminants, including
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
and
aluminum
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
. Although about of lead dioxide were treated with nitric acid, and about of polonium were produced, the process did not proceed beyond the pilot stage because a better source of polonium became available. The lead dioxide was not purchased by the Manhattan Project, and early in the war had been acquired by the Canadian government. In June 1945, the lead was precipitated as a
lead carbonate
Lead(II) carbonate is the chemical compound with the chemical formula . It is a white solid with several practical uses, despite its toxicity. It occurs naturally as the mineral cerussite.
Structure
Like all metal carbonates, lead(II) carbonate a ...
slurry, and shipped to the Manhattan District's Madison Square area to be dried and returned to Canada.
Production
Polonium could also be produced by neutron irradiation of
bismuth
Bismuth is a chemical element with the Symbol (chemistry), 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 ...
. In 1943 the only polonium produced in this manner was in
cyclotron
A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Janu ...
s, but the Manhattan Project's development of
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 from nu ...
s offered the prospect of producing large amounts of polonium in this manner:
: + → → +
A metric ton of bismuth irradiated in the Manhattan Project's
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 plutoni ...
in
Oak Ridge, Tennessee
Oak Ridge is a city in Anderson and Roane counties in the eastern part of the U.S. state of Tennessee, about west of downtown Knoxville. Oak Ridge's population was 31,402 at the 2020 census. It is part of the Knoxville Metropolitan Area. Oak ...
, contained of polonium, a vast improvement over the yields from Port Hope's lead dioxide. Irradiated bismuth came from Clinton in the form of bricks that weighed about . They were shipped to Dayton by rail in wooden boxes, which were stored in a tile-lined cavity in the floor at Unit IV.
These procedures were adequate because the quantity of polonium in the bismuth was still fairly low, but starting in June 1945, the Dayton Project began receiving bismuth irradiated in the more powerful reactors at 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 ...
in Washington, which now became the major source of supply. Even at Clinton, unprotected bismuth proved problematic when a brick broke apart and chips fell into containers of uranium slugs, and had to be hazardously separated by hand by project personnel. Bismuth slugs irradiated in the reactors at Hanford were therefore canned in aluminium. The canned slugs were in diameter, and long. The problem was that the aluminium contained impurities such as
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
,
manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
,
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 ...
, lead,
tin
Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal.
Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...
,
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
,
silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
,
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
,
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
,
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
,
chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
,
vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...
, bismuth and
gallium
Gallium is a chemical element with the symbol Ga and atomic number 31. Discovered by French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in group 13 of the periodic table and is similar to the other metals of the group (aluminiu ...
, and when irradiated, these could form radioactive isotopes. Most were of little concern for the Dayton Project, as they had short half-lives, and would become harmless during the slugs' cooling off period in water at Hanford; but iron could form iron-59, which had a half-life of 45 days, and produced gamma radiation. The slugs were therefore shipped in casks, each of which contained several tubes which held the slugs. The spaces between the tubs was filled with lead. At Dayton, the slugs were stored in a lead-lined safe with doors on both sides containing tubes. They were also stored underwater on racks, and could be removed with tongs. A periscope allowed the identification markings on the slugs to be checked without removing them from the pool.
By the end of 1946 Hanford was shipping material that contained up to per metric ton of bismuth. Bismuth was purchased from the
American Smelting and Refining Company
Asarco LLC (American Smelting and Refining Company) is a mining, smelting, and refining company based in Tucson, Arizona, which mines and processes primarily copper. The company has been a subsidiary of Grupo México since 1999.
Its three large ...
of the highest purity that it could produce. It was sent to Hanford, where it was canned, and placed inside a reactor for 100 days. The irradiated slugs were then shipped by road to Unit IV, where they were bathed in hydrochloric acid, which dissolved the aluminum. This formed an aluminum chloride solution that was disposed of, as it was highly radioactive due to the iron impurities in the aluminum. The bismuth slugs were then dissolved in
aqua regia. This was too weak for electroplating the polonium, so the nitric acid was removed, and then the polonium deposited on bismuth by adding powdered bismuth. This resulted in a 100–1 concentration. This could then be repeated by dissolving in aqua regia again to achieve a 1000–1 concentration. This was again dissolved, and the polonium electroplated on
platinum
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver".
Platinu ...
foils. The main problem with the process was that it required glass-lined containers due to the aqua regia, and mechanisms for safe handling of the radioactive material. The Dayton Project explored alternative purification methods that were found to be workable, but less efficient or safe.
The first consignment of polonium left for Los Alamos on 15 March 1944 in a lead-lined suitcase carried by a military courier. Regular shipments were made thereafter.
Initiator testing at Los Alamos required more polonium than anticipated, and in December 1944, Oppenheimer was forced to ask Thomas if he could ship per month. The Dayton Project was able to do so. In February 1945, Thomas agreed to increase shipments to per month by June, and 500 per month by December.
The total cost of the Dayton Project up to the end of 1946 was $3,666,507 ($ in today's dollars).
Health and safety
Dayton Project employees were not allowed to eat or smoke in processing areas, and had to scrub their hands before leaving these areas. The chemists wore protective gear, with surgical, cloth and rubber gloves worn in three layers. When leaving for lunch or at the end of the shift, they had to wash their hands with dilute hydrochloric acid, dilute
Clorox
The Clorox Company (formerly Clorox Chemical Company) is an American global manufacturer and marketer of consumer and professional products. As of 2020 the Oakland, California based company had approximately 8,800 employees worldwide. Net sales ...
, and soap. The radioactive residue on their hands was measured with a special
Geiger counter
A Geiger counter (also known as a Geiger–Müller counter) is an electronic instrument used for detecting and measuring ionizing radiation. It is widely used in applications such as radiation dosimetry, radiological protection, experimental ph ...
designed for the purpose by physicist John J. Sopka.
No more than one thousand counts per minute per hand was permissible. They had to shower at the end of each day's work, and were subjected to weekly urine tests. Employees with elevated levels of polonium were not allowed in the processing areas. Working with polonium without spreading contamination proved to be almost impossible. Fortunately, it is not a
bone seeker A bone seeker is an element, often a radioisotope, that tends to accumulate in the bones of humans and other animals when it is introduced into the body. An example is strontium-90, which behaves chemically like calcium and can replace the calcium ...
like radium or plutonium, and is thus readily excreted in urine. Detection methods had already been developed, making it easy to track. The employee at Unit IV with the highest levels of polonium in her urine had contaminated her hair, and often held
bobby pin
A bobby pin (also known as a kirby grip or hair grip in the United Kingdom) is a type of hairpin, usually of metal or plastic, used in coiffure to hold hair in place. It is a small double-pronged hair pin or clip that slides into hair with the pr ...
s in her mouth.
Espionage
George Koval
George Abramovich Koval ( rus, Жорж (Георгий) Абрамович Коваль, p=ˈʐorʐ (ɡʲɪˈorɡʲɪj) ɐˈbraməvʲɪtɕ kɐˈvalʲ, a=Ru-George Abramovich Koval.flac, Zhorzh Abramovich Koval; December 25, 1913 – January 31 ...
was drafted into the United States Army in 1943, and was inducted into the Manhattan Project's Special Engineer Detachment. He was initially assigned to the Clinton Engineer Works, where his job as a
health physics
Health physics, also referred to as the science of radiation protection, is the profession devoted to protecting people and their environment from potential radiation hazards, while making it possible to enjoy the beneficial uses of radiation. He ...
officer gave him access to much of the site. He began passing secrets relating to the production of polonium at Oak Ridge to the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
through his
GRU
The Main Directorate of the General Staff of the Armed Forces of the Russian Federation, rus, Гла́вное управле́ние Генера́льного шта́ба Вооружённых сил Росси́йской Федера́ци ...
(Soviet military intelligence) handler code-named "Clyde". In 1945 Koval was transferred to Dayton. Again, his job as a health physics officer gave him wide access to the secret installation.
In 2007 Russian President
Vladimir Putin
Vladimir Vladimirovich Putin; (born 7 October 1952) is a Russian politician and former intelligence officer who holds the office of president of Russia. Putin has served continuously as president or prime minister since 1999: as prime min ...
posthumously awarded Koval a gold star, making him a
hero of the Russian Federation
Hero of the Russian Federation (russian: Герой Российской Федерации, Geroy Rossiyskoy Federatsii), also unofficially Hero of Russia (russian: link=no, Герой России, Geroy Rossii), is the highest honorary title ...
for his work as the GRU spy "Delmar". Russian officials stated that the initiator for their
Joe-1
The RDS-1 (russian: РДС-1), also known as Izdeliye 501 (device 501) and First Lightning (), was the nuclear bomb used in the Soviet Union's first nuclear weapon test. The United States assigned it the code-name Joe-1, in reference to Joseph S ...
bomb had been "prepared to the recipe provided by Delmar".
The fact that polonium was used as an initiator remained classified until the 1960s.
Initiators
After
Leonard I. Schiff Leonard Isaac Schiff was born in Fall River, Massachusetts on March 29, 1915
and died on January 21, 1971 in Stanford, California.
He was a physicist best known for his book ''Quantum Mechanics'', originally published in 1949 (a second edition appe ...
calculated that an initiator could theoretically improve the efficiency of a
gun-type fission weapon
Gun-type fission weapons are fission-based nuclear weapons whose design assembles their fissile material into a supercritical mass by the use of the "gun" method: shooting one piece of sub-critical material into another. Although this is sometim ...
, Oppenheimer gave approval on 15 March 1945 for initiators to be included in the
Little Boy
"Little Boy" was the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress ''Enola Gay'' p ...
design. Testing was carried out to ensure that the initiators were rugged enough to handle being transported in an airplane and being accidentally dropped. Eventually, about forty initiators were despatched to
Tinian
Tinian ( or ; old Japanese name: 天仁安島, ''Tenian-shima'') is one of the three principal islands of the Commonwealth of the Northern Mariana Islands. Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of th ...
, where four were inserted into the bomb that was used in the bombing of Hiroshima.
The initiator used in the
implosion design of the
Fat Man
"Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the fir ...
bomb that was dropped on
Nagasaki
is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan.
It became the sole port used for trade with the Portuguese and Dutch during the 16th through 19th centuries. The Hidden Christian Sites in the ...
was code-named "urchin". In order to increase the efficiency of the explosion, the initiator had to emit a large number of neutrons in a few microseconds while the plutonium
core
Core or cores may refer to:
Science and technology
* Core (anatomy), everything except the appendages
* Core (manufacturing), used in casting and molding
* Core (optical fiber), the signal-carrying portion of an optical fiber
* Core, the central ...
was fully compressed. At the heart of the urchin was a solid beryllium sphere in diameter. This was
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
-plated and coated with of polonium. The gold kept the polonium's
alpha particle
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produce ...
s from striking the beryllium. This fitted inside two beryllium hemispheres with 15 parallel grooves cut into the inner surface. These grooves converted the shock wave of the implosion into
jets that shattered the spheres and caused the beryllium and polonium to mix and emit neutrons. The hemispheres were nickel-plated and the outer surface was coated in gold and of polonium. The initiator, which was hot to the touch, fitted neatly inside the hole in the center of the plutonium pit.
Mound Laboratories
![Department of Energy - Mound Plant - Electronics Laboratory Building](https://upload.wikimedia.org/wikipedia/commons/6/68/Department_of_Energy_-_Mound_Plant_-_Electronics_Laboratory_Building.jpg)
By 1945, the Dayton Project has assumed such importance that the Manhattan Project decided to make it into a permanent facility. The original intention was to move operations to Oak Ridge, but it was decided that a site near Dayton was preferable. Few of the scientific and technical staff wanted to move to Tennessee, and there were concerns about the dangers of polonium contamination at a plutonium processing site. A search for a suitable site began in early 1946, and one was found in Miamisburg, about from Dayton. The site was adjacent to a state park containing a large prehistoric Indian
burial mound
Burial, also known as interment or inhumation, is a method of final disposition whereby a dead body is placed into the ground, sometimes with objects. This is usually accomplished by excavating a pit or trench, placing the deceased and objec ...
, which ultimately gave the
Mound Laboratories
Mound Laboratory in Miamisburg, Ohio was an Atomic Energy Commission (later Department of Energy) facility for nuclear weapon research during the Cold War, named after the nearby Miamisburg Indian Mound.
The laboratory grew out of the World War ...
their name. It was initially known as Unit V. Monsanto commenced construction in May 1946, using the firm of Giffels and Vallet of Detroit as architects, while the plant was built by the Maxon Construction of Dayton. The design called for an underground complex that could withstand a direct hit from a bomb, with protection against
biological
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary in ...
and
chemical weapon
A chemical weapon (CW) is a specialized munition that uses chemicals formulated to inflict death or harm on humans. According to the Organisation for the Prohibition of Chemical Weapons (OPCW), this can be any chemical compound intended as a ...
s, at a cost of $17,900,000.
Responsibility for nuclear weapons production was transferred from the Manhattan Project to the
Atomic Energy Commission in 1947, but work continued on the Mound Laboratories. The first building was completed in May 1948, and polonium processing commenced at the Mound Laboratories in February 1949. Altogether, 14 major buildings were constructed with a total floor space of at a cost of $25.5 million. Due to fear of attack or sabotage, the former Scioto Laboratory Complex in
Marion, Ohio
Marion is a city in and the county seat of Marion County, Ohio, Marion County, Ohio, United States. The municipality is located in north-central Ohio, approximately north of Columbus, Ohio, Columbus.
The population was 35,999 at the 2020 United S ...
, was acquired by the Atomic Energy Commission in 1948. It was maintained as a cold standby site until it was no longer needed in 1953.
Site cleanup
Unit I continued to be used by Monsanto as an administrative facility until 1988, when it was demolished. The land was sold to Quality Chemicals in 1992, and then to DuPont in 2002. Unit III, the former Bonebrake Theological Seminary, was decontaminated in 1950 and returned to the Dayton Board of Education. The original seminary building was subsequently demolished, but several structures remain from the Dayton Project. The site was listed on the
National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic v ...
on 10 May 2006. Although the lease on Unit IV, the former Runnymede Playhouse, specified that it was to be returned, it was deemed to be too contaminated. The building was demolished in February 1950. The cobblestones in the driveway were removed and taken away, along with of earth from under the house. The excavation was filled in, and the site was returned to the Talbott family, who were paid $138,750 in compensation. , all that remains of the original playhouse is a brass doorknob and part of the greenhouse roof, which are part of the collection of the Mound Science and Energy Museum. Private residences now occupy the site.
The Dayton Warehouse was decontaminated in 1950 and returned to its owners. The Mound Laboratories continued to produce polonium initiators until 1969. Polonium continued to be produced there for commercial sales and use in satellites until 1972. The laboratories were decommissioned in 1993, and the area was decontaminated. , it houses the Mound Advanced Technology Center.
In 1996, the
Department of Energy A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-rel ...
, which had succeeded the Atomic Energy Commission, decided that since the Dayton sites already had been decontaminated, they did not warrant inclusion in the Army Corps of Engineers'
Formerly Utilized Sites Remedial Action Program The Formerly Utilized Sites Remedial Action Program (FUSRAP) is a United States Army Corps of Engineers (USACE) project to manage and cleanup environmental contamination that resulted from early United States Atomic Energy Commission activities. Cl ...
(FUSRAP). The local community in Dayton was concerned that the cleanup did not meet 21st century environmental standards. Therefore, the state of Ohio asked the
United States Congress
The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washing ...
to have the Army Corps of Engineers conduct a review. This was carried out in 2004 and 2005. The review concluded that no radioactive contaminants were found that would warrant inclusion in FUSRAP.
Notes
References
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