On December 2, 1942, the world's first artificial self-sustaining nuclear chain reaction took place in the world's first nuclear reactor, Chicago Pile Number One, shortened as CP-1, built on a racquets court under the abandoned west stands of the Alonzo Stagg Field stadium on the University of Chicago campus. Operation of CP-1 was terminated in February 1943 and the nuclear reactor dismantled and moved to the laboratory's Palos Park site A. It was reconstructed using CP-1 materials but enlarged with a radiation shield and named CP-2. It began operation in March 1943. December 2 is the 336th day (337th in leap years) of the year in the Gregorian calendar. ... This article is about the year. ... Albert Einsteins letter to President Roosevelt in 1939 about his concern, about (Nuclear chain reactions) Click for closeup of letter A nuclear chain reaction occurs when on average more than one nuclear reaction is caused by another nuclear reaction, thus leading to an exponential increase in the number of... Core of a small nuclear reactor used for research. ... R. P. Keigwin (right) with AEJ Collins the Colleges racquets team at Clifton College circa 1902 Racquets (American English) or rackets (British English) is an indoor racquet sport played in the United Kingdom, United States, and Canada. ... Stagg Field was a stadium in Chicago, Illinois. ... The University of Chicago is a private university located principally in the Hyde Park neighborhood of Chicago, Illinois. ... The Universitätscampus Wien, Austria ( details) Campus (plural: campi) is Latin for field or open space. English gets the words camp and campus from this origin. ... 1943 (MCMXLIII) was a common year starting on Friday (the link is to a full 1943 calendar). ... Palos Park is a village located in Cook County, Illinois. ... Radiation protection, sometimes known as radiological protection, is the science of protecting people and the environment from the harmful effects of radiation. ... 1943 (MCMXLIII) was a common year starting on Friday (the link is to a full 1943 calendar). ...

The reactor was a pile of uranium and graphite blocks, assembled under the supervision of the renowned Italian physicist Enrico Fermi. It contained critical mass of the fissile material, together with control rods, and was built as a part of Manhattan Project research done by the University of Chicago Metallurgical Laboratory. The shape of the pile was intended to be roughly spherical, but as work proceeded, Fermi calculated that critical mass could be achieved without finishing the entire pile as planned. General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... Enrico Fermi in the 1940s Enrico Fermi (September 29, 1901–November 28, 1954) was an Italian physicist most noted for his work on beta decay, the development of the first nuclear reactor, and for the development of quantum theory. ... A sphere of plutonium surrounded by neutron-reflecting blocks of tungsten carbide. ... A control rod is a rod made of a chemical element capable of absorbing many neutrons without decaying themselves. ... The Manhattan Project resulted in the development of the first nuclear weapons, and the first-ever nuclear detonation at the Trinity test of July 16, 1945. ... This sculpture by Henry Moore marks the site at the University of Chicago where Metallurgical Laboratory scientists created the worlds first self-sustaining nuclear chain reaction. ...

A labor strike prevented the construction of the pile at a laboratory in the Argonne forest preserve, so Fermi and his associates Martin Whittaker and Walter Zinn set about building the pile (the world's first "nuclear reactor," although that term was not used until 1952) in a racquets court under the abandoned west stands of the university’s Stagg Field. The pile consisted of uranium pellets as a neutron–producing "core" separated from one another by graphite blocks to slow the neutrons. Fermi himself described the apparatus as "a crude pile of black bricks and wooden timbers." The controls consisted of cadmium-coated rods that absorbed neutrons. Withdrawing the rods would increase neutron activity in the pile to lead to a self-sustaining chain reaction. Re-inserting the rods would dampen the reaction. Argonne National Laboratory is one of the United States governments oldest and largest science and engineering research national laboratories and is the largest in the Midwest. ... 1952 (MCMLII) was a Leap year starting on Tuesday (link will take you to calendar). ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... In nuclear engineering, a neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Atomic mass 112. ...

On December 2, 1942, Chicago Pile 1 (CP-1) was ready for a demonstration. Before a group of dignitaries, a young scientist named George Weil worked the final control rod while Fermi carefully monitored the neutron activity. The pile went critical at 3:20 p.m. Fermi shut it down 33 minutes later. In 1943, he rebuilt the pile as CP-2 at the Argonne Laboratory. December 2 is the 336th day (337th in leap years) of the year in the Gregorian calendar. ... This article is about the year. ... San Francisco Critical Mass, 29th April, 2005. ...

A small graphite block from the pile is on display at the Museum of Science and Industry in Chicago. The Museum of Science and Industry is housed in the only surviving building from the 1893 World Columbian Exposition and is a National Historic Landmark. ...

See also

• SCRAM

A SCRAM is an emergency shutdown of a nuclear reactor - though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads (see Tech Model Railroad Club). ...

References

Fermi E (1946). "The Development of the first chain reaction pile". Proceedings of the American Philosophy Society 90: 20-24. tif]

Illustrations (external site)

• Drawing of the first atomic pile Artist drawing of CP-1

• AtomicArchive.com Photographs from assembling the pile

External links

• The Story of the First Pile