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uranium

(Encyclopedia)uranium yo͞orāˈnēəm, radioactive metallic chemical element; symbol U; at. no. 92; mass number of most stable isotope 238; m.p. 1,132℃; b.p. 3,818℃; sp. gr. 19.1 at 25℃; valence +3, +4, +5, ...

Uranium City

(Encyclopedia)Uranium City, town, NW Sask., Canada, on Lake Athabasca near the Northwest Territories line. A large uranium-mining area from the 1950s, the closure of its mines in 1982 has led to economic collapse. ...

pitchblende

(Encyclopedia)pitchblende pĭchˈblĕndˌ [key], dark, lustrous, heavy mineral, a source of radium and uranium. Largely natural uranium oxides, triuranium octaoxide (U3O8) and uranium dioxide (UO2), it usually cont...

Manhattan Project

(Encyclopedia)Manhattan Project, the wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materi...

Elliot Lake

(Encyclopedia)Elliot Lake, city, S central Ont., Canada, W of Sudbury. The focus of a 1950s uranium-mining boom, it is now a retirement home center. Uranium mining en...

Blind River

(Encyclopedia)Blind River, town, S Ont., Canada, on North Channel of Lake Huron. It is the center of the Algoma uranium fields. Just to the east of the town is Ontari...

plutonium

(Encyclopedia)plutonium plo͞otōˈnēəm [key], radioactive chemical element; symbol Pu; at. no. 94; mass no. of most stable isotope 244; m.p. 641℃; b.p. 3,232℃; sp. gr. 19.84 at 20℃; valence +3, +4, +5, or ...

centrifuge

(Encyclopedia)centrifuge sĕnˈtrəfyo͞oj [key], device using centrifugal force to separate two or more substances of different density, e.g., two liquids or a liquid and a solid. The centrifuge consists of a fixe...

actinium series

(Encyclopedia)actinium series, natural radioactive decay series beginning with uranium-235 (also called actinouranium) and ending with lead-207. See radioactivity. ...

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