Rocky Flats Plant - Building #881 (Plant B)/Building #881

Address: Rocky Flats Environmental Technology Site, Hwy. 93, Golden 80402

This three-story, 245,160 sq. ft. building built in 1952, was used in the processing and machining of enriched uranium into finished weapons components, central computing, standards lab, and record storage. It is an irregular shaped structure built into a berm. The building is underground with the exception of Building #881F, a gable-roofed portion that rises two stories. The exterior walls are reinforced concrete, as well as the foundation. The flat roof is flush with the finished grade along the north and most of the east and west walls. In April 1952, operations began and enriched uranium operations began in June 1953. Originally used to fabricate enriched uranium. At this time the United States had a duality policy for weapons production. Enriched uranium part was also being manufactured at Oak Ridge Y-12. It was the fourth building to come on line at the Rocky Flats Plant. In 1955, an "L" shaped annex to the northwest corner was added for a machining facility (IV Expansion). From 1964 to 1966 enriched uranium operations were consolidated to Y-12 as the U.S.'s policy changed to a single mission - plutonium production became the focus of operations at Rocky Flats. From 1966 to 1984, precision stainless steel parts were manufactured in this building. In 1984, stainless steel operations moved to Building #460, and research and development, analytical support, administration, and computer facilities expanded.
Quad Map/Date: Louisville, 1965 (1979)
Sec/Town/Range: S10 & 11, T2S, R70W
Elevation: c. 6000
Source: Historic Building Inventory #5JF1014.39, 1995, Colorado Historical Society

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