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Building 996

Rocky Flats Plant, Storage Vault
HAER No. CO-83-E (Rocky Flats Plant, Building 996)

Note: The documentation for Building 996 also represents other storage vaults, including Buildings 997, 998, and 999.

Rocky Flats Environmental Technology Site, Highway 93, Golden, Jefferson County, Colorado. Building 996 is in the southeast corner of the protected area, northwest of Building 991.

This building is a primary contributor to the Rocky Flats Plant historic district, associated with the U.S. strategy of nuclear military deterrence during the Cold War, a strategy considered of major importance in preventing Soviet nuclear attack. Building 996, part of the original Plant D (Building 991) was used to store nuclear weapons components awaiting off-site shipment. The storage vaults at the Rocky Flats Plant are unique in construction. The walls of the vaults are constructed of reinforced concrete approximately 14.5 feet in thickness and are buried 15 feet underground. At other Department of Energy weapons production facilities, storage vault walls are generally constructed only 2- to 3-feet-thick.

Building 996 is an underground vault, rectangular in shape. The vault is 60 by 68 feet and 10 feet high. Heavy walls divide the vault into five, nearly equal, rooms and an entry hall. A 6-inch-thick metal door seals the vault. The underground vault is constructed of thick, reinforced concrete. Air is supplied to the vault through an air supply plenum, and air is exhausted through the air filter plenum in Building 985.

Building 996 is located northwest of Building 991, and is connected to the northwest corner of the building by underground Tunnel 996. Tunnel 996 is 10 to 12 feet wide by 11 to 13 feet high and approximately 25 yards long. At the northwest end of Tunnel 996, Tunnel 997 begins and proceeds west for approximately 100 yards, a distance often traveled by employees on bicycles (Cunningham). Building 997 is at the western-most end of Tunnel 997, and Building 999 is on the north side approximately midway along Tunnel 997. Building 997 is a four-room chamber, similar in design and size to Building 996. Building 999 is a three-room chamber.

A second tunnel/vault system (Tunnel 998) extends from the center of the north wall of Building 991. Tunnel 998 is 7.5 feet wide and 10 feet high. Vault 998 is a one-room vault. The four vaults have a total area of 20,940 square feet.

Building 996 was constructed in 1952 as part of the original Plant D, Building 991. Building 991 was the shipping and receiving facility for incoming and outgoing special nuclear material and supplies. Trigger components manufactured in other buildings around the plant, as well as components manufactured at the Oak Ridge Tennessee facility, were sent to Plant D for assembly and storage. The Rocky Flats Plant received and shipped products by rail and by truck. The assembled triggers (also known as pits) were shipped off site to the Pantex Plant in Amarillo, Texas, for final weapons assembly. A railroad spur terminated to the northeast of Building 551 near the center of the industrial area of the site. For each off-site rail shipment, members of the heavily armed protective force (site security personnel) would escort the shipment from the vault, across the site, and on to the boxcars waiting at the railroad spur (Richmond).

Retired triggers were also sent back to the Rocky Flats Plant from Pantex for recovery of valuable plutonium and uranium. The retired triggers were stored in the underground vaults until they were moved to the 700-Area Complex where recovery operations took place.

Building 999 was constructed in 1959 to increase storage capacity. For security reasons, the contractor hired to construct the vault was not allowed access from or contact with Tunnel 997. After the contractor completed the vault, site personnel cut a hole in the tunnel wall and connected Building 999 to the tunnel.

Cunningham, Steve, employed at the plant since 1977 by the site contractor. Personnel communication, August 1997.

Richmond, Lou, employed at the plant since 1970 by the site contractor. Personnel communication,
August 1997.

U.S. Department of Energy. Historical Release Report (HRR) (1994), by EG&G. Rocky Flats Plant Repository.
Golden, Colorado, 1994.

U.S. Department of Energy. Site Safety Analysis Report, Notebook 13-Security (1995), by EG&G Rocky Flats, Inc.
Rocky Flats Plant Repository. Golden, Colorado, 1995.

U.S. Department of Energy. Final Cultural Resources Survey Report (1995), by Science Applications International Corporation. Rocky Flats Repository. Golden, Colorado, 1995.

Wilson, Sharon, employed at the plant since 1981 by the site contractor, personal communication,
September 1997.

D. Jayne Aaron, Environmental Designer, engineering-environmental Management, Inc. (e2M), 1997. Judith Berryman, Ph.D., Archaeologist, e2M, 1997.

Index to Photographs

Located in the southeast corner of the protected area, northwest of Building 991, Golden Vicinity, Jefferson County, Colorado.

Photograph from the Rocky Flats Plant photography archives, site photography contractor, summer 1994.

CO-83-E-1 – View of one of the inner rooms within Vault 996. The underground vaults were used to store special nuclear material awaiting on- and off-site shipment.