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
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
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
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.
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,
Wilson, Sharon, employed at the plant since 1981 by the site contractor,
D. Jayne Aaron, Environmental Designer, engineering-environmental
Management, Inc. (e2M), 1997. Judith Berryman, Ph.D., Archaeologist, e2M,
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.