Reactor Decommissioning History
Omega West
revised 8/30/06

Overview

Omega West was the name for the fifth reactor in Technical Area 2 (TA-2) at Los Alamos National Laboratory (LANL). Omega West went critical in 1956 and fuel removed in 1994. It was a thermal, heterogeneous, closed tank-type test and research reactor. It was light-water moderated and cooled. The core assembly consisted of an aluminum pedestal and grid assembly inside a stainless steel tank. The tank was 8-feet (2.4-meters) diameter x 24-feet (7.3-meters) tall. Removal was completed by July 2003.

Reactor Decommissioning Specifics

Internals Removal
Remote disassembly done mechanically. Limited cutting using Plasma Arc and mechanical shears for size reduction. All done dry (not underwater).

Reactor Vessel Removal
The vessel was removed using remote tools (Track Hoe w/hammer & shear, BROKK w/hammer & shear as bioshield was demolished).

Segmentation and Packaging Plan (S&P Plan)
Plan unknown.

Key People
Stephen Mee (LANL).
Keith Rendell (LANL).
John Gallegos (NNSA).
Joe Stringer (Framatome ANP - currently AREVA NP).

Contractors
NNSA (U.S. National Nuclear Security Administration - the client)
WD3 (joint venture of Framatome ANP and Washington Group).
MOTA Corporation.

Comments
Because of a coolant leak years earlier water shielding was not available. A movable radiation shield was placed on the core lid. A vertical shield was also used to protect workers from radiation scatter.

Related Publications and Documents
"It Takes a Team" article in Radwaste Solutions, March/April 2004.
Paper presented at the French Nuclear Energy Society conference on "Decommissioning Challenges: An Industrial Reality?" held November 23-28, 2003.

References
Radwaste Solutions, March/April 2004.
MOTA Corporation web page as of 8/14/05.
Don McGee correspondence 8/21/06.

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