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Floodplain Statement of Finding for the Disposition of the Omega West Facility at Los Alamos National Laboratory, Los Alamos, NM

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Information about this document as published in the Federal Register.

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Office of Los Alamos Site Operations, National Nuclear Security Administration, Department of Energy.


Floodplain statement of finding.


This Floodplain Statement of Findings is for the disposition of the Omega West Facility from the Los Alamos Canyon floodplain at Los Alamos National Laboratory (LANL), Los Alamos, New Mexico. This Statement of Findings is prepared in accordance with 10 CFR part 1022. The Department of Energy's (DOE) National Nuclear Security Administration (NNSA), Office of Los Alamos Site Operations plans to decontaminate and demolish the Omega West Facility from the Los Alamos Canyon bottom to reduce the potential for radioactive contaminant spread and debris dissemination in the event of a major flood. The Omega West Facility (the Facility) housed an old research reactor known as the Omega West Reactor (OWR). The OWR was shut down in 1992 and the fuel rods were removed from the Facility in 1994. The Facility, originally constructed in 1944, and its associated structures are of advanced age and not in a condition suitable for renovation or reapplication. Further, they are located within a potential flood pathway. There is no foreseeable future use for the Facility, which is eligible for inclusion in the National Register of Historic Places. NNSA prepared a floodplain assessment describing the effects, and measures designed to avoid or minimize potential harm to or within the affected floodplains.

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Elizabeth Withers, U. S. Department of Energy, National Nuclear Security Administration, Los Alamos Site Operations Office, 528 35th Street, Los Alamos NM 87544. Telephone (505) 667-8690, or facsimile (505) 667-9998; or electronic address: For Further Information on General DOE Floodplain Environmental Review Requirements, Contact: Carol M. Borgstrom, Director, Office of NEPA Policy and Compliance (EH-42), U.S. Department of Energy, 1000 Independence Avenue, SW., Washington, DC 20585-0119, Telephone (202) 586-4600 or (800) 472-2756; facsimile (202) 586-7031.

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A Notice of Floodplain Involvement was published in the Federal Register on February 20, 2002 (67 FR 7674). This Notice announced that the Floodplain Assessment would be issued together as part of the draft Environmental Assessment (EA). The draft EA was distributed to the State, Tribes, and interested parties, and was also placed in the DOE's public Reading Rooms in Los Alamos and Albuquerque, New Mexico on March 4, 2002 for a 21-day comment period. No comments were received from the Federal Register notice on the proposed floodplain action.

In May 2000, the Cerro Grande Fire burned across the upper and mid-elevation zones of several watersheds, including the Los Alamos Canyon watershed. Several of the Omega Facility's small support buildings and structures were demolished and Start Printed Page 15556disposed of during the first 6 months post Cerro Grande Fire. The remaining buildings, including Building 2-1 that houses the OWR vessel, and the associated structures and utilities and infrastructure, continue to be vulnerable to damage from flooding and mudflows as a result of the fire and the changed environmental conditions upstream from the Facility. While all buildings are vulnerable, the support buildings and structures are especially at risk due to their construction characteristics.

Project Description

NNSA proposes to decontaminate and demolish (D&D) the OWR vessel and the remaining Omega West Facility structures located within Los Alamos Canyon at Los Alamos National Laboratory, Los Alamos, New Mexico. The activities would consist of characterization and removal of radiological and other potential contamination in all the structures and subsequent demolition of the structures; dismantlement of the reactor vessel; segregation, size reduction, packaging, transportation, and disposal of wastes; and removal of several feet of potentially contaminated soil from beneath the reactor vessel; and recontouring and reseeding of the site. Decontamination of the Omega West Facility would include the removal of nonradiological and radiological contamination from building and structure surfaces throughout the Omega West Facility. The extent of decontamination performed would be limited to those activities required to minimize radiological and hazardous material exposure to workers, the public, and the environment. Once the Omega West Facility has been decontaminated, the buildings, structures, foundations, and other facility components would be demolished. All building and structural materials would be removed from the canyon and sent to appropriate disposal sites.


The draft EA considers one alternative, the Phased Removal Alternative, in addition to the Proposed Action and the No Action alternatives. Under Phased Removal Alternative, part of the Omega West Facility would be demolished in the near-term and part would be left undemolished until some point in the next 20 to 30 years. The Proposed Alternative would remove the entire Omega West Facility from the floodplain, out of the canyon, disposition the waste from the demolition, and would restore the site to a near natural condition.

Floodplain Impacts

The proposed action would benefit the floodplain. Removal of the Omega West Facility would restore floodplain values by removing obstructions to the natural flow and function of the floodplain. It would also remove a source of potential radioactive and non-radiological contamination to the downstream floodplain. Should a rain event occur during this activity, there may be some sediment movement down canyon because of the loosened condition of the soil from all the demolition and disposition.

Floodplain Mitigation

Best management practices for minimizing soil disturbance would be in place to reduce the potential for erosion. No debris would be left in the canyon bottom. There would be no vehicle maintenance or fueling within 100 feet of the stream channel. Any sediment movement from the site would be short term and temporary.

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Issued in Los Alamos, New Mexico on March 19, 2002.

Corey A. Cruz,

Acting Director, U.S. Department of Energy, National Nuclear Security Administration, Office of Los Alamos Site Operations.

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[FR Doc. 02-7923 Filed 4-1-02; 8:45 am]