February 2014 Columbia Section Meeting – 618-10 Vertical Pipe Unit Retrieval Design

This month we welcome Kim Koegler with Washington Closure Hanford to O’Callahan’s in the Shilo Inn at Richland.

Washington Closure Hanford, as the contractor to the U.S. Department of Energy on the River Corridor Closure Contract, is charged with the remediation of Vertical Pipe Units at the 618-10 and 618-11 Burial Grounds. VPUs were one of the methods used for waste disposal at Hanford Site during the 1960’s. The first generation of VPUs was simply pipes, 10- to 12-in diameter and 10- to 15-ft long, buried vertically. The second generation of VPUs was 22-in diameter, 15-ft long waste receptacles constructed by welding five 55-gallon bottomless drums together end-to-end and burying them vertically, separated by approximately 10 feet on center. The 618-10 Burial Ground contains approximately 94 VPUs (uncertain mix of first and second generation). The 618-11 Burial Ground contains 50 VPUs (all second generation).

The 618-10 and -11 Burial Grounds received low- to high-activity waste (e.g., fission products and some plutonium-contaminated waste). Most of the waste originated at the 300 Area laboratory facilities. Historical documents indicate that shielding materials (i.e., concrete and soil) were added to the VPUs, as necessary, to reduce dose rates over the openings.  Historical documents also indicate that the VPUs were backfilled with sand and capped with concrete after the VPUs stopped receiving waste, and were covered with approximately 2-ft of soil when they were closed.  An additional 2-ft of topsoil was later added to each site for surface stabilization.

A design for VPU remediation has been developed and is being refined through full-scale mockup methods testing. This presentation will provide an overview of the VPU challenges and the remediation design.

Register here:  http://events.constantcontact.com/register/event?llr=tpugxclab&oeidk=a07e8skna9gab29fef9