Columbia Energy produced a conceptual design report providing the technical basis and strategy for landfill closure of the 241-C Waste Management Area (WMA C) located at the Hanford Site north of Richland, Washington.  The conceptual design report describes the design concepts for landfill closure including the approach for stabilizing residual waste remaining in the tanks, grout filling the below grade structures and equipment to prevent long-term subsidence, covering WMA C with a closure cap (engineered surface barrier) to isolate contamination, and constructing a monitoring system for long-term monitoring of the waste area following completion of closure.

A series of Value Engineer (VE) sessions were held to identify, evaluate, and select approaches to implement different portions of the closure scope.  The closure design addressed all below grade and above grade structures including: 16 single-shell tanks, 7 diversion boxes, 1 catch tank, CR vault containing 4 tanks, and numerous ancillary equipment.

Columbia Energy developed a technically sound and cost-effective engineering concept for WMA C closure that ultimately supports the regulatory requirements for single-shell tank waste retrieval and tank farm closure established in the Hanford Federal Facility and Consent Order (HFFACO), as well as closure of WMA C by June 30, 2019 per Ecology Milestone M-45-83.


  • Engineering and Design
  • Value Engineering
  • NQA-1 Oversight
  • Supporting Documentation

Design Features and Specifications

  • Grouting and Cementing of below-grade structures to prevent subsidence


  • U.S. Department of Energy (DOE)
  • U.S. Department of Ecology
  • Office of River Protection (ORP)
  • Washington River Protection Solutions (WRPS)