Appendix A to Report of the Mixed Waste Landfill Phase 2 RCRA Facility Investigation, Sandia National Laboratories, Albuquerque, New Mexico

18 pagesThe Department of Energy/National Nuclear Security Administration (DOE) and Sandia Corporation (Sandia) have submitted a request for a Class 3 Modification to Module IV of Hazardous Waste Permit NM5890110518-1 (the Permit). DOE and Sandia are requesting that the New Mexico Environment Department (NMED) designate solid waste management unit (SWMU) 76 as approved for Corrective Action Complete status. NMED made a preliminary determination in October 2014 that corrective action is complete at this SWMU. SWMU 76, known as the Mixed Waste Landfill (MWL), is a 2.6-acre site at Sandia National Laboratories, located on Kirtland Air Force Base immediately southeast of Albuquerque, New Mexico. Radioactive wastes and mixed wastes (radioactive wastes that are also hazardous wastes) were disposed of in the MWL from March 1959 through December 1988. The maximum depth of burial is approximately 25 feet below the ground surface. Groundwater occurs approximately 500 feet below the ground surface at the MWL. From 1992 to 1995, DOE and Sandia conducted the second phase of an investigation into the environmental impacts associated with disposal operations at the MWL. The results of this Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) are documented in a report released in September 2002: “Report of the Mixed Waste Landfill Phase 2 RCRA Facility Investigation, Sandia National Laboratories, Albuquerque, New Mexico” SAND2002-2997. During the Phase 2 RFI, DOE and Sandia investigated the inventory of items present in the MWL and addressed data gaps identified in the work plan for the Phase 2 RFI. Records that were previously reported as lost or destroyed were found in storage and reviewed, and interviews with former and current SNL workers were conducted that helped clarify and document disposal practices. The complete unclassified waste inventory (i.e., no gaps in the waste disposal records) documenting the contents of the MWL by disposal pit and trench is provided as Appendix A of this report