THE TRU WASTE INVENTORY UPDATE SUPPORTING PERFORMANCE ASSESSMENT AT THE WASTE ISOLATION PILOT PLANT

The Waste Isolation Pilot Plant (WIPP), located near Carlsbad, New Mexico, is a deep geologic repository for the disposal of transuranic (TRU) wastes generated by atomic energy defense activities. The WIPP Land Withdrawal Act (LWA) requires the U.S. Department of Energy (DOE) to submit to the U.S. Environmental Protection Agency (EPA) documentation of WIPP’s continuing compliance with the disposal regulations, 40 CFR Part 191, Subparts B and C, not later than five years after initial receipt of waste for disposal at the repository, and every five years thereafter until the decommissioning of the facility is completed. The first five-year period ended on March 27, 2004. The Compliance Recertification Application (CRA), completed in 2004, demonstrates WIPP’s continuing compliance and requests that EPA recertify the repository. TRU waste inventory information was initially compiled for use in the 1998 certification of WIPP. This inventory information was updated for use in the WIPP Performance Assessment (PA) calculations that support the WIPP re-certification. Los Alamos National Laboratory-Carlsbad Operations conducted the inventory update for the PA. Inventory data collection, entry, verification and validation to ensure data quality was maintained throughout the TRU waste inventory update processes were conducted under Sandia National Laboratories Quality Assurance Program. Inventory data were collected and entered into the Transuranic Waste Baseline Inventory Database (TWBID). This database was qualified and used to produce data used in the PA calculations. The inventory data provided for these calculations included: 1) volumes (stored, projected, and emplaced waste); 2) radionuclide activity concentrations; 3) waste material densities parameters; 4) estimates for the masses of selected complexing agents; 5) estimates for the masses of selected oxyanions; 6) cement mass estimates; 7) pyrochemical salt information; and 8) information on the types and amounts materials used to emplace the waste in WIPP. LA-UR-04-4747