Treatment, storage, and disposal alternatives for the gunite and associated tanks at the Oak Ridge National Laboratory, Oak Ridge, Tennessee

Abstract

The gunite and associated tanks (GAAT) are inactive, liquid low-level waste tanks located in and around the North and South Tank Farms at Oak Ridge National Laboratory. These underground tanks are the subject of an ongoing treatability study that will determine the best remediation alternatives for the tanks. As part of the treatability study, an assessment of viable treatment, storage, and disposal (TSD) alternatives has been conducted. The report summarizes relevant waste characterization data and statistics obtained to date. The report describes screening and evaluation criteria for evaluating TSD options. Individual options that pass the screening criteria are described in some detail. Order-or-magnitude cost estimates are presented for each of the TSD system alternatives. All alternatives are compared to the baseline approach of pumping all of the GAAT sludge and supernate to the Melton Valley Storage Tank (MVST) facility for eventual TSD along with the existing MOST waste. Four TSD systems are identified as alternatives to the baseline approach. The baseline is the most expensive of the five identified alternatives. The least expensive alternative is in-situ grouting of all GAAT sludge followed by in-situ disposal. The other alternatives are: (1) ex-situ grouting with on-site storage and disposal at Nevada Test Site (NTS); (2) ex-situ grouting with on-site storage and disposal at NTS and the Waste Isolation Pilot Plant (WIPP); and (3) ex-situ vitrification with on-site storage and disposal at NTS and WIPP.