Review of the radioactive and thermal stability of low density polyethylene encapsulated nitrate salt waste

Low density polyethylene extrusion is under consideration as a stabilization technique for the treatment of several mixed waste streams produced at the Rocky Flats Plant (RFP). The main focus of this development is the nitrate sat waste stream; Rocky Flats' largest volume mixed waste stream. This waste stream is primarily composed of the nitrate sats of various metals, including some metals that are land disposal restricted (LDR) under the Resource Conservation and Recovery Act (RCRA). The specific activity of the nitrate sats is approximately 300 to 500 picocuries per gram, making this a low level mixed waste stream. Because the dried soft fails leachability and dispersable solid requirements, additional treatment is required to convert this waste into a form acceptable for land disposal. This review is being conducted to determine whether the specific activity of the nitrate salts is low enough to allow their safe stabilization by polyethylene (PE) encapsulation.