AX tank farm waste inventory study for the Hanford Tanks Initiative (HTI) project

Abstract

In May of 1996, the US Department of Energy implemented a four-year demonstration project identified as the Hanford Tanks Initiative (HTI). The HTI mission is to minimize technical uncertainties and programmatic risks by conducting demonstrations to characterize and remove tank waste using technologies and methods that will be needed in the future to carry out tank waste remediation and tank farm closure at the Hanford Site. Included in the HTI scope is the development of retrieval performance evaluation criteria supporting readiness to close single-shell tanks in the future. A path forward that includes evaluation of closure basis alternatives has been outlined to support the development of retrieval performance evaluation criteria for the AX Farm, and eventual preparation of the SEIS for AX Farm closure. This report documents the results of the Task 4, Waste Inventory study performed to establish the best-basis inventory of waste contaminants for the AX Farm, provides a means of estimating future soil inventories, and provides data for estimating the nature and extent of contamination (radionuclide and chemical) resulting from residual tank waste subsequent to retrieval. Included in the report are a best-basis estimate of the existing radionuclide and chemical inventory in the AX Farm Tanks, an estimate of the nature and extent of existing radiological and chemical contamination from past leaks, a best-basis estimate of the radionuclide and chemical inventory in the AX Farm Tanks after retrieval of 90 percent, 99 percent, and 99.9 percent of the waste, and an estimate of the nature and extent of radionuclide and chemical contamination resulting from retrieval of waste for an assumed leakage from the tanks during retrieval.