Soil Sampling to Demonstrate Compliance with Department of Energy (DOE) Authorized Limits for the Radiological Release of Hanford Reach National Monument Lands in Accordance with DOE Order 5400.5 Requirements
B.G. Fritz1; R.L. Dirkes1; and W.M. Glines2 (1Pacific Northwest National Laboratory; 2Department of Energy - Richland Operations Office)
In June 2000, a Presidential Proclamation created the Hanford Reach National Monument (HRNM) within the boundaries of the Department of Energy (DOE) Hanford Site. Approximately 143,000 acres of land, including the Wahluke Slope, Saddle Mountain, Fitzner/Eberhardt Arid Lands Ecology Reserve (ALE), and McGee Ranch/Riverland units, within the HRNM is anticipated to be transferred to the Department of Interior. The DOE Richland Operations Office, in compliance with the requirements of DOE Order 5400.5, Radiation Protection of the Public and the Environment, evaluated the potential for residual radioactive contamination on these lands, developed radiological release criteria, i.e., authorized limits, and prepared a Soil Sampling and Analysis Plan (SAP) for the ALE Unit of the HRNM. The Visual Sample Plan (VSP) computer program was used to select the number and locations of soil samples necessary to demonstrate at the 99% confidence level that radionuclide concentrations in soil are below the Authorized Limits. In addition, sample locations were selected to account for variations due to differences in elevation and in areas where contaminants may be accumulated. Soil sampling was conducted across the ALE Unit in the spring of 2004 in accordance with the approved SAP. Analytical results are presented that demonstrate radionuclide concentrations on ALE are in the range observed routinely in the past, similar to "reference" and Hanford soil background concentrations, and far below the approved authorized limits.