Particle Size Distribution Data From Existing Boreholes at the Immobilized Low-Activity Waste Site

Abstract

The U.S. Department of Energy's (DOE) Hanford Site has the most diverse and largest amount of radioactive tank waste in the United States. High-level radioactive waste (HLW) has been stored in large underground tanks since 1944; Vitrification and onsite disposal of the low-activity waste (LAW) fi-action are embodied in the strategy described in the Tri-Party Agreement (Ecology et al. 1998). The lowactivity waste will be disposed of in the Inirnobilized Low-Activity Waste site (ILAW), which will be located in 200 East Area. This frost ILAW borehole (299-E 17-21) was drilled in April of 1998 as part of the geology characterization work for the Performance Assessment. Reidel and Horton (1999) issued a geologic data package that integrated the first ILAW borehole with the existing geologic information on the ILAW site. This report provides particle size distribution data for samples near the ILAW site that were archived in the Hanford Geotechnical Sample Library. The data are to support the ILAW 2005 Performance Assessment. Seventy-nine sediment samples were analyzed from four boreholes. Samples were collected from every ten feet in the boreholes. Eighty percent of the samples were classified as slightly gravelly sand. Fifteen percent were classified as gravelly sand, gravelly silty sand, or sandy gravel. These data indicate that the particle size of the sediment is consistent across the ILAW site and is dominated by sand in the upper part of the Hanford formation with more gravel rich units in the Iower part. ...