Site investigation report for Waste Area Grouping 4 at Oak Ridge National Laboratory. Volume 1, Text: Environmental Restoration Program

Waste Area Grouping (WAG) 4 is one of 17 WAGs within and associated with Oak Ridge National Laboratory (ORNL). WAG 4 is located south of the main facility along Lagoon Road. WAG 4 consists of three separate areas: Solid Waste Storage Area (SWSA) 4, a shallow-land-burial ground containing radioactive and potentially hazardous wastes; an experimental Pilot Pit Area, which includes a pilot-scale testing pit; and sections of two abandoned underground pipelines used for transporting liquid, low-level, radioactive waste. SWSA 4 is the largest site at WAG 4, covering approximately 23 acres. In the 1950s, SWSA 4 received a variety of low- and high-activity wastes, including transuranic wastes, all buried in trenches and auger holes. Recent surface water data, collected during monitoring of the tributary to White Oak Creek as part of WAG 2 investigations as well as during previous studies conducted at WAG 4, indicate that a significant amount of {sup 90}Sr is being released from the old burial trenches in SWSA 4. This release represents a significant portion of the ORNL off-site risk (DOE 1993). With recent corrective measures the proportion of the release has increased in 1995. A detailed discussion of the site history and previous investigations is presented in the WAG 4 Preliminary Assessment Report, ORNL/ER-271 (Energy Systems 1994b). In an effort to control the sources of the {sup 90}Sr release and to reduce the off-site risk, a site investigation was initiated to pinpoint those trenches that are the most prominent {sup 90}Sr sources