Long-term surveillance plan for the Canonsburg, Pennsylvania, disposal site

This document establishes elements of the US Department of Energy`s (DOE) Long-Term Surveillance Plan for the Canonsburg, Pennsylvania, disposal site. The US Nuclear Regulatory Commission (NRC) will use this plan in support of license issuance for the long-term surveillance of the Canonsburg site. The Canonsburg (CAN) site is located within the borough of Canonsburg, Washington County, in southwestern Pennsylvania. The Canonsburg site covers approximately 30 acres (74 hectares). The disposal cell contains approximately 226,000 tons (241,000 tons) of residual radioactive material (RRM). Area C is southeast of the Canonsburg site, between Strabane Avenue and Chartiers Creek. Contaminated soils were removed from Area C during the remedial action, and the area was restored with uncontaminated fill material.After this cleanup, residual quantities of thorium-230 were detected at several Area C locations. The remedial action plan did not consider the ingrowth of radium-226 from thorium-230 as part of the Area C cleanup, and only two locations contained sufficient thorium-230 concentrations to result in radium-226 concentrations slightly above the US Environmental Protection Agency (EPA) standards