Book Description

This plan provides the technical basis and associated protocols to support Phase 1 final status survey (FSS) data collection and interpretation as part of the West Valley Demonstration Project Phase 1 Decommissioning Plan process. This plan is consistent with the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). The Phase 1 Decommissioning Plan provides the relevant derived concentration guideline levels (DCGLs) for the Phase 1 radionuclides of interest. This plan includes protocols that will be applied to the deep excavations planned for Waste Management Area (WMA) 1 and WMA 2, for surface soils outside the WMA 1 and WMA 2 excavations that do not have contamination impacts at depths greater than one meter, and for areas that are used for Phase 1 contaminated soil lay-down purposes. All excavated and lay-down areas will be classified as MARSSIM Class 1 areas. Surface soils that have not been excavated, are not expected to exceed DCGLs, and do not have contamination impacts at depths greater than one meter will be divided into either Class 1 or Class 2 areas depending on the expected potential for surface soil contamination in those areas. The plan uses gamma scans combined with biased soil samples to address DCGLemc concerns. The plan uses systematic soil sampling combined with area factors to address DCGLw and DCGLemc concerns. The Sign test will be used to statistically evaluate DCGLw compliance. If the results from the characterization sampling and analysis plan (CSAP) data collection indicate that background may be a significant issue for Sign test implementation, the Wilcoxon rank sum (WRS) test will be used instead to demonstrate DCGLw compliance. A reference area will be selected on the basis of CSAP data results if the WRS test becomes a necessity. The WMA 1 excavation footprint includes approximately 476 foundation pilings that will be trimmed and left in place. Piling-specific systematic and biased sampling will be conducted to address concerns that these pilings may have served as preferential flow pathways into the underlying Lavery till. Phase 1 FSS data collection results will be summarized, presented, and interpreted in one or more FSS reports.