Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPbe substituted. Ex situ core scans will be used to identify the portion of a soil core that should bebiased sampled in response to elevated gamma scan readings.The performance of down-hole and ex situ core scans will be monitored by electronicallyrecording scan results, matching scans with corresponding soil core sample results, andevaluating the relationship between core scan results and corresponding soil core sample results.The general relationship evaluation process is similar to that for GWS detectors as described inSection 6.11.1.Data specific to down-hole and ex situ core scan performance will not be collected; however,performance will be evaluated and monitored as down-hole and ex situ core scan data setsbecome available. This evaluation will have two components:• Average background values and background variability for down-hole gamma scans andex situ soil core scans will be determined based on data from CSAP soil cores in whichno contamination is found present above background levels and from reference area datacollection. This variability will, in turn, allow the development of field investigationlevels that can be applied to down-hole and ex situ surveys to flag results that areinconsistent with background and potentially indicative of the presence of radionuclidesabove background levels.• In many cases, CSAP data collection protocols call for biased sampling of soil coresif/when elevated readings are encountered from either down-hole or ex situ surveys of thesoil cores. In these cases the resulting laboratory data will be matched with thecorresponding survey scan data, and the results used in combination with the backgrounddata sets to estimate minimum detectable concentrations.6.11.3 On-Site Cs-137 and Sr-90 Analytical PerformanceRapid screening of soil and groundwater samples for Cs-137 and Sr-90 is a key component of thevarious CSAP sampling strategies. Cs-137 and Sr-90 are believed to be the two radionuclides inenvironmental media that will drive Phase 1 decision-making for most of the WVDP premises.Rapid screening for Cs-137 and Sr-90 in environmental media will likely take place on-site in anappropriate facility.Rev. 1 49