Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• Each detector used on the WVDP premises will undergo check source evaluations each day that itis used. The evaluations will follow a control chart developed and maintained for this purpose.The purpose of daily check source evaluations is to identify any deviations in expected detectorresponse.• A background reference area will be established and used for detector data quality evaluationpurposes (see Section 8.1). The background reference area will be surveyed with each detectorprior to the detector’s initial use on the WVDP premises. These data will be logged. A 100-m 2portion of the reference area will be covered in a manner that maintains relatively stable soilmoisture conditions (the cover will be removed prior to each survey). Data from the referencearea as a whole will be used to evaluate the range of detector background responses. Data fromthe covered area will be used to compare responses across detectors. The purpose of thesecomparisons is to allow the development of scaling factors, as necessary, to be used tostandardize gamma walkover data from different detectors. Key parameters of interest are theaverage activity concentration observed, the standard deviation (as a measure of backgroundvariability), and the 95% and 99% UTL for the background concentration.• A surface soil control point will be established and maintained through the life of Phase 1activities. Each detector used on the WVDP premises will have two 30-second measurementsmade at the control point each day it is deployed, one at the start of a day’s activities and one atthe end. These data will be recorded and a control chart developed and maintained for eachdetector. The purpose of this activity and the control chart is to identify transientsoil/meteorological conditions that may be adversely affecting detector response or trends indetector behavior that may be a concern.• Prior to surveying an area of interest, the potential for shine will be evaluated. Shine may be theresult of proximity to a building with a history of structural contamination in the case of surfacesoil scans, or it may be a product of geometry and contamination in excavation walls, as may bethe case in deep excavations. If shine is identified as a potential concern, the potential shineimpact will be assessed through the use of shielding and/or comparing results from 15-cm heightreadings with 1-m height readings. If a determination is made that shine impacts could besignificant, a mitigating strategy will be deployed. Examples of mitigating strategies wouldinclude the use of a shielded detector or the application of shine correction factors to acquiredRev. 1 86