Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• In 1990 and 1991 a second static direct exposure measurement program was conductedacross the WVDP premises (WVNSCO 1992). In the case of WMA 9, this effortprovided systematic coverage of its entire area on a 10-m grid. This data collection useddifferent instrumentation and protocols than the 1982 study, so the results are notquantitatively comparable. Figure H.11 shows these results overlain on a 1995 aerialphotograph. These data show marked elevated readings surrounding the Drum Cell.Given what was stored in the Drum Cell in this time frame, these readings may reflectshine from the building itself rather than elevated activity levels in the ground surface.• There are very little sampling data for WMA 9 available within ELIMS. In 1993 twosurface samples were collected pertinent to WMA 9, one in the extreme northwest cornerof WMA 9 and the second in the extreme southeast corner of WMA 9. Figure H.12shows the Cs-137 and Sr-90 results for these two samples. Both samples showed lowlevel Sr-90 impacts; although there was some evidence of Cs-137 as well, the Sr-90 weremore significant from the perspective of surface soil CG w requirements. Neither samplewas placed in a location where one would expect to find contamination. Table H.1identifies the number of samples analyzed for each of the 18 primary radionuclides ofinterest (ROI).• There are limited groundwater data for WMA 9 available within ELIMS. Figure H.13shows groundwater sampling locations color-coded by historical Sr-90 results. FigureH.14 shows groundwater sampling locations color-coded by historical tritium results. Thedetection limits for Sr-90 and tritium varied widely among ELIMS samples. 10 pCi/L and500 pCi/L were selected as thresholds for Sr-90 and tritium, respectively, because basedon ELIMS data results above these activity concentrations were consistently abovemethod detection limits and so indicative of contamination impacts rather than simplymeasurement error. In neither case was there significant evidence of groundwaterimpacts.H.6 Planned Phase 1 DP ActivitiesThe Drum Cell, the Subcontractor Maintenance Area hardstand, and the NDA Trench SoilContainer Area hardstand will be removed during Phase 1 (DOE 2009 Sections 3.1 and 7.10).Rev. 1 H-4