Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPreleased an estimated 200 gallons of radioactive nitric acid with approximately 93 Ci Sr-90(DOE 2009 Table 2-17).C.4.3Other Known and Suspected ReleasesC.4.3.1Waste Tank Farm OperationsPotentially Affected Media: subsurface soil, groundwaterPotentially Affected WMAs: 3The Waste Tank Farm system is expected to contain residual radioactivity. The total activity inthe 40 underground lines in the immediate vicinity of the Waste Tank Farm has been estimated tobe approximately 117 curies in 2004, with more than 99 percent of this activity associated withCs-137 and Sr-90. The integrity of these lines is not known. There is no evidence that any of thefour waste storage tanks themselves have ever leaked.C.4.3.2Waste Tank Farm Valve Pit SpillPotentially Affected Media:Potentially Affected WMAs:surface soil, subsurface soil, groundwater1, 2, 3, 4, 5, 6 (North Plateau Groundwater Plume)In 1985, a spill of radioactive water occurred in a valve pit located northwest of Tank 8D-2,between Tank 8D-1 and Tank 8D-2. A condensate line failed at its flanged valve bolts.Approximately 500 gallons were released at 4.6 E-02 uCi/mL gross beta and 4E-03 uCi/mL H-3.Some condensate flowed out of the valve pit into the drainage ditch extending towards the OldHardstand in WMA 5 and/or towards WMA 2. The radioactive condensate reached the point inthe drainage ditch where the ditch turns to the northeast, near the corner of the New/OldHardstand. At this point, the ditch was blocked to prevent further downstream flow. The releaseprimarily impacted surface soil in WMA 3. Contaminated soil was removed and placed intocontainers (DOE 2004 Section 4.4.2; DOE 2009 Table 2-18; DOE 2010 Section 3.11.5). Thisrelease likely has contributed to the North Plateau Groundwater Plume.Rev. 1 C-7