Closure Report for Corrective Action Unit 240: Area 25 Vehicle Washdown Nevada Test Site, Nevada

The Area 25 Vehicle Washdown, Corrective Action Unit (CAU) 240, was clean-closed following the approved Corrective Action Decision Document closure alternative and in accordance with the Federal Facility Agreement and Consent Order (FFACO, 1996). The CAU consists of thee Corrective Action Sites (CASs): 25-07-01 - Vehicle Washdown Area (Propellant Pad); 25-07-02 - Vehicle Washdown Area (F and J Roads Pad); and 25-07-03 - Vehicle Washdown Station (RADSAFE Pad). Characterization activities indicated that only CAS 25-07-02 (F and J Roads Pad) contained constituents of concern (COCs) above action levels and required remediation. The COCs detected were Total Petroleum Hydrocarbons (TPH) as diesel, cesium-137, and strontium-90. The F and J Roads Pad may have been used for the decontamination of vehicles and possibly disassembled engine and reactor parts from Test Cell C. Activities occurred there during the 1960s through early 1970s. The F and J Roads Pad consisted of a 9- by 5-meter (m) (30- by 15-foot [ft]) concrete pad and a 14- by 13-m (46-by 43-ft) gravel sump. The clean-closure corrective action consisted of excavation, disposal, verification sampling, backfilling, and regrading. Closure activities began on August 21, 2000, and ended on September 19, 2000. Waste disposal activities were completed on December 12, 2000. A total of 172 cubic meters (223 cubic yards) of impacted soil was excavated and disposed. The concrete pad was also removed and disposed. Verification samples were collected from the bottom and sidewalls of the excavation and analyzed for TPH diesel and 20-minute gamma spectroscopy. The sample results indicated that all impacted soil above remediation standards was removed. The closure was completed following the approved Corrective Action Plan. All impacted waste was disposed in the Area 6 Hydrocarbon Landfill. All non-impacted debris was disposed in the Area 9 Construction Landfill and the Area 23 Sanitary Landfill