Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPNFS Shallow Special Holes. Approximately 230 NFS Shallow Special Holes are located in thenorthern and western portions of the U-shaped NFS Waste Disposal Area.At least 22 1,000-gallon tanks containing a mixture of spent n-dodecane and tributyl phosphate inabsorbent material were disposed in several of these Shallow Special Holes during the late 1960sand the early 1970s. Eight of these tanks in Special Holes 10 and 11 were believed to be thesource of n-dodecane and tributyl phosphate detected in a nearby monitoring well on November1983.The Shallow Special Holes are typically about 20 feet deep, with various lengths and widths;most are about 12 feet wide and 20 to 30 feet long. The length and width of each hole variedaccording to the quantity of waste requiring disposal at each disposal event, and the dimensionsof large waste items such as failed equipment. Miscellaneous wastes, other than leached hulls orrelated spent fuel debris, were packaged in several types of containers, including steel drums,wooden crates, and cardboard boxes.The following actions were taken by the WVDP between October 1985 and May 1987 to mitigatethe migration of the n-dodecane and tributyl phosphate from Special Holes 10 and 11:• The eight 1,000-gallon tanks containing the n-dodecane/tributyl phosphate contaminatedabsorbents were removed.• The tanks were size-reduced, contaminated absorbents and soils were removed, and all wastewas packaged for disposal.• Liquid n-dodecane and tributyl phosphate was removed and solidified into a qualified wasteform suitable for disposal.• Special Holes 10 and 11 were backfilled.• Approximately 9,700 cubic feet of packaged contaminated soil, contaminated absorbents,size-reduced tanks, and solidified n-dodecane and tributyl phosphate were generated duringthis removal activity.WVDP Trenches. Twelve WVDP Trenches are present; most of these trenches are in the parcelof land located inside the U-shaped NFS Waste Disposal Area.Rev. 1 G-2