Field demonstration of improved shallow land burial practices for low-level radioactive solid wastes: preliminary site characterization and progress report. [Trench liners and grout for improving shallow land burial

Abstract

A 5-year field demonstration (ETF) of improved shallow land burial practices for low-level radioactive solid wastes in a humid environment evaluates the use of a trench liner and grout as alternate trench treatments for improving shallow land burial site performance in the humid East. The ETF is located within the Copper Creek thrust block of the Valley and Ridge Province of east Tennessee and is underlain by strata of the Middle to Late Cambrian Conasauga Group. The Maryville Limestone formation, which is composed of ribbon-bedded and interclastic limestones and dark grey shales and mudstones, comprises the bedrock immediately beneath the site. The bedrock and residuum structure are characterized by anticlinal folds with numerous joints and fractures, some of which are filled with calcite. Seismic and electrical resistivity geophysical methods were useful in characterizing the thickness of residuum and presence of structural features. Soils are illitic and range from podzolic to lithosols to alluvial in the vicinity of the ETF, but the original soil solum was removed in 1975 when the mixed hardwood forest was cleared and the site was planted in grasses. The remaining residuum consists of acidic soil aggregate and extensively weathered siltstone and sandstone which exhibit the originalmore » rock structure. Mean annual precipitation at the site is 1500 mm, although during the initial study period (10-1-80 to 9-30-81) the annual total was 939 mm. Runoff was estimated to be about 50% of the precipitation total, based on observations at two Parshall flumes installed at the site. Storm runoff is quite responsive to rainfall, and the lag time between peak rainfall and runoff is less than 15 min during winter storms. Tracer studies of the ground-water system, suggest that ground-water flow has two distinct components, one associated with fracture flow and the other with intergranular flow.« less