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Title: Moisture content and unsaturated conditions in UMTRA project radon barriers

Technical Report ·
DOI:https://doi.org/10.2172/6345305· OSTI ID:6345305

A typical Uranium Mill Tailings Remedial Action (UMTRA) Project disposal facility consists of uranium tailings and other contaminated materials covered by a three to six foot thick radon barrier and six inches of filter sand, overlain by one foot of erosion-protection riprap. To comply with the proposed US Environmental Protection Agency groundwater protection standards applicable to the UMTRA Project, groundwater concentration limits of hazardous constitutents cannot be exceeded at the point of compliance, which is the downgradient limit of the waste management area. The typical radon barrier has a saturated hydraulic conductivity of approximately 1 {times} 10{sup {minus}7} centimeters per second (cm/s). Long-term seepage rates from a disposal facility with an unsaturated radon barrier may permit the concentration limits to be met at the point of compliance. Field studies were undertaken to measure the percent saturation and the relation of percent saturation to soil tension, and to predict the hydraulic conductivity as a function of percent saturation in radon barriers at three UMTRA Project disposal facilities that have been completed for up to two years. Presently typical covers have been completed at the Shiprock, Clive, and Burrell sites, and they are planned or under construction at the Ambrosia Lake, Green River, Lakeview, Mexican Hat, Slick Rock, and Tuba City sites. 2 refs., 13 figs., 1 tab.

Research Organization:
USDOE Albuquerque Operations Office, NM (USA). Uranium Mill Tailings Project Office
Sponsoring Organization:
DOE/NE
OSTI ID:
6345305
Report Number(s):
DOE/UMTRA-400656; ON: DE91005816; TRN: 91-004395
Country of Publication:
United States
Language:
English