A Change in Envirocare's Disposal Cell Design
Envirocare of Utah, Inc. operates a Low Level Radioactive Waste (LLRW) and 11e. disposal facility in the Utah west dessert. Envirocare disposes of LLRW in above ground cells. A seven-foot excavation lined with two feet of clay comprises the cell floor. Approximately 22 feet of waste is then placed in the cell in one-foot thick compacted lifts. The cover system consists of a nine-foot clay radon barrier and three-foot rock erosion barrier. This is required to prevent radon emissions at the surface of the radon barrier from exceeding 20 pCi/m2s, the radon release standard in Criterion 6 of 10 CFR 40. The required thickness of the current clay radon barrier cover was based on the original radon flux model used to evaluate the safety of Envirocare's proposed LLRW and 11e.(2) license operations. Because of the lack of actual measurements, universally conservative values were used for the long-term moisture content and the radon diffusion coefficients of the waste and radon barrier material. Since receiving its license, Envirocare has collected a number of samples from the radon barrier and waste material to determine their actual radon attenuation characteristics, including the long-term moisture content and the associated radon diffusion coefficient. In addition, radon flux measurements have been performed to compare the model calculations with the calculated results. The results from these analyses indicate that the initial modeling input parameters, specifically the long-term moisture content and the radon diffusion coefficient, are more conservative than that needed to ensure compliance with the applicable regulatory requirements.
- Research Organization:
- Envirocare of Utah, USA (US)
- Sponsoring Organization:
- Sponsor not identified (US)
- OSTI ID:
- 828255
- Resource Relation:
- Conference: Waste Management 2002 Symposium, Tucson, AZ (US), 02/24/2002--02/28/2002; Other Information: PBD: 25 Feb 2002
- Country of Publication:
- United States
- Language:
- English
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