The effect of desiccation on UMTRA Project radon barrier materials
The proposed US Environmental Protection Agency (EPA) groundwater standards (40 CFR 192) require that Uranium Mill Tailings Remedial Action (UMTRA) Project remedial action designs meet low numerical limits for contaminants contained in water or vapors exiting the disposal cell embankments. To meet the standards, a cover of compacted, fine-grained soil is placed over UMTRA Project embankments. One of the functions of this cover is to limit infiltration into the disposal cell . The hydraulic conductivity of this infiltration barrier must be low in order to reduce the resultant seepage from the base of the cell to the extent necessary to comply with the proposed EPA groundwater standards. Another function of this cover is to limit the emission of radon gas. The air permeability of the cover must be low in order to reduce radon emissions to comply with EPA standards. Fine-grained soils exposed to evaporation will dry. Continued exposure will cause shrinking that, if allowed to continue, will eventually result in the development of cracks. The results of the cracking could be an increase in the hydraulic conductivity and an increase in the air permeability. This could then allow additional infiltration and increased radon emissions. Cracking of the radon barrier has been noted at one UMTRA Project location. The potential for cracking of the radon barrier during construction has been addressed by requiring moistening of previously compacted surfaces prior to placing additional lifts. The efficacy of these treatments has not been verified. The potential for cracking after construction of the cover is completed has also not been examined. The purpose of this study is to evaluate the potential for cracking of the radon barrier both during construction and after completion of the cover. The effect of shrinkage cracking on the performance of the radon barrier will also be examined.
- Research Organization:
- USDOE Albuquerque Operations Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-82AL14086
- OSTI ID:
- 10134733
- Report Number(s):
- DOE/UMTRA--400663-0000; ON: DE93009469
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
053002
054000
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
COVERINGS
CRACKS
DRYING
EMBANKMENTS
FEED MATERIALS PLANTS
GROUND DISPOSAL
HEALTH AND SAFETY
HYDRAULIC CONDUCTIVITY
MILL TAILINGS
MOISTURE
RADIOACTIVE EFFLUENTS
RADON
SOILS
WASTE DISPOSAL AND STORAGE