Geochemical effects on the behavior of LLW radionuclides in soil/groundwater environments
- Pacific Northwest Lab., Richland, WA (United States)
Assessing the migration potential of radionuclides leached from low-level radioactive waste (LLW) and decommissioning sites necessitates information on the effects of sorption and precipitation on the concentrations of dissolved radionuclides. Such an assessment requires that the geochemical processes of aqueous speciation, complexation, oxidation/reduction, and ion exchange be taken into account. The Pacific Northwest National Laboratory (PNNL) is providing technical support to the U.S. Nuclear Regulatory Commission (NRC) for defining the solubility and sorption behavior of radionuclides in soil/ground-water environments associated with engineered cementitious LLW disposal systems and decommissioning sites. Geochemical modeling is being used to predict solubility limits for radionuclides under geochemical conditions associated with these environments. The solubility limits are being used as maximum concentration limits in performance assessment calculations describing the release of contaminants from waste sources. Available data were compiled regarding the sorption potential of radionuclides onto {open_quotes}fresh{close_quotes} cement/concrete where the expected pH of the cement pore waters will equal to or exceed 10. Based on information gleaned from the literature, a list of preferred minimum distribution coefficients (Kd`s) was developed for these radionuclides. The K{sub d} values are specific to the chemical environments associated with the evolution of the compositions of cement/concrete pore waters.
- Research Organization:
- Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)
- OSTI ID:
- 240876
- Report Number(s):
- CONF-951209-; ON: DE96005882; TRN: 96:013535
- Resource Relation:
- Conference: 17. low-level radioactive waste management conference, Phoenix, AZ (United States), 12-14 Dec 1995; Other Information: PBD: [1995]; Related Information: Is Part Of Proceedings: 17th annual US Department of Energy low-level radioactive waste management conference; Lake, D. [ed.]; PB: 480 p.
- Country of Publication:
- United States
- Language:
- English
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