Tuff reaction vessel experiment [electronic resource].
- Livermore, Calif : Lawrence Livermore National Laboratory, 1986.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 38 pages : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- A laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples of the kind that will be used to store nuclear waste were placed in water inside tuff vessels, and then the tuff vessels were placed in water inside Teflon containers. Glass-component leach rates and migration through the tuff were measured for samples of the ATM-8 actinide glass, which is a PNL 76-68 based glass with low levels of ⁹⁹Tc, ²³⁷Np, ²³⁸U, and ²³⁹Pu to simulate wastes. Disc samples of this glass were leached at 90°C to 30, 90, and 1983 days inside tuff vessels using a natural groundwater (J-13 well-water) as the leachant. Some samples were held by 304L stainless steel supports to evaluate the effect of this metal on the release rate of glass constituents. At the end of each leaching interval, the J-13 water present inside and outside the rock vessel was analyzed for glass components in solution. On the basis of these analyses, B, Mo, and Tc, appear to migrate through the rock at rates that depend on the porosity of each vessel and the time of reaction. U, Np, and Pu were found only in the inner leachate. Na, Si, and Sr are present in the rock as well as in the J-13 water, and the addition of these elements from the glass could not be determined. Normalized elemental mass loss values for B, Mo, and Tc were calculated using the combined concentrations of the inner and outer leachates and assuming a negligible retention on the rock. The maximum normalized release was 2.3 g/m² for Tc. B, Mo, Tc, and Np were released linearly with respect to each other, with B and Mo released at about 85% of the Tc rate, and Np at 5-10% of the Tc rate. Plutonium was found at low levels in the inner leachate but was strongly sorbed on the steel and Teflon supports. Neptunium was sorbed to a lesser extent.
- Report Numbers:
- E 1.99:ucrl--53735
- Other Subject(s):
- Published through SciTech Connect.
Bazan, F.; Rego, J.H.
- Funding Information:
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