Electrical properties of Topopah Spring tuff as a function of saturation

Much attention has been focused on the hydrologic properties of tuff from the potential nuclear waste repository at Yucca Mountain, Nevada. The successful characterization of the near-field environment of the potential repository depends on the ability to understand and predict the movement of water within the matrix and fractures when the rock mass is heated by nuclear waste. This understanding will come only after many combined laboratory experiments, field tests, and model calculations have been performed. Electrical properties, including electrical resistivity and dielectric permittivity, have been utilized in past studies to infer water content in partially saturated rocks. In this study we determine the electrical properties of Topopah Spring tuff from Yucca Mountain (Area 25), and Area 3, Nevada Test Site (NTS), NV, as a function of water content. These results will be used to (1) study the electrical properties of ted rocks as functions of saturation and water chemistry; (2) relate the observed electrical properties to the distribution of water and to the rnicrogeometry of the rock; and (3) to create a database of electrical resistivity ({rho}) and relative dielectric permittivity ({kappa}{prime}) versus water content (Sw) and temperature for rocks within the potential repository horizon. The database will be used both in laboratory experiments and field tests to determine the moisture content in rocks based on measured electrical properties