High Frequency Electromagnetic Tomography

Central to understanding waste package performance is a thorough understanding of local hydrology over the package lifetime. Many techniques can be used to define this hydrology. Unfortunately, most of these techniques require perturbing the system by the drilling of many boreholes. Therefore, noninvasive methods are important. High Frequency Electromagnetic (HFEM) tomography is one technique that can be used to characterize remotely near-field hydrology. By cross-hole transmission of 200-MHz electromagnetic signals and tomographic reconstruction of these data, one can map the electromagnetic permittivity and attenuation rate of the rock mass in the plane between the boreholes. These maps can then be interpreted in terms of moisture content changes in the region remote from the boreholes