Concerns about inadvertent releases of radioactive liquids to the environment from nuclear power plants have prompted consideration of ways to provide early leak detection in the subsurface external to the structures of the facilities. Approaches to this include two-dimensional and three-dimensional geophysical methods providing information parameters that may be related to leaks, such as changes in conductivity/resistivity, permittivity, or temperature.
HGI has been advancing the field of leak detection and location in HDPE lined ponds, landfills, and heap leaches using electrical methods for over 18 years. To demonstrate the effectiveness of locating leaks using electrical methods HGI constructed a scaled pond using a 10×15 foot geomembrane. In addition, HGI tested the applicability of a low cost permanent monitoring system, designed to be installed prior to, and beneath the liner, detecting the first signs of a leak and providing locations of leaks.
Surface-based geophysical methods are routinely used in industry for the purposes of non-intrusive detection and mapping of pipeline leaks. However, these situations usually involve current and ongoing leaks resulting in freshly contaminated soil. In contrast, the majority of Hanford pipeline leaks are historic and provide a weak physical property contrast between soil and leak plume. To assess if an innovative suite of electromagnetic techniques could be used to map elevated soil conductivity caused by these historic releases in the presence of an even more electrically conductive metallic pipe, an electromagnetic geophysical survey was conducted to image historical leaks from a waste transfer pipeline.