Surface Geophysical Exploration of Tx-Ty Tank Farms at the Hanford Site Results of Background Characterization With Ground Penetrating Radar

Abstract

Ground penetrating radar surveys of the TX and TY tank farms were performed to i d e n t i existing infrastructure in the near surface environment. These surveys were designed to provide background information supporting Surface-toSurface and Well-to-Well resistivity surveys of Waste Management Area TX-TY. TRADEMARK DISCLAIMER. Reference herein to any specific commercial pmduct, process. or service by trade name, trademark. manufacturer, or otherwise, does not necessarily constitute or imply its endorsement. recommendation, or favoring by the United Stales Government or any agency thereof or its contractors or submntractors The results of the background characterization confirm the existence of documented infrastructure, as well as highlight locations of possible additional undocumented subsurface metallic objects.Figures ES-1 and ES-2 show the results of the interpreted pipe infrastructure within the north and south parts of TX tank farm. With the frequency of the GPR at 250 megahertz, pipes within 10 feet of the surface could be imaged effectively. The depth of investigation depends on the loessy nature of the soil, which is controlled by mineral and water content.The use of a real time kinematic survey grade global positioning system on this survey improved the survey accuracy from sub-meter in previous SGE surveys to sub-centimeter.It is recommended that if deeper surveying is needed then a lower frequency ground penetrating radar antenna be utilized. However, a lower frequency antenna has a larger minimum target size for detection.