This report documents the evolution of the surface geophysical exploration program and highlights some of the most recent successes in imaging conductive targets related to past leaks within and around Hanford's tank farms.

This report resents the results of the background characterization of the cribs, trenches, and tile fields within and around the B-BX-BY Waste Management Area.

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.

(1) Document Number: RPP-RPT-36893. Rev. 0 EXECUTIVE SUMMARYThis report documents the results of preliminary surface geophysical exploration activities performed between September and October 2007 at the waste management areas surrounding the TX and TY tank farms. The TX-TY tank farms are located in the 200 West Area of the U.S. Department of Energy's Hanford Site in Washington State. The objective of the preliminary investigation was to acquire background characterization information using magnetic gradiometry (Mag) and electromagnetic induction (EM) methods to understand the spatial distribution of buried metallic objects that could potentially interfere with the results of a subsequently completed high resolution resistivity survey.Data coverage included a total of approximately 82 acres over five main focus areas: the eastern cribs (216-T-26 through 216-T-28), northern cribs (216-T-36-13 and T216-T-13), south tile field (216-T-19), western trenches (216-T-21 through 216-T-25), and the area directly west ofthe TX farm.Results of the background characterization indicate that there are several areas located around the tank farms that have large metallic subsurface debris or metallic infrastructure that will likely influence the resistivity results.Figure ES-1 shows the results of the magnetic vertical gradient response patterns, in nanoTeslas (nT). The vertical magnetic gradient reveals some shallow ferrous materials most noticeably between the eastern TX farm fence and the eastern survey boundary. Several other linear features appear within the survey area and are exhibited by the red and blue color contours. Areas that have no buried metallic objects are represented by yellow hues. Interpreted responses were correlated to available infrastructure maps and then grouped into three classes based on how they might influence resistivity data: below ground (pipes and utilities), above ground (overhead electric lines, surface transfer lines, structures), and roads (with different material properties and increased moisture).Figure ES-2 shows the electrical conductivity survey results using the 10 kHz frequency. The color scale was developed so that background conditions are represented by orange and yellow colors and high conductivity features are shown in red tones. The figure shows several high conductivity regions that could be indicative of subsurface metals, including stainless-steel pipes. The features correlate with the results of the magnetic survey, which provides the ability to segregate ferrous metals that will appear on the Mag and EM data, and non-ferrous metals that will only be visible only on the EM results. Unlike the Mag survey, overhead electric lines are visible in the electromagnetic survey, most noticeably west of the TX-TY farms. ES-1RPP-RPT-36893, Rev. 0

This document evaluates the feasibility of in-situ detection of technetium-99 in Hanford Site vadose zone soils (the soils between the surface and groundwater) using laboratory tests.The detector system performs adequately for high technetium concentration, but more development and laboratory testing is needed before field demonstration is performed.TRADEMARK DISCLAIMER. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors. The detector system performs adequately for high technetium concentration, but more development and laboratory testing is needed before field demonstration is performed.The detector system clearly detects a 100.8 nanoCurie surface-deposited source of 99 Tc. The display system monitoring the tests shows that the detection system and the associated electronics can detect