100-DR-1 radiological surveys

Abstract

This report summarizes and documents the results of the radiological surveys conducted over the surface of the 100-DR-1 Operable Unit, Hanford Site, Richland, Washington. In addition, this report explains the survey methodology using the Ultrasonic Ranging and Data System (USRADS). The 100-DR-1 radiological survey field task consisted of two activities: characterization of the operable unit-specific background conditions and the radiological survey of the operable unit surface area. The survey methodology was based on utilization of USRADS for automated recording of the gross gamma radiation levels at or near 6 in. and at 3 ft from the surface soil. The purpose of the survey is to identify the location of unidentified subsurface radioactive material areas and any surface contamination associated with these areas. The radiological surveys were conducted using both a digital count rate meter with a NaI detector reporting in counts per minute (CPM) and a dose rate meter reporting micro-Roentgen per hour (uR) connected to a CHEMRAD Tennessee Corp. Series 2000 USRADS. The count rate meter was set for gross counting, i.e., Window ``out``. The window setting allows detection of low, intermediate, and high energy photons. The USRADS equipment is used to record the detector readings verses the locationmore » of the readings, generate a map of the survey area, and save the data on computer storage media.« less