2010-05-27_PERMIT FILE - P2010011 (4)

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POWERTECh IUSA) INC. Addendum 1- Notice of Intent for a Gamma Survey May-2010 1.0 Purpose of Activity The gamma survey data will supplement existing gamma survey data collected in the first phase of the baseline characterization effort (conducted in 2007-2008) regarding radiological parameters required by Federal and State agencies for submittal of a source materials license application. 2.0 Description of Gamma-Ray Survey Investigation A GPS-based gamma-ray survey (gamma survey) will be conducted across the site. Currently the site has been divided into three areas: well fields, processing areas (central processing and satellite facility areas) and the remaining permit area. The gamma survey in the well field and processing areas will be conducted along transects spaced at 100 meters. The gamma survey in the remaining permit areas will be conducted along transects spaced at 300 meters. If additional data are needed to delineate the limits of areas with potentially elevated gamma-ray responses, spacing adjustments will be made in the field to provide for delineation of the anomalous area(s). 3.0 Description of Methods and Equipment Employed for Gamma-Ray Survey Investigation Instrumentation utilized during the survey include: a Ludlum Model 44-10 (or equivalent) 2-inch by 2- inch sodium iodide high energy gamma-radiation detectors, each coupled to a Ludlum Model 2221 ratemeter/scaler that is, in turn, coupled to a Trimble ProXRS GPS Unit with a TSCe datalogger. The detection systems will be matched and calibrated to National Institute of Standards and Technology- traceable cesium-137 check sources and function-checked daily, prior to and after the work day. All areas will be surveyed at a speed of approximately 0.6 meter/second, with the detectors held at approximately 18 inches above ground surface. Gamma-ray count rates will be recorded every second, with individual count rates tagged with Colorado State Plane location coordinates. Field personnel will drive transects using all terrain vehicles (ATVs) or walk, carrying the instrumentation in backpacks. Exposure Rate Measurements: Direct exposure rate measurements will be made using a High Pressurized Ion Chamber (HPIC) in areas encompassing the expected range of exposure rates at the site. The HPIC data will be correlated to gamma-radiation count rates, using the same geometry and detection systems used in the GPS-based gamma-ray survey. The number and location of the HPIC correlation measurements will be based on the expected range of exposure rates as determined by existing and collected gamma survey data. Using this correlation, the count-rate data from the gamma survey will be converted to predicted exposure rates. Commencement Date: The field work will commence as soon as practicable following appropriate state approvals. The survey is projected to last five days using two field personnel and one Powertech representative. Addendum 1