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Accelerating the pace of cleanup through innovation

ORAU health physicists enhance capabilities for customers

ORAU employee uses a large-volume gamma detector to measure radiation

The ORAU-developed, large-volume gamma detector is ideal for quickly surveying bigger land-areas and can be mounted to a vehicle or pushed manually as shown here.

In FY13, ORAU continued to support DOE’s cleanup mission across the complex by completing independent verification for more than 200,000 acres and more than 3,500-square-feet of facilities at three major DOE sites, including Hanford, Paducah and Oak Ridge. The team also performed the sampling and analysis of 13 abandoned legacy liquid waste containers located at the East Tennessee Technology Park in Oak Ridge. The work, which totaled more than 37,000 field- and laboratory-related safe-work hours, was completed along with the help of several ORAU innovations such as a large-volume gamma detector for surveying large land-areas and a non-intrusive method for quantifying radioactivity in pipes and ductwork.

Tackling large land-areas with ease

The standard process for conducting radiological surveys uses a gamma-walkover approach and handheld radiation detectors, but because remediation sites can sometimes exceed hundreds or even thousands of acres, ORAU health physicists have built a larger detector that can expeditiously survey bigger land areas. Comprised of two four-inch by five-inch sodium iodide gamma detectors that had once been part of a whole body counting system, the detector can be mounted to a vehicle and easily interface with currently used systems. Encapsulated in a rugged military case, all of the detector’s electronics are shock-mounted, weatherproof and easy to use. The large detector has already been used to survey 75 acres at the East Tennessee Technology Park and is expected to support cleanup efforts at the Hanford Nuclear Reservation in FY14.

Gathering radiological data from within intricate air-handling systems

The size, shape and hostile condition of ductwork and ventilation pipes can make the process of accurately quantifying contamination within air-handling systems very complicated. To address this difficulty, ORAU health physicists have developed a specialized survey method that uses a gamma detector resilient enough to withstand the abuse that comes from being placed at the bottom of the duct and pulled through the ducting. The round shape of the detector makes navigation of bends and elbows within the ductwork much simpler with less potential for the detector to become jammed at a corner or hung-up on other obstacles within the ductwork.

Using the new pipe detector, ORAU health physicists measure the gamma radiation levels within each system and then quantify the beta activity using the gamma measurements as a surrogate. Correction factors are specified in a technical basis document that outlines the calibration process, efficiency determination and the calculation method for quantifying the total amount of cesium-137 (Cs-137) and Cs-134 contamination within air-handling systems.

Though developed using non-ORISE funds, this new approach is expected to enhance capabilities offered to DOE by providing a non-intrusive method to quantify radioactivity within systems. Not only are costs and schedules reduced, but the risk of accident or injury that could result from intrusive sampling is also greatly reduced.

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