X-ray Detector System Helps Evaluate Facility Contamination

 

Finding out where heavy metals are and where they aren't is getting easier with a new detector developed in a collaboration between Ames Laboratory and Iowa State University's Center for Non-Destructive Evaluation.

"Our first application is pinpointing the exact location of contamination in facilities that DOE is dismantling," says Joe Gray, co-developer of the K-edge heavy metal detector. "But quickly identifying heavy metals without contact will be helpful in many cleanup tasks and because of that, our detector is generating lots of interest."

Gray and Terry Jensen, the project's other co-investigator, have developed, designed, assembled and demonstrated a new portable detector that combines an x-ray source and spectrometry for quick identification and quantification of heavy metal contaminants in even large volumes of a wide variety of materials. It not only indicates which contaminants are present, but how much of a contaminant is where.

Successfully demonstrated for detecting contamination in facilities being decommissioned at DOE's Oak Ridge complex in Tennesse and at the Savannah River Site in South Carolina, the technology offers more rapid, sensitive and accurate measurement of facility contamination than other available detection methods. It works by using K-edge spectrometry to analyze x-rays that have been shined through a contaminated material, for instance a facility's structures. Scientists can determine the heavy metals present from that spectral analysis.

Already on the brink of making facility dismantling safer, quicker and more efficient by providing critical information, this technology holds promise for improving a host of other contaminant evaluations as well. Examples of other applications include rapid identification of soil contaminants, monitoring of new waste processing techniques and characterization of stored waste needing to be sorted for proper disposal.


 

BENEFITS:

  • Highly Sensitive Detection - The K-edge detector offers more sensitive and accurate measurement of heavy metal contaminants than techniques already available.
  • Resists Interference - Demonstrated on uranium samples in steel as thick as one and one-half inches, this detector is not hindered by the presence of materials other than the heavy metals it is designed to locate, as long as the thickness of the material being tested is appropriate for the X-rays to pass through.
  • Safe, Rapid Technique - Remote, in-situ analysis minimizes hazardous sample handling and transport as well as worker exposure to contamination. It also makes assessment of large facilities or areas more feasible.
  • Excellent Spatial Resolution - This technology can show exactly where heavy metal contaminants are, mapping them out for instance in a facility, in contaminated soils, or in stored or vitrified waste when sufficient time is available for making a series of measurements.
  • Multiple Applications - Already being applied to the assessment of components from contaminated facilities, this rapid, non-contact and nondestructive analytical technique with the ability to assess large areas can be adapted for other cleanup needs, including the surveying of soils for heavy metals, the monitoring of waste processing streams and the characterization of stored wastes.

BOTTOM LINE:

Rapidly identifying heavy metals even in large volumes of a wide variety of materials, Ames Lab's portable K-edge detector promises to improve a multitude of cleanup tasks, initially making the dismantling of contaminated facilities easier, safer and more efficient.


FOR MORE INFORMATION:

Joe Gray, e-mail: jngray@iastate.edu, phone: (515) 294-9745
Terry Jensen, e-mail: tcjensen@iastate.edu, phone: (515) 294-6788