An efficiency function model of segmented gamma scanning for measuring radioactive waste drum

Area of Science:

• Nuclear Engineering
• Radiochemistry
• Waste Management

Background:

• Segmented gamma scanning (SGS) is crucial for radioactive waste drum characterization.
• Accurate efficiency calibration is vital for reliable radioactivity reconstruction in SGS.
• Existing calibration methods face challenges like time lag and experimental source limitations.

Purpose of the Study:

• To propose an improved efficiency function model and calibration method for SGS.
• To address limitations in current SGS efficiency calibration.
• To enhance the accuracy of radioactivity measurements in waste drums.

Main Methods:

• Developed a Geant4-based SGS system model to compute segment efficiency.
• Established an efficiency calibration function using the model and experimental parameters.
• Utilized polyethylene waste drum samples with 137Cs/60Co point sources for experimental validation.

Main Results:

• The new method demonstrated reduced relative deviations in reconstructed radioactivity.
• Single point source deviations ranged from -50.48% to 43.69%.
• Multi-point source deviations within a segment or drum ranged from -27.88% to 3.57%.

Conclusions:

• The proposed efficiency function model and SGS calibration method are effective.
• The approach successfully improves the accuracy of radioactivity reconstruction in waste drums.
• Experimental results validate the enhanced performance of the new calibration technique.