비정형 공정부산물 In-Situ 감마선 측정 정확도 향상을 위한효율교정 모델 최적화 방법 개발
Development of an Efficiency Calibration Model Optimization Method for Improving In-Situ Gamma-Ray Measurement for Non-Standard NORM Residues
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In In-situ radioactivity measurement techniques, efficiency calibration models use predefinedmodels to simulate a sample’s geometry and radioactivity distribution. However, simplified efficiencycalibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivityconcentration results. This study aims to develop an efficiency calibration optimization methodology toimprove the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulatorand a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object wasgenerated. Then, the sensitivity analysis of the efficiency calibration model was performed, and theefficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated withthe designed certification value. For the sensitivity assessment of the influencing factors of the efficiencycalibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size anddensity of the measured object. The standard deviation of the measurement efficiency as a function ofthe longitudinal size and density of the efficiency calibration model decreased with increasing energyregion. When using the optimized efficiency calibration model, the measurement efficiency using IUEwas improved compared to the measurement efficiency using ISOCS at the energy of 228Ac (911 keV) forthe nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between themeasured radiation concentration and the design value for each simulated subject measurement directionwas 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration andthe design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method,which was closer to the design value than the efficiency calibration method using ISOCS. In other words,the estimated radioactivity concentration using the optimized efficiency curve was similar to the designedradioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation,maintenance, and facility replacement of domestic byproduct generation facilities.
Abstract
In In-situ radioactivity measurement techniques, efficiency calibration models use predefinedmodels to simulate a sample’s geometry and radioactivity distribution. However, simplified efficiencycalibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivityconcentration results. This study aims to develop an efficiency calibration optimization methodology toimprove the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulatorand a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object wasgenerated. Then, the sensitivity analysis of the efficiency calibration model was performed, and theefficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated withthe designed certification value. For the sensitivity assessment of the influencing factors of the efficiencycalibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size anddensity of the measured object. The standard deviation of the measurement efficiency as a function ofthe longitudinal size and density of the efficiency calibration model decreased with increasing energyregion. When using the optimized efficiency calibration model, the measurement efficiency using IUEwas improved compared to the measurement efficiency using ISOCS at the energy of 228Ac (911 keV) forthe nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between themeasured radiation concentration and the design value for each simulated subject measurement directionwas 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration andthe design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method,which was closer to the design value than the efficiency calibration method using ISOCS. In other words,the estimated radioactivity concentration using the optimized efficiency curve was similar to the designedradioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation,maintenance, and facility replacement of domestic byproduct generation facilities.
참고문헌 (20)
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