A Theoretical Investigation of Calibration Methods for Radwaste Radioactivity Detection Systems

摘要

The three-dimensional point-kernel computer code QAD-CGGP is used to calibrate the Q2 detection system proposed as the detection system for measuring uncollided photon fluence rate from low-level radwaste at the Kuosheng and Maanshan Nuclear Power Plants in Taiwan. The calibration drum in the Q2 detection system was originally divided into seven concentric regions of equal volume This was replaced by seven thin source tubes to eliminate storage problems associated with the uniformly distributed sources for each concentric region, and was found that the position of the source tube in the outermost region of the drum can significantly affect calibration accuracy This phenomenon becomes more serious for highly attenuated radwaste such as sand Althoughproper adjustment of the source tube position in the outermost region improves calibration accuracy, especially for highly attenuated radwaste, the new source tube position is too close to the surface of the drum and can increase calibration inaccuracywhen the materials in the source tube and in the rest of the drum are different We propose an improved metho'd that divides the calibration drum into three region sources Appropriate arrangement of the source tube positions within these regions' was found to improve calibration accuracy simplify calibration procedures, and save calibration time.