Detection Efficiency Fitting Method Research by Γ-Ray Spectroscopy for Quantitative Nuclear Material Holdup

The term “holdup” refers to nuclear material that has been deposited in the processing facility’s equipment, containers, pipelines, etc. Nuclear material control and accounting require the monitoring of nuclear material holdup in process. Holdup is useful for indicating the state of facility operations, critical radiation safety status, and so on. It is more difficulty to quantitative analyzed nuclear material holdup by destructive analysis method. So non-destructive analysis (NDA) technology for in-situ and on-line measurement satisfied to the actual situation are the most recommended nominator for holdup quantitative analysis. In order to get the detection efficiency of γ-ray spectroscopy for quantitative nuclear material holdup. The intrinsic detection efficiency, geometric detection efficiency, and self-absorption attenuation correction methods are researched in this paper by combining Monte Carlo simulation and experiment. Three-dimensional and the least square fitting methods, and the distribution of the nuclear material holdup in the simulation pipeline system of nuclear facilities’ production line is simplified. Resulted to the experiment, the deviation between declared and the measured value is less than 30%. Compared with the requirements of national nuclear safeguards supervision and the needs of facility operation, the detection efficiency fitting method research by γ-ray spectroscopy for quantitative nuclear material holdup is achievable. It also can be widely used to provide relevant data in radiation dose monitoring, decommissioning source item investigation, and so on.