Simulation of Detection Efficiency of High Integrity Container Gamma Scanning Device for Nuclear Power Plant Based on CZT Detector

Abstract

High Integrity Container (HIC) for nuclear power plant is an advanced waste reconditioning Container specially designed and manufactured. It has the characteristics of High strength, good sealing, strong chemical stability and thermal stability. It can be used to load a variety of Low and Intermediate Level radioactive wastes that have not been cured or fixed, such as dehydrated mud and evaporation residues, Waste resins and Waste water filtration cores. According to relevant national standards and nuclear power plant radioactive waste management regulations, it is necessary to measure the type of radionuclide and radioactive level of waste barrels. The sizes of HIC barrels are DI, DII and DIII, with volumes ranging from 0.42 m3 to 3.44 m3. There are various types of waste in the bucket, and the waste density is not less than 0.25 g·cm−3; The main material of HIC barrel is high density crosslinked polyethylene, which has poor shielding effect on γ-rays, resulting in high dose rate level on the surface of the barrel. Therefore, the existing γ scanning device for 200 L/400 L metal waste drums in nuclear power plants cannot meet the measurement requirements of HIC drums, and it is necessary to develop a special γ scanning device for HIC drums. In this study, Cadmium Zinc Telluride (CZT) semiconductor was used as the main detector to simulate the detection efficiency under different HIC barrel sizes, different waste density, different detection distances and different collimating opening diameters. The simulation results show that the CZT detector can be used for gamma scanning measurement of HIC drums, especially HIC drums with high dose rate, under the condition of proper shielding collimation and detection distance.