Research On Enrichment Detector Of Nuclear Fuel Rod Based On Cadmium Zinc Telluride

In recent years,with the rapid development of nuclear power plants,the safety of nuclear power plants has becoming the focus of public attention.In order to ensure the safe operation of the nuclear power plant,we need to detect the 100% enrichment of the nuclear fuel rod,the main fuel component of the nuclear power plant.CZT detectors,as a new type of semiconductor detectors,is widely used in nuclear radiation energy spectrum detection,medical imaging detection and space cosmic ray detection due to its good energy resolution and detection efficiency.In order to explore the possibility of its application in nuclear fuel rod enrichment detection,this thesis proposes to design a nuclear fuel rod enrichment detector based on CZT.The main contents and achievements are as follows:(1)Geant4 software was used to simulate the absorption of gamma rays by different semiconductor materials,and the size and position of CZT in the structure of CZT detector were simulated to affect the absorption of delayed gamma rays from nuclear fuel rods.The simulation results showed that CZT crystals with a energy of5 mm below 200 ke V had good absorption characteristics.When CZT crystal is close to radioactive source,the detector with triangular structure has good detection efficiency for gamma ray.(2)According to the simulation results,combined with CZT crystal growth characteristics,electrode preparation characteristics and CZT detector leakage current under different conditions,a CZT detector suitable for nuclear fuel rod detection structure is designed.According to the characteristics of CZT detector output step pulse signal,its analog signal readout circuit is designed.(3)The output waveforms of planar,hemispherical and pixel CZT detectors are tested experimentally under the action of gamma rays.The pixel type CZT detector for nuclear fuel rods was fabricated and energy spectrum test was carried out.The pixel detector has good portability and high detection efficiency.However,due to the limitation of the test environment and the simplicity of the readout circuit,the energy resolution of low-energy gamma rays has not achieved the desired effect,and the system integration and noise reduction need to be improved.