核电厂一回路典型核素探测效率标定方法研究

Research on Calibration Method of Typical Nuclide Detection Efficiency of Primary Circuit in Nuclear Power Plants

核电厂一回路典型放射性核素探测效率标定实验对核电厂最终一回路泄漏率的确定和海洋环境中放射性核素监测具有重要作用。将18F作为监测核电厂一回路压力边界的泄漏率的理想核素,采用实验与MCNP模拟两种方法完成了18F的探测效率标定,表明在一定区间内,随着18F源与探测器探头间距离平方倒数的增加,探测器对18F的探测效率逐渐增加。通过实验与模拟两种方法,证明18F的探测效率符合平方反比定律,实验结论成立。根据实验数据,得出18F的探测效率经验公式。

The calibration experiment of typical primary radionuclide detection efficiency in a nuclear power plant plays an important role in determining the final primary leakage rate of nuclear power plants and monitoring radionuclides in marine environment.This paper takes 18F as the ideal nuclide to monitor the leakage rate of primary pressure boundary in nuclear power plants,and uses experiment and MCNP simulation to accomplish the detection efficiency calibration of 18F,indicating that within a certain interval,with the increase of the square reciprocal of the distance between the 18F source and the probe,the detector’s detection efficiency of 18F increases gradually.Through experiments and simulations,it is proved that the detection efficiency of 18F conforms to the inverse-square law,hence the valid experimental conclusion.Based on the experimental data,the empirical formula of detection efficiency of 18F is obtained.