Simulation results of the online tritiated water measurement system

Currently, the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants, which leads to the continuous production of radioactive waste during measurement. In addition, the real-time activity information of tritiated water cannot be obtained. To solve this problem, herein we present an online tritiated water measurement method based on plastic scintillators that used the optical transport process in the Geant 4 software toolkit to build a model of plastic scintillation detection for tritiated water. Through simulation, the basic geometric dimensions of the detector were determined. In this dimension, using one detector to measure for 3 h, when the tritiated water activity was 100 Bq/L, its resolution was 16% (16 Bq/L). In addition, calculations were performed for the presence of other background signals to obtain the minimum detectable concentration.