Development of Online Sipping Detection Device Based on β-γ Coincidence Method

The fuel cladding tubes damage often occurs during the operation of the reactor. When a fuel assembly is damaged, the power plant usually performs a sipping test on each fuel assembly using an online sipping device during the re-fueling process, and determines whether the tested assembly is damaged. However, due to the influence of the strong radiation in the island, misjudgment and missed judgment may occur in the detection results by detecting single β or γ particle. In this paper, an online-sipping detection device based on β-γ coincidence measurement technology is designed, which contains β and γ particle detectors, and a β-γ coincidence detection channel. It combines existing β and γ damage judgment technologies and adds the results based on β-γ coincidence judgments. The results of the applications show that the device background counting rate can reach 0.04 s^–1 and the Minimum Detectable Activity (MDA) of ¹³³Xe can reach 23.7 Bq under the environmental radiation in the nuclear island. The detection sensitivity is better than that of a single β or γ particle detection mode. The application of the three judgment modes significantly enhances the reliability of damage determination results. This device can replace the existing online sipping detection device of single particle detection mode and be applied to the nuclear power site to carry out relevant detection work.