Development Of Non-destructive Detection Device For Gd₂O₃ Content In Nuclear Fuel Rods

Compared with developed foreign countries,China's research and application of gadolinium content detection in nuclear fuel rods are lagged behind.With the rapid development of nuclear power plant,it is quite urgent to solve this technique issue,which is also of great significance in engineering.In this paper,studies and analysis on gadolinium(and its isotopes)detection,non-destructive detection,eddy current detection were carried out.Based on eddy current non-destructive detection and permanent magnetic field saturation techniques,the overall solution of automatic detection of gadolinium content in nuclear fuel rods was determined,the required platform was built in laboratory environment for simulation,the particular nuclear fuel rods required by simulation and the standard ones were designed and developed.C++ language was selected to build the detection system,the non-destructive detection device for Gd2O3 content was developed,its performance indexes were tested and compared with those of manual operation and judgment.Additionally,the influences from zirconium alloy cladding tubes and ferromagnetic material on detection signals were analyzed as emphases,and the solution was provided.Verified by experiments,the method to eliminate those influences could meet practical needs.The non-destruction device developed in this paper could detect the Gd content of single fuel block,and the uncertainty of mass could be limited within ±1%,the reliability was over 95%,the accuracy of averages was better than 2%,and the detection speed is faster than 1m/min.As expected,automatic feeding and unloading,detecting and sorting were all achieved.