上海科技大学知识管理系统

The fuel rod cladding serves as the first safety barrier within a nuclear power plant. It is essential to measure and evaluate the thickness of oxide film on the fuel rod cladding with micrometer level precision to ensure the operation safety of the nuclear power plant. In recent years, fuel rods with metal coating are utilized to enhance the mechanic characteristics of the rods, resulting in further challenge for the measurement. This paper presents a novel swept-frequency eddy current testing (ECT) method for the oxide film thickness measurement, which suppresses the interference of the coating parameters by a multi-parameter separation algorithm. A finite element method model is established to study the effect of the conductivity of the cladding and thickness of the coating on the oxide film thickness measurement. Then, a multi-parameter separation algorithm is developed to process the simulation data. It is demonstrated that the calculation error of the algorithm is less than 0.4 mu m with varying material parameters. In addition, a prototype probe is developed and tested. The experimental results show that with different thicknesses of metal coatings, the proposed method can measure the oxide film thickness on fuel rod cladding with error less than 3 mu m, which can satisfy the field application.