Post-Irradiation Dimension Examination of Tubular Fuel Assembly

This paper mainly introduces the post-irradiation dimension measurement contents, methods and results of the new tubular fuel assembly, and makes a preliminary evaluation of the measurement results. The results show that the total length of the fuel assembly is slightly increased compared with that before irradiation, and the average growth rate is 0.71 mm. There is no change in degree of bending and twisting after irradiation. The maximum growth of margin distance is 0.17 mm and minimum growth is 0.07 mm. The water gap of each layer showes a decreasing trend, and the maximum decrease is 0.33 mm. The maximum outer diameter of the fuel pipe increases is 0.13 mm, and the maximum inner diameter of the fuel pipe decreases is 0.20 mm.