Analysis of the axial fitting clearance between the fuel rod and the end seat in CIADS

摘要

The fuel assembly is key structure in China Initiative Accelerator Driven System,and the axial fitting clearance(AFC) for the fuel assembly design is an essential subject of study.In this paper,different methods are used to calculate critical stress in cylindrical shells.Because the thermal expansion of fuel assembly outer tube is larger than that of the cladding of fuel rod,enough space should be reserved between the upper end plug and upper seat slot.The collapse critical compressive stress of the cladding is obtained numerically through ANSYS simulation calculation.The AFC range between the fuel rod cladding and the end seat due to the displacement of thermal expansion is given by the theoretical formulas and ANSYS buckling analysis.These provide a reference for the AFC design of the reactor fuel assembly.