Stress Analysis and Evaluation of Mussel Trap for Nuclear Power Plant

The mussel trap is an important component used in nuclear power plant (NPP). The component belongs to RCC-P nuclear safety class 3, code and class RCC-M3, seismic category 1F and Q.A category Q2. The mussel trap is made up of screen, half-sphere, main flanges, nozzles, rotors, bolts, motor, supports and so on. The loads requirements in design conditions contain both internal loads and external loads. The loads have dead weight, pressure, nozzles loads and seismic loads. In this paper, the finite element model of the mussel trap is built with shell element using the structural analysis software-ANSYS. The stress analysis is based on linear elastic static analysis. The subspace iteration method is used for the modal analysis of the mussel trap. The static analysis is used for the mussel trap under deadweight, pressure and nozzle loads. At last, an evaluation of all loads combinations stresses against the respective stress limit for plate- and shell-type components and linear type systems is done according to the requirements of relative criteria specified in RCC-M. The evaluation result demonstrates that all loads combinations stresses of the mussel trap structure meet the requirements of RCC-M.