The research objective is an improved life prediction method for fatigue crack growth at mixing points between hot and cold water in pipe systems and control rods found in nuclear power plants. The developed method can be used to determine fatigue risk at the mixing points and to establish inspection intervals and service programs. Further, it will supply data for decision on repair or replenishment of pipe joints.
Calculated temperature and pressure data from a CFD simulation will be used as load input in a corresponding FEM model. The goal of the FEM model is to analyze the magnitude of thermal stresses, including their cycles and sequences, which occurs at the mixing point due to the temperature changes and pressure load. The FEM simulation will give indication on the major cause of failure in components with mixing points, i.e. whether it is due to large scale yielding load conditions or environmental conditions.
The computational results will be validated against experiments run at KTH.