On the possibility of degradation of a control valve of 200 MW unit during start up

Elements and structures in power plants, especially in combined cycle or supercritical power plants are frequently subjected to serve high thermal and mechanical stresses in the condition of the stress corrosion damage. Repeated loading due to start up and shout down or normal operation cycles may lead to corrosion-fatigue failure. Complex states of deformation are common within those elements since different sources of cycling loading may differ in phase and frequency. In the case of high operating temperatures, the irreversible creep deformation may add to the complexity of problem. In the article this problem has been analyzed using 3D Computational Fluid Dynamics (CFD) and 3D Computational Structural Mechanics (FEM).