APPROACH TO RESIDUAL LIFE ASSESSMENT OF LARGE STEAM-TURBINE COMPONENTS

Ansaldo has manufactured and installed in Italy and all over the world, since 1909, medium and large steam turbines under its own design and various licence agreements, such as General Electric, Westinghouse, and, more recently, ABB. Since 1986 residual life assessment research programs have been implemented with a big effort, and a special approach to residual life assessment has been defined with our main customer, the ENEL Company, for the activity to be carried out in order to get the optimum balance between safety and cost consideration. The paper will illustrate this approach as well as the techniques developed for residual life investigations. In the paper are presented examples of the documentation for data acquisition, examples of the application of investigation techniques such as computer echotomography, boresonic and material sampling on rotors, and finite element analysis on critical main steam valves.