Steam Turbine Risk Assessment Project: Inspection and Overhauls Optimization of Steam Turbines, 1997 Engineering Conference Proceedings

There is a trend in the pulp and paper industry, as well as in other heavy industries, to increase the time between overhauls of machinery, particularly steam turbines. The primary driving force behind this tendency is the desire to reduce direct overhauling and inspection costs. The basis for justifying additional overhaul and inspection work is sometimes expressed by machinery engineers as a “risk of failure.” This risk is not easily quantified and may not be understood by managers responsible for these budgets. The Steam Turbine Risk Assessment Project (STRAP) was initiated to develop a methodology and model for addressing the optimization of overhauls by identifying and quantifying the “risk of failure” associated with maintenance, operation, and engineering practices applied to steam turbines. The process is an adaptation of the ASME Risk-Based Inspection Guidelines and has been used previously on a project for utility steam turbine/generators. This paper details development of the STRAP model, demonstrates the application of this model in evaluating a turbine, and displays the results achieved through testing of the analysis. The STRAP model is incorporated into a computer program that allows “what if’ scenarios for individual turbines to be evaluated on a cost-risk-benefit basis. These results are then used to optimize the overhaul and inspection process.