EXTENDING THE INSPECTION INTERVAL OF CRITICAL POWER PLANT EQUIPMENT; STEAM TURBINE ROTORS, BLADES, PIPING, BOILERS, ETC.

摘要

When deregulation of the utility industry becomes a reality in the near future, power plant managers and engineers will face a completely changed business climate. Surviving in a competitive business world will require a dramatic alteration in the way most utility power plants are maintained and upgraded, and in their budget planning. Some utilities have already started to reduce overhead maintenance costs. One approach to cost savings is to extend the outage and/or inspection intervals for major power plant components; particularly those that require considerable time and costs to prepare, inspect, and evaluate. The steam turbine unit is a plant component where an extended inspection interval could result in considerable cost savings provided it does not jeopardize the integrity or safely of the power plant. Components that lend themselves to extended outage/inspection intervals include the steam turbine rotor and blades. The outage interval of other turbine components, piping systems, boilers, and balance-of-plant components can also be extended using the following steps: 1) increased inspection sensitivity, 2) detailed knowledge of the existing condition of the material of the component, 3) detailed information on the environment (stress, temperature, etc.), 4) generic background information on failures and repairs of this and similar units, 5) and special remote inspections monitoring and/or partial disassembly to allow periodic evaluation of a component with minimum costs. The above information can be combined into a mathematical model that can be used to predict optimum inspection intervals as a function of costs and risk. Examples of recently completed projects in the above areas are presented.