Inventory of main maintenance interventions on nuclear power plant turbo-generators

Summary

The nominal design life of a generator is generally in the region of 30 years for turbo generators. Turbo-generators built
in the 70s have already reached the end of their planned life and many show various technical problems caused by aging. The purpose of this working group was to establish an inventory of main maintenance interventions such as main components replacement to extend the life of existing generators (e.g., stator bars rewinding, core restacking) or even their complete replacement.

An investigation was necessary to get a view of all main interventions done on the turbo-generators and duty cycles experienced before these interventions. This investigation tried to identify the reasons for interventions.
This report focuses on worldwide nuclear power plant main generators. Nuclear generation requests even higher level of availability, factor of safety and profitability. Utilities are always looking to optimise their maintenance cost, but also  have to minimise risk exposure to equipment failure. This report presents some durations between maintenance works. These durations are the results of utilities, manufacturers analysis and management decisions taken to try to reach the best compromise between risk and cost. In parallel with accurate technical analysis, these durations provide guidance to planning a long term maintenance program.

Additional informations

Authors

WORZYK, Lincoln, FORTOV

Keywords

rotating electrical machines, rotating machines, maintenance, nuclear power plant, turbo-generator