Modernization of turbines in nuclear power plants

An ongoing goal in the power generation industry is to maximize the output of currently installed assets. This is most important at nuclear power plants due to the large capital investments that went into these plants and their base loaded service demands. Recent trends in the United States show a majority of nuclear plants are either obtaining, or are in the process of obtaining NRC approvals for operating license extensions and power uprates. This trend is evident in other countries as well. For example, all Swedish nuclear power plants are currently working on projects to extend their service life and maximize capacity through thermal uprate and turbine-generator upgrade with newest technology. The replacement of key components with improved ones is a means of optimizing the service life and availability of power plants. Economic advantages result from increased efficiency, higher output, shorter startup and shutdown times as well as reduced outage times and service costs. The rapid advances over recent years in the development of calculation programs enables adaptation of the latest blading technology to the special requirements imposed by steam turbine upgrading. This results in significant potential for generating additional output with the implementation of new technology, even without increased thermal power. In contrast to maintenance and investment in pure replacement or repair of a component with the primary goal of maintaining operability and reliability, the additional output gained by upgrading enables a return on investment to be reaped.