Plant uprate: an economic evaluation and implementation approach

There is a major trend within the utility industry toward increasing the availability and generating capacity of existing units that is caused by the increasing lead times, capital costs, and construction costs of new generating facilities. Increasing the electrical output of existing units is a less capital-intensive means to aid in meeting a utility's future load growth requirements. A major component of the Virginia Power plant improvement program is core thermal power uprating of its nuclear units. Nuclear plant upratings are of growing utility industry interest because of the large expected economic benefits. However, there are concerns regarding the impact on a plant's current operating license. The potential for core upratings was generally recognized by utilities and vendors by incorporating additional capacity in the original plant design. This was done with the understanding that increased thermal power ratings could be implemented in the future based on demonstrated levels of safety and operability. Safety-related features of a unit have been commonly designed for a thermal power approx.5% above the original licensed rating. This creates the potential to uprate the unit's electrical capacity with only minor or no modifications to the plant. This paper presents Virginia Power's experiences regarding the benefits of nuclear plant uprating, outline their licensing approach, and describes current plans for implementation