Identify electric-output losses at PWR nuclear plants

Licensing difficulties and reduced electrical-growth demands of recent years have contributed strongly to the static state of the nuclear industry. At the same time, a substantial electricity growth for the next five years-up to 3.4%/year-is forseen. One method to cope with this demand/supply mismatch is to improve the heat rate of existing plants. A 1% heat rate improvement across-the-board for all nuclear plants, for example, will compensate for more than 5% of the yearly electricity-demand growth. Techniques used to monitor the heat rate and diagnose the causes of degradation vary greatly from utility to utility. The simplest program, which is still being used by utilities with a small engineering staff, is to periodically monitor the heat rate or electrical output. If the heat rate goes beyond a present value, an engineer is sent to investigate. Unfortunately, the findings are often more qualitative than quantitative. For a utility having a dedicated performance engineer or group, the practice for heat-rate monitoring and diagnosis is more elaborate. It often comprises two subprograms-data trending and heat-rate analysis. Data trending means that a selected group of measured data related to plant heat rate is taken periodically and their trends are closely monitored. A heat-rate analysis, usually in accordance with one of the heat-rate codes, is performed to identify the causes of the degradation and to optimize the fix. The analysis requires a trial-and-error process to pinpoint the causes