Performance Evaluation of Feedwater Heaters for Nuclear Plants Under Normal and Abnormal Conditions

This paper discusses the performance of feedwater heaters for nuclear plants under normal and abnormal conditions. Normal conditions are defined as all heaters operating in their design configuration with no plugged or leaking tubes. Abnormal conditions refer to plugged tubes, leaking tubes, heaters out of service, extraneous flows, etc. In recent years, with several nuclear plants uprating or planning to uprate, heaters are operating or will be operating at or very close to their thermal design levels. Also, many heaters are being subject to abnormal conditions. All these result in both thermal and hydraulic overload and premature as well as accelerated failure of several heaters. The paper examines the performance parameters for heaters under normal and abnormal conditions and the use of performance modeling tools in evaluating performance. Recommendations are provided for monitoring the performance of heaters under normal and abnormal conditions.