Condenser performance impact on plant operations and component life cycle

A review highlighting the importance of surface condenser performance to achieving nuclear power plant design capacity and maintaining expected component life cycle is presented. Problems associated with identifying the cause of unexplained continuous condenser performance indications such as excessive operating pressure, high dissolved oxygen and low tube heat transfer coefficient are discussed . It will be shown, from an historic view point, that incomplete knowledge of heat transfer conditions within the condenser and the lack of shell side condenser measurement capability were responsible for these problems. Over the past four years, however, measurement data from a relatively new instrument, employed over the past ten years for condenser monitoring, has been used to aid development of a comprehensive description and model of condenser heat transfer throughout the condenser's tube bundle. The model shows how design has influence over measurement of performance related parameters. As a result, condenser design and fabrication features leading to performance loss have been identified by this model and some of these will be presented. The new instrument will be reviewed in detail to show its utility. Results of the comprehensive model and theory will be presented to permit some understanding of the benefits that may be derived from a service leading to removal of condenser degrading design features or for the design of new condensers devoid of these defects. Changes can result in significant lowering of condenser pressure, providing improved power generation capacity between 0.5 to 2% and a reduction in dissolved oxygen to negligible levels. (author)