Repairing Feedwater Heater Tubes Using Explosively Welded and Brazed Sleeves

Failures in either the desuperheating zone or drainscooling zone may occur during the long term operation of high pressure feedwater heaters. When the number of failures gets high, the risk of the loss of generation or availability often requires replacement of a feedwater heater. Often, it is important to maintain a reasonably high level of heater availability while the replacement is planned and procured. It is prudent to minimize the potential for a catastrophic set of tube failures which could result in the potential for a turbine water induction incident or an extended repair outage. In such cases, a repair strategy that includes the use of tube sleeves, also referred to as liners, can provide a high level of leak tightness and can provide the operating margin and reliability to help get a heater through a critical operating period, such as a summer high load demand. Installing a sleeve, which is bonded to the tube on both ends, can provide this level of integrity.