Managed Operation and Repair of a Deteriorating Large Diameter Pipeline

Since 1986, Brandon Shores Generating Station has successfully managed a recurring maintenance problem with the buried prestressed concrete cylinder pipe (PCCP) of its circulating water system. It is the intent of this paper to provide a history of the plant`s approach to safely operating and maintaining the deteriorating pipe of this system. This paper will briefly discuss the results of failure analysis performed on the ruptured pipe. Findings of engineering studies addressing the structural integrity of the remaining pipeline will be discussed. The inspection methodology used at Brandon Shores to periodically assess the pipe will be described. Several methods of pipe repair, both external and internal will be detailed. Particular focus will be placed on an internal repair design successfully implemented on two pipe sections during a 1993 plant outage. This internal repair resulted in no loss of hydraulic section, and was erected in-place using conventional materials which were entirely transported through 36 inch manholes. The pipeline was placed back in service and has performed satisfactorily to date.