May-June 2019 NPJ

Increasing MTBR Under Emergency Conditions By Faisal Salman, HydroAire. Faisal Salman Faisal Salman serves as director of nuclear services at HydroAire, a division of the Hydro Group of companies. Salman has been involved in aftermarket pump refurbishment and troubleshooting for over 30 years. He is a graduate of the University of Illinois with a Bachelor of Science degree in mechanical engineering. Background As the nuclear industry continues to adapt to new requirements under the Nuclear Promise, it is of key importance for utilities to strengthen existing safety protocols and execute efficiency improvements in day-to-day operations and maintenance to optimize overall costs. One such nuclear plant found themselves struggling in regards to a planned outage of a vertical service water pump, providing cooling water to safety- related heat exchangers in the power generation process. In this case, the operating pump was actively exhibiting performance issues and was reaching the end of its lifecycle, requiring their reserve unit be placed into service under xpedited conditions. The mportance of a Quality nspection The principal oal for the plant was to increase the Mean Time Between Repair (MTBR) of heir pumping system o optimize efficiency nd reduce costs. Unfortunately, upon nitial review of the eserve unit, it was identified that it had a history of poor performance issues under previous use. With this in mind, the nuclear plant chose to contact a trusted aftermarket pump service organization for disassembly, inspection, and root cause analysis to ensure a successful transition. A thorough inspection can help to identify issues that lead to recurring pump problems. Solutions can then be implemented to extend pump life and reduce long-term repair costs in future operation. Deep-rooted issues, if left unattended, often result in premature failure of components. An in-depth analysis can offer valuable insight for both the service organization and plant maintenance teams to discuss various options for not only repairing, but also optimizing the pump’s performance and overall lifecycle. By executing an engineering analysis, the service organization had isolated several critical issues which had contributed to the pump’s poor performance. It was noted that long-term damage to internal components, column pipes, and weld joints had been caused by less than optimal water chemistry. If left unattended, the consequences of this damage would lead to a higher risk of catastrophic failure. Routine wear had contributed to severe corrosion and erosion seen throughout the pump and its components. The edges of the impeller suction vanes were worn to a sharp, thin edge. The columns also experienced damage and were displaying thinned walls. Leakage from the pump’s flange joints was also noted which can decrease pressure and flow, negatively affecting the throughput. The operating pump was actively exhibiting performance issues and was reaching the end of its lifecycle, requiring their reserve unit be placed into service under expedited conditions. e I I g t t a i r 40 NuclearPlantJournal.com Nuclear Plant Journal, May-June 2019