GRAPHALLOY® Bushings Run for 8+ Years in Nuclear Heater Drain Pump

GRAPHALLOY® Bushings Run for 8+ Years in Nuclear Heater Drain Pump
In a power plant, the heater drain pump sends the drain water directly back into the feed water system thus increasing the efficiency of the power generation, so reliability of the heater drain pump is important.
A pump repair shop had replaced the original bearings in a heater drain pump with GRAPHALLOY® bushings 8 years earlier to increase MTBR in the pump.
It was time for a complete overhaul of the pump and this gave them a chance to see how the GRAPHALLOY® bushings were doing.
Upon inspecting the existing self-lubricating GRAPHALLOY® bushings, they found that after eight years of service the running clearance had increased by only .003″ to .010″ from the original specifications. Since they were doing a complete overhaul, they decided to replace the bushings. There was a slight increase in vibration, but the bushings were still working well.
The bushings are Nickel Grade GRAPHALLOY® and are used as the suction bell bushing and intermediate bearings.
This is a pump that sees constant use and is generally rebuilt every 5 to 8 years. After this rebuild, the pump was put back into service and over 8 years later is still running well. The bushings are intended to be the sacrificial wear part and GRAPHALLOY® has proven itself a great option for this application.