Engineered Pump Assists Nuclear Plant Life Extension

Hayward Tyler custom designed a pump for the existing footprint whilst allowing a lower discharge pressure

A North American nuclear power plant needed to reduce their service water system pressure to allow them to continue to use buried pipework as part of their life extension plans. This required a change out of their service water pumps. These pumps are vertical, multistage turbine pumps. The replacement pumps were required to fit within the existing footprint and mate to the existing interfaces whiles hitting multiple performance requirements. Additionally, they were limited to a specified shut-off head to ensure the system didn’t exceed its maximum pressure. This required a custom pump design, including a customized hydraulic end.

Hayward Tyler engineers used existing nuclear pump design features as a base and customized a new hydraulic end. The pump curve was required to have a continuous rise towards shut-off (and a max shut-off value) while hitting multiple performance requirements and both full speed and slip adjusted motor speeds. Hayward Tyler’s hydraulic engineers were able to achieve these characteristics utilizing a two-stage design. The pump design was created using CFTurbo and then analyzed using PumpLinx. This included hydraulic performance, flow stability, NPSH and bearing loading (radial and axial) analyzes. The performance was validated during factory testing at Hayward Tyler’s facility.

These pumps were classified as Seismic Class 1 and “Safety-related” requiring to be operated during normal and emergency shutdown, post-accident shutdown, hot stand-by. refueling and other special events. Hayward Tyler engineers performed all necessary ASME B&PV Section VIII code calculations including a full seismic analysis validating the pump design. The existing installed pumps used two different motor manufactures. Hayward Tyler engineers performed the new seismic analysis, considering either motor allowing site to have interchangeability of the motors.

Hayward Tyler’s technical expertise and engineering capabilities allowed the design of a custom engineering, vertical turbine pump to extend the operating life of the station. This supports carbon-free energy to power the equivalent of nearly 1 million homes for an additional 20 years.