At what point does the MFP lube oil become a backup system for HP header pressure?

The correct choice is linked to the operational thresholds of the motor-driven feedwater pumps (MFP) in the context of maintaining high pressure in the HP (High-Pressure) header system. The lube oil system is designed to lubricate the moving parts of the MFP, ensuring efficient operation and preventing wear. In cases where the primary hydraulic pressure could fail or drop, the lube oil system serves as a reliable backup.

When the lube oil pressure reaches the specified level, in this case, 175 psi, it indicates that the hydraulic system can sustain adequate performance while reducing the risks associated with lower pressures that can lead to equipment damage or operational failure. This threshold serves as a critical safety mechanism, providing functionality and security for the HP header system, ensuring it maintains the necessary pressure needed for optimal performance of the boiler system.

Other pressure levels listed do not trigger the same level of reliability in terms of backup for HP header pressure. Therefore, understanding the specific pressure threshold, such as the significance of 175 psi for the lube oil in relation to equipment functionality, is essential for the safe and efficient operation of water auxiliary equipment in power generation systems.