After servicing a thermohydraulic feedwater regulator, how long should it stabilize before returning to service?

The duration for a thermohydraulic feedwater regulator to stabilize before being returned to service is crucial for ensuring that the system is functioning properly and safely. The correct answer indicates a stabilization period of 60 minutes, which allows sufficient time for any thermal effects from servicing, such as cooling or heating, to dissipate.

During this period, the regulator can reach its operational temperature, ensuring that the components are in equilibrium and can respond properly to changes in the system. It's important to give the regulator time to stabilize because if it is put back into service too soon, it may not perform adequately, potentially leading to issues with water level control, improper feedwater flow, or even damage to the system.

Choosing a shorter period would not account for the thermal dynamics that could affect the regulator's operational characteristics, while longer periods may be unnecessarily conservative and could delay return to service. Hence, the 60-minute stabilization requirement strikes a balance, making it an industry-standard approach for reliable operation after maintenance.