What action must be taken for high pressure feedwater turbine control valves?

For high pressure feedwater turbine control valves, the action of fully closing them during low pressure conditions is essential for maintaining the safe and efficient operation of the turbine system. When operating under low pressure, having the control valves fully closed prevents the backflow of water or steam that could lead to damage or inefficient turbine performance. This measure helps in ensuring that the system operates within its designed pressure parameters, safeguarding against potential mechanical failure.

In operational scenarios, the turbine requires a specific pressure range to function correctly. If the feedwater is under low pressure, keeping the control valves closed allows for better control and regulation of water flow into the system, preventing issues such as water hammer or inadequate cooling, which might otherwise occur if valves were inadvertently left open.

Monitoring only for leakage or adjusting them weekly may not adequately address the critical performance needs of the turbine under varying pressure conditions. Continuous opening of the valves disregards the possible fluctuations in pressure that can affect the entire system's integrity. Therefore, ensuring the valves are fully closed when low pressure is detected is a proactive approach to maintenance and safety in feedwater systems.