During which operation do the module valves need to remain open?

The module valves need to remain open during both fueling and defueling operations to ensure proper flow of fuel through the system. This allows for an uninterrupted transfer of fuel into or out of the tanks, maintaining efficiency and safety during these critical operations. When the valves are open, they facilitate the movement of fuel, allowing operators to effectively manage fuel levels and ensure that the process is conducted safely and without delays.

In fueling operations, keeping the valves open is essential for the timely delivery of fuel into the storage tanks, while in defueling, it is equally important to allow the swift removal of fuel. Closing the valves during these operations could lead to blockages, potential spills, or create pressure imbalances, which can be hazardous. Therefore, maintaining the module valves in an open position during both fueling and defueling operations is crucial for effective and safe fuel management.