When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to __________.

Correct Answer: Option A — seal the casing during periods of low casing pressure

In USCG Steam Plants (Boilers & Turbines), regarding 'When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to', the verified engineering fact is: 'seal the casing during periods of low casing pressure'.