Question 711Steam Plants - Assistant Engineer

The correct answer is B) astern throttle valve. When starting up a main propulsion turbine, steam should first be admitted to the rotor through the astern throttle valve. This allows the turbine to be gradually warmed up and brought up to operating speed in the astern direction before switching to the ahead direction. Admitting steam through the ahead throttle valve could potentially cause thermal damage to the turbine components if the rotor is not properly warmed up. The other options are incorrect because the ahead throttle valve (A) is used to admit steam for ahead operation, the LP turbine bleed valve (C) and HP turbine bleed valve (D) are used for other purposes and not for the initial warm-up of the turbine.