Question 346Steam Plants - 1st Asst/Chief

The correct answer is D) astern throttle valve. When properly lining up the main propulsion turbine for warm-up, steam should first be admitted to the rotor through the astern throttle valve. This allows the turbine rotor to gradually warm up and expand, preventing thermal stresses that could damage the turbine. The astern throttle valve controls the flow of steam to the astern section of the turbine, which is necessary for the initial warm-up process. The other answer choices are incorrect because the HP turbine bleed valve, ahead throttle valve, and LP turbine bleed valve are not involved in the initial warm-up process. These valves serve other functions related to the operation of the turbine, but do not handle the initial admission of steam during the warm-up phase.