Question 123Steam Plants - QMED

The correct answer is D) exhaust to pressures above atmospheric pressure. Auxiliary turbine feed pumps typically do not require an external source of gland sealing steam because they exhaust to pressures above atmospheric pressure. This means the pressure at the pump's exhaust is high enough to provide the necessary sealing force, eliminating the need for additional gland sealing steam. The other options are incorrect because: A) operating at relatively low pressures does not inherently eliminate the need for gland sealing steam, B) the amount of axial thrust is not the primary factor, and C) the use of carbon packing rings is not the reason these pumps do not require external gland sealing steam.