What occurs within the tubes of the device labeled "23" shown in the illustration? Illustration MO-0111

Correct Answer: Option A — The feedwater flowing through the inside of the tubes is being heated by the jacket water on the outside of the tubes.

Jacket water flows through the shell side while feedwater passes inside the tube bundle, absorbing thermal energy from the high-temperature engine cooling water to preheat boiler feed or freshwater generator inputs.