Regarding steam production, which statement is true?

• A. In PWRs, boiling occurs in steam generators, not in the reactor core; moisture separators are at the top of the steam generators.
• B. In PWRs, boiling occurs in the reactor core; moisture separators and dryers are at the bottom of the reactor.
• C. In BWRs, steam is produced in external steam drums separate from the reactor; moisture separators are irrelevant.
• D. In BWRs, there is no steam production; turbines run on electric motors.

Answer: (A)

In this topic, the way steam is produced depends on the reactor design. In a PWR, the core is kept under high pressure so the water in the core does not boil; instead, the heat from the core is transferred to a separate secondary loop through steam generators, where the secondary water boils to make steam. That steam then needs to be cleaned of moisture before it reaches the turbine, so moisture separators and dryers are placed where the steam separates from water at the top of the steam generator region. This arrangement means boiling happens in the steam generators, not in the reactor core, and the moisture separation happens near the top of the steam-generating area.

Why the other descriptions don’t fit: boiling in the reactor core isn’t how a PWR operates, since the core water is kept under high pressure to stay liquid. In a BWR, steam is produced directly in the reactor vessel itself, not in external steam drums away from the reactor, and moisture separators are relevant because the steam going to the turbine must be dry. Also, BWRs do produce steam to drive turbines, not electric motors, and there is no scenario where “no steam production” occurs.