In a Pressurized Water Reactor (PWR), what happens to heat during steam generation in the secondary loop?

• A. The primary water stays separate from the secondary water while steam is generated.
• B. The primary water mixes with the secondary water during steam generation.
• C. The primary water is removed from the system.
• D. Steam is produced without heat exchange.

Answer: (A)

In a PWR, steam generation on the secondary side happens through a heat exchanger, not by mixing the fluids. The hot, pressurized primary coolant flows through the steam generator tubes and transfers its heat to the water in the secondary loop. The primary water stays separate inside the reactor coolant system, while the secondary water absorbs that heat, boils, and becomes steam to drive the turbines. Keeping the loops separate prevents radioactive contamination of the secondary side and allows efficient steam production via heat transfer, rather than mixing.