In a nuclear reactor, what is the primary purpose of the cooling water?

• A. To cool the reactor and prevent overheating
• B. To convert heat directly into electrical energy
• C. To dilute the reactor fuel
• D. To remove heat produced by fission and often generate steam to drive turbines

Answer: (D)

The cooling water is there to remove the heat produced by fission from the reactor. If this heat isn’t carried away, the fuel could overheat and be damaged. In many reactor designs, that absorbed heat is then used to generate steam in a secondary loop, and the steam drives turbines to produce electricity. So the best description includes both removing heat and providing the steam that powers the turbines. The other ideas miss either the heat-removal role alone or how electricity is actually generated from that heat.