What is the primary function of steam in nuclear reactors?

• A. To cool the reactor.
• B. To lubricate turbine components.
• C. To heat the coolant to the boiling point.
• D. To spin the turbine and produce electricity.

Answer: (D)

Steam's job is to take the reactor's heat and turn it into motion that drives the turbine, which then powers the generator to produce electricity. In most plants, heat is first transferred to a secondary water loop, where the water boils into steam. That steam expands through the turbine, transferring energy as mechanical rotation. Afterward, the steam is condensed back into water and recirculated. The reactor itself is cooled by its primary coolant loop, not by the steam used for power generation, and lubrication of turbine components isn’t provided by steam. Also, boiling is controlled in the secondary loop, with the primary loop kept under pressure to prevent boiling inside the reactor. This shows the primary purpose of the steam: convert thermal energy into mechanical energy to drive electricity production.