Which of the following is a function of in-core neutron sensors?

• A. Measure turbine rotor speed
• B. Monitor ambient gamma rate outside core
• C. Confirm calculated core performance
• D. Adjust reactor coolant flow

Answer: (C)

In-core neutron sensors are used to verify how the reactor core is actually behaving by providing real-time neutron flux measurements inside the core. This real data is compared to the predictions from the reactor physics calculations that define how the core should perform under the current conditions. When the measured flux matches the calculated core performance, operators gain confidence that the models, power distribution, and safety margins are accurate and that the core is operating as expected. These sensors aren’t intended to measure turbine speed, ambient gamma levels outside the core, or to directly control coolant flow; their role is specifically to confirm that the calculated core performance reflects reality inside the reactor.