Which of the following is NOT a core component in a reactor that affects neutronic properties?

Control panels are not considered a core component of a nuclear reactor that directly affects neutronic properties. The core components that influence neutronic behavior include fuel elements, coolant, and moderator, all of which play integral roles in the nuclear fission process.

Fuel elements contain fissile material, which undergoes fission and releases neutrons. The composition and arrangement of these elements significantly influence the reactor's reactivity.

The coolant, while primarily responsible for transferring heat away from the reactor core, also plays a role in moderating the neutrons, especially in certain reactor designs (for instance, in water-cooled reactors where water serves both as coolant and moderator).

The moderator is a specific material that slows down the fast neutrons produced by fission. By slowing them down, the moderator increases the likelihood that these neutrons will induce further fission reactions, thus affecting the overall reactivity of the core.

In summary, while fuel, coolant, and moderator interact with neutrons and affect their behavior in the reactor, control panels are primarily used for monitoring and managing the reactor rather than influencing how neutrons interact within the core. Hence, they do not directly impact the neutronic properties of the reactor.