Which component is adjustable and can stop a reaction?

Which component is adjustable and can stop a reaction?

• A. Coolant
• B. Regulator Rods
• C. Control Rods
• D. Moderator

Answer: (C)

Stopping a nuclear chain reaction relies on removing neutrons from causing further fission. Control rods are made of neutron-absorbing materials, and by moving them in or out, you change how many neutrons are captured. Inserting the rods deeper absorbs more neutrons, reducing the neutron population and slowing the reaction; inserting them fully can halt the chain reaction altogether. Other components serve different roles—moderators slow neutrons to sustain fission, coolant removes heat, and regulator rods adjust reactivity but aren’t the primary mechanism for stopping the reaction.

Stopping a nuclear chain reaction relies on removing neutrons from causing further fission. Control rods are made of neutron-absorbing materials, and by moving them in or out, you change how many neutrons are captured. Inserting the rods deeper absorbs more neutrons, reducing the neutron population and slowing the reaction; inserting them fully can halt the chain reaction altogether. Other components serve different roles—moderators slow neutrons to sustain fission, coolant removes heat, and regulator rods adjust reactivity but aren’t the primary mechanism for stopping the reaction.