The control rod that compensates for changes in reactivity is the

The control rod that compensates for changes in reactivity is the

• A. Safety rod
• B. Containment system
• C. Absorption rod
• D. Shim rod

Answer: (D)

Shim rods provide fine, small adjustments to reactivity to offset the changes that occur during operation, such as fuel burn-up and temperature shifts. They are designed to be inserted or withdrawn a little at a time to keep the reactor at the desired power by compensating for drift in reactivity. This is different from safety rods, which are used for rapid shutdown, and from other absorbers that aren’t meant for fine compensation. So the rod that compensates changes in reactivity is the shim rod.

Shim rods provide fine, small adjustments to reactivity to offset the changes that occur during operation, such as fuel burn-up and temperature shifts. They are designed to be inserted or withdrawn a little at a time to keep the reactor at the desired power by compensating for drift in reactivity. This is different from safety rods, which are used for rapid shutdown, and from other absorbers that aren’t meant for fine compensation. So the rod that compensates changes in reactivity is the shim rod.