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Railways PYQCBT 1 2016

RRB NTPC · Question 16

What does the control rod (cadmium rod) do in a nuclear reactor? A. The fission absorbs excessive heat generated during the reaction and thus prevents excess temperature rise. B. Absorbs extra neutrons to control the chain reaction. C. Reduces the energy of neutrons so that they can be further used for the fission reaction. D. The chain produces the neutrons required for the fission reaction.

  1. D

  2. B

  3. C

  4. A

Show answer & explanation

Answer: (B) B

Explanation

Control rods of cadmium or boron absorb excess neutrons, keeping the chain reaction steady. Moderators such as heavy water or graphite slow neutrons down.