Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is
Correct answer: D. to slow down the neutrons to thermal energies
- A. to control the energy released in the reactor
- B. to absorb neutrons and stop the chain reaction
- C. to cool the reactor
- D. to slow down the neutrons to thermal energies
Explanation
D is the right option because : The function of a moderator in a nuclear reactor is to slow down the fast neutrons produced by nuclear fission reactions to thermal energies. Thermal neutrons are more likely to induce further fission reactions in fissile materials like uranium-235. Heavy water (deuterium oxide, D2O) is an effective moderator because it contains deuterium, which has a higher mass and therefore slows down neutrons more effectively than ordinary water.
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