Question

Canadian nuclear reactors are run with naturally occurring uranium and must therefore use D₂O as a moderator/coolant. Explain why normal water can’t be used as a moderator/coolant in Canadian reactors.

Answer 1

For the efficient operation of a nuclear reactor, it is necessary to slow down the neutrons, the process is known as moderation.

Heavy water (D₂O) is used as a moderator in nuclear reactors. Heavy water can slow down neutrons more than normal water. Ordinary water is also used in nuclear reactors, called light water reactors, but normal water captures more neutrons and thus the chain reaction cannot continue for long. So that Canadian nuclear reactors use heavy water as a moderator for effective fission.