State the reason, why heavy water is generally used as a moderator in a nuclear reactor.

State the reason, why heavy water is generally used as a moderator in a nuclear reactor.
State the reason, why heavy water is generally used as a moderator in a nuclear reactor.
State the reason, why heavy water is generally used as a moderator in a nuclear reactor.
State the reason, why heavy water is generally used as a moderator in a nuclear reactor.

reactor.