CANDU reactors(pressurized heavy water reactor)

It uses un enriched Uranium as its fuel while Heavy water serves as coolant and neutron moderator. The heavy water is kept under high pressure,allowing it to be heated to higher temperatures without boiling,like in pressurised water reactor

Pros:

  • Requires very little uranium enrichment.
  • Can be refueled while operating, keeping capacity factors high (as long as the fuel handling machines don’t break).
  • Are very flexible, and can use any type of fuel.

Cons

  • Some variants have positive coolant temperature coefficients, leading to safety concerns.
  • Neutron absorption in deuterium leads to tritium production, which is radioactive and often leaks in small quantities.
  • Can theoretically be modified to produce weapons-grade plutonium slightly faster than conventional reactors could be.