CANDU
CANada Deuterium Uranium
CANDU reactor uses heavy water moderator and organic or light water coolant, enabling natural uranium fuel without enrichment.
Horizontal pressure tubes hold fuel bundles, with D2O moderator in calandria vessel separate from coolant. Units like CANDU-6 produce 700 MWe, with 19 operating mainly in Canada and South Korea. Refueling occurs online without shutdown.
Why it matters now
CANDU life extensions and refurbishments sustain Canadian output through 2026; heavy water design aids thorium cycles relevant to non-proliferation markets.