CANDUderived

CANDUderived refers to reactor designs and related technology that are derived from the CANDU family, the Canadian heavy-water moderated, natural uranium fueled reactor concept developed by AECL. Core features of CANDU-derived designs include a heavy-water moderator and primary coolant, pressurized natural uranium fuel in horizontal pressure tubes, and the capability for online refueling. The calandria, containing the moderator, remains separate from the primary heat transport system, allowing the fuel to be replaced without shutting down the reactor. This combination provides good neutron economy and fuel-cycle flexibility.

Most CANDU-derived reactors use heavy water as both moderator and coolant; however, some later derivatives—such as the Advanced CANDU Reactor (ACR)—employ light-water coolant and slightly enriched uranium, while attempting to retain the CANDU design philosophy and safety features.

Origins and spread: the original CANDU program in Canada inspired a family of reactors built and operated in several countries. Design variants such as CANDU 6 and other export versions have been built or adapted beyond Canada. India, in particular, developed a large fleet of PHWRs based on CANDU-derived technology, and other nations have pursued similar reactor concepts under license or collaboration.

In current energy and nonproliferation discourse, CANDUderived serves as a classification for reactors drawing on the CANDU approach rather than a single model. The term emphasizes lineage, fuel flexibility, and the use of heavy-water moderation, while acknowledging ongoing evolution in materials, fuel, and safety design.