The Physics and Fuel R&D program provides AECL’s technology base in reactor and radiation physics and fuel, for both operating CANDU and research reactors, as well as new reactor development.

AECL’s physics codes and fuel performance/design codes provide a fundamental understanding of fuel performance to support existing fuel designs and advanced fuel technology. Currently, operating CANDU power reactors use a once-through natural uranium fuel cycle, which avoids the need for securing a supply of enriched uranium. Through our fuel cycle program, we are investigating a number of other fuel cycles, including Slightly Enriched Uranium (SEU), Recovered Uranium (RU), Direct Use of spent Pressurized water reactor fuel In CANDU (DUPIC), Mixed oxide (MOX) and Thorium. RU, a promising variant of SEU, is obtained from conventional reprocessing of used light water reactor (LWR) fuel. The use of SEU fuel in CANDU can reduce fuelling costs, increase the amount of power produced, and reduce back-end wastes.

The natural synergy between CANDUs and LWRs is being developed by advancing the DUPIC fuel cycle. Here LWR fuel is recycled into CANDU reactors using a simple (relative to chemical-based reprocessing technology), proliferation-resistant method. At the same time, AECL's research into thorium fuel cycles will ensure that CANDU reactors have a viable fuel supply for the foreseeable future. Thorium, as a "breeder" material in CANDU reactors would avoid the necessity of developing expensive fast breeder reactors.

In addition to fuel cycle activities, AECL is developing new fuel bundle designs that are improved fuel carriers for both current and future CANDU reactors. The basis for these designs is the new CANFLEX Mk IV bundle, which allows a combination of higher fuel burn up, higher channel powers and increased operating margins. CANFLEX has been successfully demonstrated in the Point Lepreau CANDU reactor in New Brunswick, Canada.