The CANDU reactor has the most potential for fuel cycle flexibility of any reactor type because of its simple fuel design, on-power refuelling capability and excellent neutron-efficiency. These features allow CANDU reactors to use natural uranium fuel, low enriched uranium (LEU) fuel, recovered uranium, thorium and the direct use of spent Pressurized Light Water Reactor (PWR) and Boiling Water Reactor (BWR) fuel. AECL is continuing to develop fuel options for the current and future CANDU reactors.

CANFLEX Advanced Fuel
Our advanced CANFLEX (CANDU FLEXible) fuel bundle was developed specifically for advanced fuel cycles. Its benefits include enhanced reactor performance and safety margins. AECL has successfully designed, qualified and implemented the CANFLEX 43-element bundle design. The successful proof-testing of the CANFLEX design in CANDU commercial reactors is the result of close cooperation with domestic and international organizations. CANFLEX-ACR fuel is the reference for AECL’s Advanced CANDU Reactor, the ACR-1000.

Low Void Reactivity Fuel (LVRF)
AECL has completed the qualification of the CANFLEX LVRF bundle design. This involved extensive state-of-the-art qualification analysis and out-reactor testing covering design analysis, reactor physics, thermalhydraulics, mechanical behaviour and dysprosium behaviour. The CANFLEX LVRF contains slightly enriched uranium and dysprosium, and increases the safety margins during various postulated accident scenarios. It provides the ability to uprate by allowing a significant increase in reactor operating power. The CANFLEX LVRF bundle will also provide improved critical channel power, resulting in higher thermalhydraulic margins to offset the effects of reactor aging. The bundles will be installed in two fuel channels in the Bruce NGS B reactors (located in Ontario, Canada) as part of the planned Demonstration Irradiation Program.