[en] This paper describes the thermalhydraulic characteristics of CANDU-6 reactors' fuel channel loaded with CANFLEX-RU (CANDU Flexible Fuelling - Recycled Uranium) bundles. The NUCIRC code, recently updated with the pressure drop and critical heat flux(CHF) models of CANFLEX bundle, is used to evaluate the thermalhydraulic characteristics of the CANFLEX-RU fuel channel such as the distributions of channel flow rate, channel exit quality, Critical Channel Power(CCP) and Critical Power Ratio(CPR). This paper also examines the effects of pressure tube creep and bearing pads height on the thermalhydraulic characteristics. The distributions of channel flow rate and CCP for CANFLEX-RU fuel channel show the typical thermalhydraulic characteristics of CANDU-6 reactor channel, and the CPR keeps greater than 1. 455. Considering the pressure tube creep for CANFLEX-RU bundle, the decrease of the CCP for CANFLEX-RU fuel channel is less than that for 37-element natural uranium fuel channel. Raising bearing pads height from 1.4 mm to 1.8 mm, the CCP enhancement is estimated to be about 2%