The Advanced CANDU ® 1CANDU ® (CANada Deuterium Uranium) is a registered trademark of Atomic Energy of Canada Limited (AECL). 1 Reactor ACR ® 2ACR ® (Advanced CANDU Reactor) is a registered trademark of Atomic Energy of Canada Limited (AECL). 2 is a new type of CANDU reactor that is slightly-enriched-uranium fuelled, light-water cooled, and heavy-water moderated. The characteristics of the ACR lattice therefore differ somewhat from those of the standard (natural-uranium fuelled and heavy-water cooled) CANDU lattice. Consequently, the validity of the older neutronic-analysis methodology employed for the natural-uranium CANDU lattice and, in particular, that of the standard homogenization method used for that type of lattice, need to be investigated for the ACR lattice. Of particular interest are configurations in which neutronic properties of lattice cells alternate in a checkerboard pattern. Such patterns occur in CANDU reactors because of alternating fuelling directions in neighbouring channels and because neighbouring channels belong to different coolant loops or different passes within the same loop. The work presented in this paper assesses the accuracy of the standard homogenization method when applied to checkerboard ACR-lattice configurations and investigates whether the use of Generalized Equivalence Theory (GET) yields more accurate results. The conclusion is that the most accurate results, aside from using exact (or, at least, leakage-corrected) macroscopic cross sections and discontinuity factors, can be obtained by using exact (or, at least, leakage-corrected) macroscopic cross sections and no discontinuity factors. The expected errors in the latter case, assuming a 6-cm or finer Cartesian mesh, are less than 1% in bundle power and less than 1mk in k eff .