[en] Accurate and complete nuclear data are a fundamental requirement for any nuclear reactor model. One major challenge to the modeling of advanced nuclear reactor systems is the lack of sufficient nuclear data for the operating conditions and materials relevant to the advanced systems. The Canadian Supercritical Water-Cooled Reactor (SCWR) is an advanced reactor concept which, like all advanced GEN-IV reactor concepts, differs significantly in operating conditions, fuel composition and non-fuel materials from conventional reactors. The Canadian SCWR is a pressure tube-based reactor with heavy water moderator and light water coolant, intended to operate with a coolant pressure of 25 MPa and temperatures ranging from 350 ^oC (inlet) to 625^oC (outlet), with (Pu,Th)O₂ fuel, using advanced fuel bundle and fuel channel designs. Because of these differences from conventional heavy water (HWR) and light water (LWR) reactors, it is not clear whether presently-used core modeling methods or nuclear data libraries are adequate for SCWR modeling. In this paper, an idealized model of an SCWR fuel channel with fresh fuel is modeled in order to examine the nuclear data contributions to the sensitivity and uncertainties in the neutron multiplication factor, k, and various lattice reactivity coefficients. (author)