Thermally induced cracking of the UO2 fuel pellets undoubtedly results in some reduction of the effective fuel thermal conductivity, relative to that for solid UO2. This effect may be approximated by appropriately chosen “crack factors” that reduce the solid-UO2 thermal conductivity. We demonstrate that the assumption of reduced fuel conductivity always results in a reduction of the fuel stored energy that is inferred from fuel centerline temperature data. This reduction occurs whether the crack factors are introduced as simple constants or as functions of radial position within the fuel pellet. If fuel performance computer codes remain “tuned” to the current body of centerline temperature data, those codes will predict lower fuel stored energy when fuel cracking is taken into account regardless of the modeling assumptions invoked. Accounting for fuel cracking should lead to a reduction in calculated peak cladding temperatures obtained in some loss-of-coolant accident simulations.