Estimating the effects of homogenized fuel temperature in group constant generation using Serpent 2

The main findings state that while the use of an effective temperature model leads to significant differences in the radial nuclide distributions, the assembly wide homogenized group constants are reproduced fairly well and the effects on the simulation of the EPR initial cycle are modest, although interesting axial and radial power redistribution can be observed due to the slower speed of gadolinium burnout when effective fuel temperatures were used. The results indicate that better results for the full core calculations could be obtained by using a separate effective temperature for the burnable absorber rods in the burnup calculation and by considering the fuel temperature history effect in the group constant parametrization.