Coupled burnup calculations with the serpent 2 Monte Carlo code

This article describes the implementation of a burnup scheme with coupled fuel behavior feedback into the Monte Carlo code Serpent 2. The new capabilities are applied to estimate the effects of typical simplifications concerning the fuel temperature distribution in the burnup history part of group constant generation. A set of group constants are generated for an assembly of the EPR by executing the burnup history calculation with either an assembly wide constant effective fuel temperature or realistic pin-wise fuel temperature distributions provided by a coupling to an external fuel performance solver. The differences in nuclide concentrations and generated group constants are quantified and the benefits of using a separate effective temperature for burnable absorber rods is investigated