Performance of the Explicit Euler and Predictor-Corrector–Based Coupling Schemes in Monte Carlo Burnup Calculations of Fast Reactors

We present a stability test of the explicit Euler and predictor-corrector–based coupling schemes in Monte Carlo burnup calculations of the gas fast reactor fuel assembly. Previous studies have identified numerical instabilities of these coupling schemes in Monte Carlo burnup calculations of thermal spectrum reactors due to spatial feedback–induced neutron flux and nuclide density oscillations, where only sufficiently small time steps could guarantee acceptable precision. New results suggest that these instabilities are insignificant in fast-spectrum assembly burnup calculations, and the considered coupling schemes can therefore perform well in fast-spectrum reactor burnup calculations even with relatively large time steps.