Monte Carlo burnup code development based on multi-group cross section method

A multi-group cross section method was developed based on MOBAT code to save computing time. First, three PWR pin cell benchmark cases were computed by MOBAT, MCODE and SCALE. The results of the separate benchmark cases are consistent with each other; the maximum deviation of reactivity at a burnup depth of 100 MWd/kgU is less than 600 pcm, and the difference in nuclide concentrations is within 5%. Next, the same benchmark case was calculated by MOBAT using the multi-group cross section method. The results indicate that the method can give credible results while greatly reducing the computing time. Comparing the original MOBAT benchmark case to the results of the multi-group cross section method, the reactivity difference at a burnup depth of 100 MWd/kgU is about 100, the difference of nuclide concentrations is within 1%, and computation time was 3.5 times faster.