A perturbation method for pointwise nuclide depletion calculations

perturbation method has been developed for computing local nuclide densities to reduce the expense of performing a large number of isotopically detailed depletion calculations. In this method, deviations of local reaction probabilities from node-average values are used to estimate the associated deviations in depleted nuclide densities. The accuracy of the method has been tested by performing several fast reactor numerical calculations. The results indicate that the perturbation method is very accurate for fast reactor applications, while being sig- nificantly more ecient. The first and second order perturbation methods are more ecient than the explicit solution of local burnup equations by factors of ~100 and ~5, respectively