Estimation of the Effect of Small Perturbations in Multivariant Calculations Using the Prizma-D Computer Program

In eigenvalue problems, in contrast to problems with a fixed source, the perturbation introduced into the system affects the distribution of the fission points of the source. The method of “small iterations on fissions” was developed to take account of this influence. This method is used together with a special method for simulating trajectories. The crux of the method is that for all variants of the problem the initial source is a source for the unperturbed variant, after which, to establish the source for each variant, iterations on fissions are performed in the second part of the computational cycle using a special method of simulation. The possibilities of using the method of “small iterations on fissions” are demonstrated with calculations performed for several problems and the comparative results are presented. __________ Translated from Atomnaya Energiya, Vol. 99, No. 3, pp. 203–210, September, 2005.