Fission matrix based Monte Carlo criticality calculations

We have described a fission matrix based method that allows to cancel the inactive cycles in Monte Carlo criticality calculations. The fission matrix must be sampled in the course of the Monte Carlo calculation using a space mesh with sufficiently small zones as it causes the fission matrix be insensitive to errors in the initial fission source. The keffkeff and other quantities can be derived by means of the final fission matrix. The confidence interval for the keffkeff estimate can be conservatively determined via the variance in the fission matrix.