Fast Computation of the Neutron Flux Distribution in X-Y Geometry Using the QP0 First Collision Probability Method

摘要

For the space dependent condensation of cross section libraries with a large number of free energy groups a fast method is developed to calculate the neutron spectrum in rectangular multicells. Material zones in any given arrangement are divided into uniform meshes using an overall mesh grid. Inside each mesh the neutron flux is assumed to be spatially constant. The boundary currents are approximated using quadrupole cosine distribution. In contrast to the 'surface currents' method the authors use QP0 collision probabilities which are represented as product sums of a set of first collision probabilities for single meshes. The theoretical and programming work had been finished already in 1976 and the results described in an internal EIR report. (Atomindex citation 13:648197)