DANKE: A Monte Carlo computer program for calculating the Dancoff correction factor for spheres, rods and slabs

In an array of fuel rods or fuel lumps, a flux of neutrons in the resonance energy region considerably decreases through absorption by the neighboring fuel rods or fuel lumps. The Dancoff correction factor is used to express this heterogeneity effect in obtaining the effective multigroup cross sections. Examination of MCDAN, a computer program for calculating the Dancoff correction factor using the Monte Carlo method, revealed two facts: (1) axial movement of neutrons were not considered arrays of fuel rods, (2) random distribution in radial argument of circle or sphere could not reproduce cosine distribution of neutrons at a surface point. Therefore, the program was revised for these points and further extended to be applicable to arrays of planes and hexagonal arrays of rods. The improved version was called DANKE program, which was incorporated into MAIL3.0, a computer code generating effective cross section sets for transport codes, in the nuclear criticality safety evaluation code system JACS. This report includes basic expressions that DANKE program adopts, a program manual and comparisons with calculations based on other methods. (author)