Development of a 3-D multigroup program for Dancoff factor calculation

Several parameters, one of which is the Dancoff Factor (DF), are used to calculate the resonance integral (RI) and reduced flux in the resonance region of heterogeneous systems as well as to accurately determine the group constants for criticality calculations. This paper is a report on the development of a program to calculate the DF correction factor using Monte Carlo method and collision probability definition in three-dimensional (3-D) geometries and with multi energy groups. Hence, the DF for any arbitrary arrangement of cylindrical and slab fuel elements is hereby calculated. The fuel elements are monitored and kept at equal levels, though different material compositions and formations are allowed rendering the materials either black or partially transparent. A separate investigation is carried out as to the effects of extension to 3-D geometry, energy group divisions, clad, coolant and moderator. The program is applied to calculate DF for slab fuels of a pool-type research reactor (PRR) containing 19 slab fuels and for cylindrical fuel element of CANFLEX fuel bundle with 43 cylindrical fuels elements. All calculations are performed in 3-D geometry and for six energy groups. The viability as well as the feasibility of the program is verified using the WIMSD computer code for the obtained 3-D and six-group DF for CANFLEX fuel bundle.