Evaluation of the boundary resonance effects in fast reactors by the first collision probability method

An efficient deterministic approach to the estimation of boundary resonance effects in fast breeder reactors is described, the approach is based on the method of probabilities of first collisions in subgroup representation and implemented in FFPR program. A number of fast breeder systems is investigated. The data are compared with the Monte Carlo method and point to a significant effect of fast boundary regions on criticality of ZPR-111-54 fuel assembly. The investigations of BN-1600 reactor model with heterogeneous core and annular feedstock insertions have revealed small boundary resonance effects and confirm the reliability of forecast of basic functionals derived in serial engineering design. The FF CPR program enables verification of traditional multigroup calculations for various classes of fast breeder reactors. 10 refs.; 6 figs.; 3 tabs