A shortcoming of NITAWL/BONAMI causing problems in KENO calculations

A serious error may occur in Monte Carlo calculations with the code KENO-Va if self-shielding of the fissile isotopes is important and if the quantity ν·σf is given under MT=1452 on the AMPX-W data file. It appears that this product has not been corrected for the self-shielding, which should have been done in the BONAMI and the NITAWL modules. Other complications may arise if first- and higher-chance fission cross-sections are given separately on the AMPX-M data file. The subroutine CRRCT of the NITAWL module and the subroutines FUDGE and FODGE of the BONAMI module have been improved to overcome these problems. (author). 5 refs.; 1 fig.; 3 tabs