Calculations for the intermediate-spectrum cells of Zebra 8 using the MONK Monte-Carlo Code

The Monte-Carlo Code MONK 6A and its associated point-energy cross-section data have been used to analyse seven, zero-leakage, plate-geometry cells from the ZEBRA 8 assemblies. The convergence of the calculations was such that the uncertainties in k-infinity and the more important reaction-rate ratios were generally less than the experimental uncertainties. The MONK 6A predictions have been compared with experiment and with predictions from the MURAL collision-probability code. This uses FGL5 data which has been adjusted on the basis of ZEBRA 8 and other integral experiments. The poor predictions from the MONK calculations with errors of up to 10% in k-infinity, are attributed to deficiencies in the database for intermediate to fast spectrum systems. (author)