On the observation of discrepancies in the 16O(n,α) data between different evaluated nuclear data files

The disagreement of calculational results on the fast neutron flux at the pressure vessel of a pressurized water reactor obtained with modern neutron data libraries based on Endf/B-VI.8, JEF-2.2 and JENDL-3.3 evaluations and using MCNPX Monte Carlo neutron transport code is analysed. Comparison of the neutron cross sections data important for the considered study and taken from these libraries has indicated that the observed results disagreement could be explained by differences in the 16O(n,α) data and this is examined and discussed in the paper. The major conclusion of the given study is that presently the uncertainties in the 16O(n,α) data could be considered as an important contribution to the overall fast neutron fluence calculational uncertainty. (authors)