The Ben Gurion University 15-MeV“clean” neutron field is used to investigate various problems encountered in fusion reactor blanket designs. In particular, the adequacy of the 7Li tritium production neutron cross section was analyzed by comparing measured neutron energy spectra in a lithium tank with detailed Monte Carlo calculations. It is seen that new evaluations are needed that would consider the various mechanisms that contribute to tritium production in 7Li and determine the shape of the secondary neutron energy spectrum. It is also found that uncertainties in the alignment of the source-target-detector configuration in integral experiments may result in considerable discrepancies in the analyses of such experiments.