Measurements of Angular Flux on Surface of Li₂O Slab Assemblies and their Analysis by a Direct Integration Transport Code “Bermuda”

Angle-dependent neutron leakage spectra above 0.5 MeV from Li₂O slab assemblies were measured accurately by the time-of-flight method. The measured angles were 0°, 12.2°, 24.9°, 41.8° and 66.8°. The sizes of Li₂O assemblies were 31.4 em in equivalent radius and 5.06, 20.24 and 40.48 em in thickness. The data were analyzed by a new transport code “BERMUDA-2DN”. Time-independent transport equation is solved for two-dimensional, cylindrical, multi-regional geometry using the direct integration method in a multi-group model. The group transfer kernels are accurately obtained from the double-differential cross section data without using Legendre expansion. The results were compared absolutely. While there exist discrepancies partially, the calculational spectra agree well with the experimental ones as a whole. The BERMUDA code was demonstrated to be useful for the analyses of the fusion neutronics and shielding.