Albedo-Monte Carlo technique for neutron streaming through ducts

The usefulness of the Albedo-Monte Carlo method for problems of neutron streaming through ducts in shields is studied. An experiment on thermal neutron streaming through a duct in concrete was simulated and the results are reported. The details to which albedo data is required for this problem, is investigated. Assuming the albedo to be constant over the reflected polar and reflected azimuth angles, overestimates the streaming flux at points deep in the duct by a factor of 4.5. Assuming the albedo to be constant over the reflected azimuth alone underestimates the streaming flux by a factor of 1.8. Using a detailed albedo as a function of incident polar, reflected polar and reflected azimuth, we are able to predict the streaming flux within 18%. The feasibility of this procedure for neutron streaming through twolegged duct is shown. (orig.)