MOCAL, a Monte Carlo albedo code

The MOCAL code is a Monte Carlo code that uses pre-existing albedo data files to determine neutron penetrations into shielding air gaps. By using the albedos along the bounding surfaces of the gaps, expensive computational tracking of neutrons through material regions is eliminated. Thus, the run-time for MOCAL is relatively short, compared to conventional Monte Carlo methods of tracking neutrons completely through the materials. Also as a result of this albedo treatment, MOCAL is very easy to use, with the time required to prepare a typical input data file to be less than 15 minutes in most cases.