An Empirical Model for Safe Pipe Intersections Containing Fissile Solution

An empirical model is presented for calculating safe nuclear criticality parameters for systems of intersecting pipes containing enriched uranyl nitrate solution. The model, which applies to systems consisting of a main pipe (the central column) from which smaller pipes (arms) branch off, uses as a criticality parameter the area of intersection of the arms with the column. Maximum safe values for both the central column diameter and the area of intersection of the arms with the column are provided for conditions of minimal, nominal, or full reflection. The current model, an extension of an earlier one, is based on Monte Carlo calculations as well as on experimental data. A review of the experimental and calculational data is included.