Validation studies performed with mixed Pu + U aqueous critical experiments in annual geometry

This paper discusses the results of a calculational study that was performed to validate the SCALE computer code system using data from critical experiments performed with mixed Pu + U agueous solutions. The critical experiments were conducted in an annular vessel where the fissile solution was placed in the annulus, and various inserts and bottles containing fissile solution were located in the inner portion of the vessel. These experimental activities are part of a joint exchange program between the US Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan in the area of criticality data development. The experiments were conducted at the Battelle Pacific Northwest Laboratory's Critical Mass Laboratory (CML). In summary, calculated multiplication factors have been examined for 18 critical experiments conducted in annular geometry with mixed Pu + U solutions. The results indicate that the SCALE computer code system with CSRL cross sections is capable of accurately modeling mixed fissile systems in annular geometry