Application of MONK and MCBEND to Transport Flask Design Assessment

Abstract

Safe operation of nuclear fuel transport flasks is of fundamental importance and is ensured by compliance with IAEA and national regulations. Criticality and shielding analyses of flask designs in both normal and accident conditions are required to demonstrate compliance. In recent years increased computing power has facilitated the use of the Monte Carlo method for such analyses as standard. The method is an improvement over earlier methods because approximations in geometry, scattering angle/energy and reaction cross sections can be significantly reduced and in some cases effectively eliminated. In this paper the application of the Monte Carlo codes MONK and MCBEND, developed by AEA Technology and BNFL, to such analyses is described, with emphasis on features which facilitate accuracy and ease of use.