Calculational Methods for Interacting Arrays of Fissile Material describes the methods used in assessing the criticality safety of interacting arrays of fissile materials. It demonstrates that the behavior of neutrons in an array can be divided into two parts which can, to a large extent, be treated independently. These are the neutron multiplication within units of the array and the transmission of neutrons between units. For the former the usual methods of neutron physics are applicable but used so as to place emphasis on the neutrons entering and leaving the unit. The latter is mainly a geometrical problem, being entirely so for an air-spaced array. This volume is comprised of four chapters and begins with an introduction to the practical aspects of the interaction problem affecting arrays of fissile materials. The discussion then turns to simple "hand" methods of calculation, paying particular attention to the general equilibrium conditions in interacting arrays, along with the Oak Ridge method, the Interaction Parameter method, and the PQR method. Finally, the application of Monte Carlo method to the study of the neutron economy of entire arrays is considered in terms of one particular computer code called GEM. The basis of neutron tracking in critical size calculations by GEM is analyzed. This book will be a valuable resource for nuclear engineers and scientists.