A rigorous computational procedure is presented for dynamic response analysis of horizontal tube array in partially-filled calandria including hydrodynamic interaction effects. The procedure is general enough to consider transfer of energy between the fluid-coupled tubes, effects of moderator sloshing in terms of magnitude and the distribution of hydrodynamic forces on tubes, and wave absorption by the fluid boundaries. The analysis method is based on the substructure approach in which individual tubes, calandria shell, inside moderator domain and the outside vault water domain are treated as different substructures. Numerical evaluation procedures for various substructures and sample response results for typical tubes have been presented to demonstrate the capabilities of the developed procedure.