A Pump-sump system is used to supply water at thermal power or nuclear power plants for cooling. Recently, the size of pump-sump system has been reduced to cut down on construction costs. This leads to change in the design on intake location or the structure around the pump bell. In cases of improper design, undesirable vortices (free-surface and submerged vortices) or swirl occur at the vicinity of the pump column due to non-uniformity of the approach flow. This occurrence of vortex or swirl can create local pressure drop from which appears air-entrained water at the suction, leading to significant loss in the efficiency of the pumps or induce noise and vibrations. In order to restrain the submerged vortices, an Anti submerged-Vortex Device (AVD) is considered. In this study, Computational Fluid Dynamics (CFD) techniques are used to study the influence of various types of AVD on the submerged vortex and to validate the characteristics of the flow around the pump bell.