The present paper deals with the analysis of the performances of a very large Annular Linear Induction Pumps (ALIP) for liquid sodium. This pump is able to provide high flow rates (more than 7,000 m3.h-1 with a pressure discharge of about 3.7 bar). Dimensions of pumping channel under the active part are of an average diameter of 966 mm and a length of 4,500 mm. It’s a double sided inductor pump. On the base of an imposed 2D axisymmetric geometry, performances (discharge pressure vs. deliver flowrate) are calculated by means of two methods for the point of optimal frequency of the supply currents. In a first approach, Maxwell equations are solved taking into account a rigid body velocity field for the fluid. These calculations give the opportunity to determine the most suitable operating frequency of the supply currents and their average intensity. In a second approach the full magnetohydrodynamic interaction is computed (using k-e turbulent law with enhanced wall functions). A comparison is done between the results obtain from the two hypotheses: rigid body velocity field vs. computed turbulent flow field. This set out that rigid body velocity field lowered the pressure discharge.