Due to the growing international concerns about the need to convert research reactors cores to the use of low enriched uranium fuel, Tajoura reactor core was converted from the use of the high enriched uranium fuel (HEU) to the use of low enriched uranium fuel (LEU). For this purpose, a conversion program had been put down (in 2006) which includes the recalculation of all safety related aspects, namely the neutronic and thermal hydraulic calculations. In this work the results of the hydraulic testing of the new core is provided . These parameters include the new flow rates for the new core, pressure drop, and negative pressure under the core. This task is performed experimentally. The procedure of these experiments is provided. The results of these experiments show that flow rate through the reactor core is less than that of the high enriched core, therefore it is essential to recalculate thermal hydraulic parameters of the reactor core to specify the normal values of the most important technological parameters and their operational limits. The comparison of these parameters between using the HEU and LEU fuel is provided.