CRITICALITY ANALYSIS OF URANIUM STORAGE FACILITY WITH FORMATION RACKS.Uranium materials are needed for the uranium fuel production of research reactors and radioisotope. Before the uranium material is used, it is stored in the storage facility. One of the prerequisites for uranium material storage facilities is that it must be in the sub-critical condition. The purpose of this study is to analyze the criticality condition of uranium material storage facility located in PT. Inuki (Persero) and to ensure that the criticality condition is always in sub-critical state. Criticality analysis was performed using MCNP-5 program to determine the level of criticality of the three uranium material storage facilities at initial conditions and conditions after adding the storage racks. For analysing storage facilities 1 and 2, three scenarios of container on the storage rack formations were considered. Meanwhile, for analysing the storage facility 3, one scenario was considered. The results confirm that all strorages at initial condition and after adding storage racks formation were still in sub-critical condition (k-eff<1). These results are then used as the basis for the uranium materials management. It is also used as a basis for issuing an operational license by the nuclear energy regulatory body (BAPETEN).