[en] To get complete information about condition of failure of secondary cooling system, the simulation of loss of secondary coolant flow of Bandung TRIGA 2000 reactor under the operation of 2000 kW power has been done, by applying computer program RELAP5/MOD3.2. At this research, core of Bandung TRIGA 2000 reactor is modeled in the form of seven channels core. On this simulation was assumed that secondary pump actuator got loss of power, so failed in function. The result of calculation in condition of steady state indicated that the initial condition of steady state was reached 2500 seconds after reactor started operation on 2000 kW power, the hottest channel cladding temperature was 150,63°C, the hottest channel coolant outlet temperature was 111,36°C, reactor inlet temperature was 35,52°C, and reactor outlet temperature was 45,75°C. The result of calculation in transient condition showed that before scram occurred, the hottest channel cladding temperature was 159,78°C and the hottest channel coolant outlet temperature was 115,86°C. After scram occurred, that was 150 seconds after failure of secondary pump, reactor inlet and reactor outlet temperature were always increasing to 53,15°C due to the heat of fission product.(author)