Experimental and analytical investigation on SMART passive safety systems for three 2-inch SBLOCA tests using SMART-ITL

•Three 2-inch SBLOCA tests were conducted with an integral effect test facility, SMART-ITL, and were simulated using a system analysis code, MARS-KS.•The RV water level was comparably affected by more PSIS trains and less PRHRS HX tubes combined with smaller orifices.•The suspension of CMT injection could be simulated by imposing the heat loss at the CMT wall, which caused more steam flow through PBL, or more pressure drop. The SMART-ITL facility is an integral test loop for SMART, a 360 MWt integral type reactor. Using this facility, several design-basis and performance tests were conducted to validate the passive safety systems of SMART. Among these, three 2-inch small-break loss-of-coolant accident tests were introduced, where the operating conditions of the passive safety injection system (PSIS) and passive residual heat removal system (PRHRS) were different. The main difference between the test results was in the reactor vessel (RV) level. Both PSIS and PRHRS contributed to the RV levels. The tests were also simulated using a system analysis code, MARS-KS. Using the code, major parameters were predicted reasonably well. The physical phenomena behind core makeup tank (CMT) injection were explored in depth by referring to the code calculation results, and the suspension of CMT injection was simulated by considering the heat loss at the CMT wall.