Experimental Investigation on Thermal-Hydraulic Interaction between CMT and SIT of a Single-Train Passive Safety System during an SBLOCA Test

An integral type reactor, SMART has been equipped with an additional passive safety system (PSS), which maintains the reactor in a safe condition during the design basis accident without any AC power to drive the safety injection pumps and operator action with no more than 72 hours. For verification of this SMART passive safety system, a single train of a passive safety system consisting of a core makeup tank (CMT), a safety injection tank (SIT) and two stages of an automatic depressurization system (ADS) were attached additionally to the existing SMART-ITL facility. Two CMTs with different lengths while having the same volume were installed. CMT No.1-1 and CMT No.1-2 have the same volume. The vertical length of the CMT No.1-2 is one-half of the CMT No.1-1. They have different header diameters. To evaluate the effects of the header diameter of CMT, this test (S109) using CMT No.1-2 was carried out under the same procedure and conditions as the test (S108) using CMT No.1-1. This report describes the test procedure and test result of an SBLOCA simulation to evaluate the performance of a passive safety system consisting of CMT No.1-2, SIT No.1, ADS No.1 and ADS No.2. The C-type Flow distributors were installed in the upper part of CMT and SIT. The initial condition of the test is the same as the steady-state operating conditions. The test was carried out according to the sequence of events (SOE) for an SBLOCA scenario. Most of the thermal-hydraulic properties such as the pressure, temperature, flow rate, and water level showed partially transient phenomenon with the operation of the passive safety system, but the injection characteristics of the CMT and SIT showed good and stable behavior from a macro perspective. In this paper, only the results of S109, which were similar to the results of S108 qualitatively and quantitatively, are presented. An SBLOCA test on the SI line break was conducted to evaluate the injection performance between the CMT and SIT of an integral small reactor. The steady state required by the procedure as the initial condition was well maintained