Design and Analysis of Integrated Test Facility Based on Small Break Loss of Coolant Accident for AHPR1000

Abstract Nuclear energy has the potential to provide a large amount of green and clean energy throughout the world. However, in the process of nuclear energy development, safety has always aroused a lot of attention, especially after the Fukushima incident, safety has become an important condition restricting the development of nuclear power. In the design process of the third-generation nuclear power plant, the incorporation of passive and active safety concepts has further enhanced the defense-in-depth capabilities and demonstrate the effective safety function in both design base accident and design extension condition. To verify the effectiveness of safety system independently designed for next generation of HPR1000, this paper selected important thermo-hydraulic phenomena from phenomenon identification and ranking table in small break LOCA, designed and built an advanced integrated test facility with height ratio of 1:3, volume ratio of 1:90 and power ratio of 1:52 through proportional analysis method of H2TS. It has the test ability to simulate the natural circulation stage, the pressure relief blowout stage, the injection stage of the refueling water storage tank, and the long-term sump recirculation stage. The test facility adopts full pressure design, with consideration for medium-pressure operation capacity, has fully covered the main loop, safety system, auxiliary system and other important systems of the reactor plant prototype. At the same time, it has the function of coupling operation with the containment vessel test device, which can release the mass energy to the vessel and accept the steam reflux condensation. In terms of isothermal, isobaric and equal physical properties simulation, the test parameters have reached the international advanced level, and can carry out multi-condition tests in design basis conditions and design extension conditions, as well as multi-plant tests in active and passive plant. In addition, the test facility has the ability to provide test data under accident conditions, verify safety analysis procedures, and study the impact of key equipment and main operating parameters on the defense-in-depth function under passive and active systems. The test facility could operate stably under high pressure medium pressure and low pressure. Also, the system is sensitive to small break accidents. The distortion evaluation shows that the parameters of the test facility face a good match with the prototype, which can be used to study the key phenomena and safety characteristics of the safety system and confirm the effectiveness of the safety design of AHPR1000.