<p>Decay heat is usually discharged by a new natural circulation method in fast reactor, which was an important passive safety measure to prevent power station blackout. The natural cycle and forced cycle will produce different thermal and hydraulic characteristics. In addition, the natural circulation produces different hydrothermal phenomena on the secondary side by means of Direct Reactor Air Cooling System (DRACS) and primary reactor auxiliary cooling system (PRACS). The Plant Dynamics Test Loop (PLANDTL-DHX) test device were built to validate the DRACS and PRACS performances, including the natural convection flow behavior and decay heat removal in the core. In the present work, a "separated modular modeling and integrated calculation method" was developed to conduct three-dimensional numerical modeling and calculation for the PLANDTL-DHX platform. Meanwhile, the steady-state verification of PLANDTL-DHX was carried out and compared with the design parameters. On this basis, the transient operating conditions of DRACS were calculated, and the temperature, flow distribution, and transient variations of the key positions such as center subassembly, upper plenum, and IHX were preliminarily obtained. Based on the test results, the numerical calculation is verified. The calculated results prove that the "separated modular modeling integrated calculation" method was applicable to simulate the three-dimensional transient thermal and flow characteristics of DRACS natural circulation decay heat removal in PLANDTL-DHX, which provide important numerical references for the following operation and design of the high power fast reactor.</p>

Three-Dimensional Numerical Simulation on Transient Natural Circulation DeviceCharacteristics of DRACS in PLANDTL-DHX Experimental Device

Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE28/volume/85246

2021 28th International Conference on Nuclear Engineering (ICONE28)

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