Computational studies on pressurized thermal shock in reactor pressure vessel

Abstract

Pressurized Thermal Shock (PTS) in the Reactor Pressure Vessel (RPV) can occurs during injection of Emergency Core Cooling (ECC) water into the cold leg of Pressurized Water Reactor. Injected ECC water generates large temperature gradient which leads to large thermal stresses in the RPV wall. To study this behaviour in Rossendorf Coolant Mixing Model (ROCOM), case of buoyancy driven mixing with a constant flow rate and 10% density difference between the ECC injection and loop water was taken for analysis. ROCOM is a 1:5 scaled German KONVOI type reactor having four-loop with a RPV mock-up made of transparent acrylic material. Large Eddy Simulation (LES) and Reynolds Averaged Navier–Stokes equations (RANS) based models are used for this numerical analysis work in OpenFOAM CFD code. LES offered more accurate predictions of the local and spatial mixing phenomena compared to RANS based models. The predicted results are compared and validated with experimental data of ROCOM test facility. It shows that results are in good agreement.