Computational design and numerical analyses of thermal-hydraulics in a PWR-type small modular nuclear reactor

This dissertation focuses on computational design of a PWR-type small modular nuclear reactor (SMR), and analysis of coolant thermal-hydraulics during steady-state operation. Physical design of the SMR is based on the existing AP-1000 and Small Modular Reactor designs by Westinghouse Nuclear. The first paper discusses a two-stage simulation of turbulent flow in the lower plenum of the RPV. In the first stage, four time-dependent Reynolds-Averaged Navier-Stokes (RANS) based turbulence models were used to simulate turbulent flow, compare predictions and identify an appropriate turbulence model. In the second stage, the selected turbulence model was once again used to simulate flow on a refined computational mesh (wall y+ \u3c 1) and compared with time-averaged predictions of the Large Eddy Simulation (LES) model. The LES model was also able to capture a cut-off for the spatial frequency of inertial flow scales in the lower plenum. The second paper uses simulation methodology established by Westinghouse Nuclear applied to resolving turbulent flow and heat transfer in a representative volume of the reactor core, as well as flow through the complex network of internal structures in the upper core. Predicted temperature profiles were in good agreement with design targets. The third paper describes a two-stage study; the first compares predictions of RANS based models in resolving turbulent flow past the integral pressurizer, identifies the most suitable turbulence model, which is used in the second stage to simulate turbulent flow and heat transfer through both, pressurizer and steam generator units --Abstract, page iv