A CFD Analysis of Complex Flow Distribution in KSNP Reactor Vessel Lower Structures Based on 3D CAD

During design period and commercial operation of a nuclear power plants (NPP) lots of safety analyses are performed because nuclear regulatory body requires the vendor and utility to report lots of simulation results in order to ensure the safe operation of the NPP. In general, the simulations are carried out using vendor-specific design codes and best-estimate system analysis codes. The thermal-hydraulic system codes have powerful features such as multi-phase flow model, phase-change model and event programming. During the past decade, however, computing power has been dramatically enhanced in terms of speed, capability and expenses. On the other hand, mechanistic computational fluid dynamics(CFD) codes also made a progress during these days. Nowadays, commercial CFD programs are applied to very large and complex systems design such as core design, HVAC design and chemical plant buildings. In spite of the recent progress in computing hardware and software the nuclear industry still uses conventional system codes based on lumped parameter model. It is believed to be beneficial to take advantage of advanced commercial CFD codes in safety analysis and design of NPPs