A RANS Analysis of Pressurized Thermal Shock Phenomena in Nuclear Reactor Geometries Using Star CCM+
Abstract
Computational fluid dynamics (CFD) simulations were conducted using Star CCM+ in
order to investigate the mixing characteristics in the cold leg injection region of a
pressurized water reactor (PWR) pressure vessel. Through the use of CFD codes, this
present work seeks to characterize the mixing in this region in order to provide
information capable of impacting the reactor lifetime. The flow in the domain is driven
solely by buoyancy, through the use of two varying density fluids in an isothermal setup.
The fluids used in the experiment were a salt-water and ethanol-water mixture, for both
the heavy fluid and light fluid respectively. The simulated density difference was chosen
to be 10% and the cold tank fluid height was adjusted such that the static pressure across
the initial fluid-fluid interface would be zero. The simulation was conducted in the
Reynolds Averaged Navier-Stokes (RANS) framework, with focus on K-epsilon model.
Turbulent parameters and values for densities, velocities and Reynolds stresses were
gathered at locations of interest. These quantities of interest were gathered with the intent
on guiding the experimental analysis in preparation for a future verification and
validation study for the committee on the safety of nuclear installations. The simulated
results deviate from the available experimental data, this is due to a change in the material
properties and the solutions used in the experimental analysis. Despite this, the
simulations of the cold-leg mixing experiment behave physically as expected.
Citation
Mulloy Jr., John Patrick (2018). A RANS Analysis of Pressurized Thermal Shock Phenomena in Nuclear Reactor Geometries Using Star CCM+. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /174086.