Observations and Measurements of Two-Phase Flow Phenomena in a Water-Cooled Reactor Cavity Cooling System During Transient Scenarios
Abstract
The WRCCS is a cooling system in which the sole function is to remove heat from a VHTR, MSR reactor, or any reactor operating at high temperature. WRCCS was chosen for the experiment as opposed to an air-cooled reactor cavity cooling system. The research purpose was to observe two-phase flow and conduct measurements of temperature and flowrate during transient scenarios in the RCCS during two-phase flow. The WRCCS can operate in both single-phase during normal operations and two-phase when accident scenarios occur. Shakedown tests were performed prior to installing the optical sensor probe. Due to poor cross-correlation peak values, the probes could not be operated for the bubbly region. Once the determination was made the probes would not be included in as the main measurement of this experiment, high speed cameras were chosen instead. Consequently, high speed cameras were very effective and used as the main measurement device to track bubbles that were visible in the transparent glass upper manifold. In addition, temperature and flow rate were also measured to see the effects of two-phase flow in the WRCCS. Once bulk boiling was established in the WRCCS, there were instabilities in the two-phase flow. Inferences were made in this experiment that these instabilities caused changes in the flowrate of water, velocity of the bubbles, and temperature of the water. Lastly, changing the flowrate of water as dictated by the tank valve position, changed the two-phase phenomena during observation.
Citation
Hodge, Demarkus (2019). Observations and Measurements of Two-Phase Flow Phenomena in a Water-Cooled Reactor Cavity Cooling System During Transient Scenarios. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195930.