Rapid cooling performance of zirconium rods quenched in natural seawater

Abstract

The viability of using natural seawater as an effective working coolant to ensure safe and efficient cooling mechanism is a significant study in the Arabian Gulf region. This study investigates transient pool boiling characteristics of natural seawater collected from different locations in the Arabian Gulf coast of Kuwait, compared to the baseline case of distilled water. Seawater samples are collected from prime locations (Shuwaikh, Al Zour, and Doha ports), which are highly capable of accommodating upcoming power plants and nuclear reactors. Extremely heated vertical zirconium rods are quenched in saturated pools at atmospheric pressure. A detailed study of the seawater samples is carried out through semi-quantitative calculation (SQX) results to evaluate the elemental composition, and water quality comparisons are made based on pH, total dissolved solids, and conductivity. The cooling performance is monitored by plotting the quenching and cooling rate curves, and evaluated based on the minimum film boiling temperature ( Tmin) and maximum cooling rate. The results demonstrate an excellent improvement in Tmin and maximum cooling rate by employing natural seawater collected from Al Zour, which is located in the southern part of Kuwait. A minimum of 10% increase in Tmin is depicted by Al Zour seawater. The enhancement is attributed to the salt deposition activity caused by sudden evaporation of seawater on the surface. The salt deposits destabilize the vapor film to promote early vapor film breakage and act as an additional nucleation site to initiate early nucleate boiling, leading to an efficient cooling performance. Seawater collected from Shuwaikh port demonstrates a negative influence on the effective change in Tmin. A detailed examination is carried out on the surface of zirconium samples with the help of wavelength dispersive x-ray fluorescence analysis and SQX analysis, to identify and evaluate the prime elements responsible for the enhanced cooling performance. This study proves that even though the seawater is collected along the same coast, its characteristics differ when utilizing it in cooling systems.