Role of sea salt deposition on the advances in pool boiling heat transfer in nuclear reactors
Shikha A. Ebrahim, Emil Pradeep, Mansour Ahmed
Abstract
The study of pool boiling performance of seawater and its advancements in the field of nuclear power safety is given significant importance in the Arabian Gulf (AG) region. The literature covers very limited data regarding the heat transfer capabilities of seawater collected from the AG region. This work investigates the transient pool boiling characteristics of natural seawater using cylindrical zirconium rods. Five successive quenching experiments were performed using distilled water and natural seawater coolants at saturated temperature and atmospheric pressure. Natural seawater was collected from the Doha Power Station, located along the AG coast of Kuwait. The chemical composition, pH, total dissolved solids (TDS), and electrical conductivity (EC) of the collected seawater were examined. By plotting the quenching and boiling curves, the cooling performance was evaluated based on minimum film boiling temperature (Tmin) and critical heat flux (CHF). The results revealed a remarkable boiling heat transfer enhancement, with Tmin and CHF increasing up to 25% and 93.6% in the fifth experiment, respectively. Subsequently, the surface morphology of the rods before and after quenching in each liquid coolant was characterized in detail. The surface characterization results justified the augmentation in heat transfer caused by quenching in seawater coolant. The boiling visualization images were presented at different time frames to visually support the enhancement mechanism. Surface wettability results were illustrated to understand the influence of surface porosity on the spreadability of liquid droplets. A novel hypothesis on the mechanism of sea salt deposition and its impact on destabilizing the vapor layer in the film boiling regime was proposed. The findings of this study are anticipated to be beneficial in improving the safety margins for in-vessel retention of the fuel rods in nuclear power plants.