Prediction of critical heat flux (CHF) for the high-pressure region in uniformly heated vertical round tubes

Abstract Supercritical coolant cooled reactors may experience the high subcritical pressure region during pressurization or depressurization transients, where the occurrence of the boiling crisis phenomena cannot be avoided. Therefore, a prediction model of CHF for the high-pressure region is required for the design of the supercritical system, but it is still missing. The CHF databank with reduced pressure above 0.7 was compiled from literatures or experiments carried out in IATF, including three different fluids (water, R12, and CO2). With the knowledge of the two-phase phenomena, we rearranged the sublayer dryout model for DNB and proposed a new mechanism for dryout. By introducing dimensionless theory, a new CHF prediction correlation with a simple structure but relatively high accuracy was proposed for water and shows a good adaptation to water and non-aqueous fluids. As illustrated, the new model can be implemented to safety analysis of supercritical systems.