Boric acid and boiling time effects on critical heat flux for corrosive and non-corrosive materials

Abstract

BA (Boric Acid)-added coolant used for severe accident mitigation strategies (IVR-ERVC and core catcher) induces dissolution of heated surfaces during corrosion process; metal ion or particle concentrations inside the coolant increase with the corrosion process. In this study, various states of BA-added working fluids are considered for both corrosive and non-corrosive test sections. Before each experiments, the fluid conditions are made by the corrosion of carbon steels (not for the experiments) immersed in the BA-dissolved de-ionized (DI) water; metal elements dissolves with time. For the non-corrosive test section, CHF values increase with the metal oxide particles in the coolant where particle deposition occurs. In comparison, for the corrosive test section, CHF is strongly affected by boiling times. For relatively short boiling times, the enhancement is much more noticeable than the longer ones; degradation of CHF values are sometimes observed for the latter condition.