Experiment on Pool and Flow Boiling CHF for the SiC Surfaces under Atmospheric Condition

The study has been performed with SiC surfaces under pool boiling condition and flow boiling condition. Under pool boiling condition, CHF of the SiC-coated stainless steel plate and the bare stainless steel plate have been compared. In flow boiling experiment, CHF of the α-SiC tube has been taken, and it was compared with the bare stainless steel tube. Both experiments have shown that SiC surface shows better heat transfer performance than that of the stainless steel surface. Also, considering that the roughness of the coating was almost similar with that of the stainless steel plate, we concluded that at least SiC surface will show equal or even better heat transfer performance in the real situation. After the Fukushima accident in Japan, hydrogen explosion problem has been highlighted so far. There have been many studies regarding steam and water reaction to mitigate the hydrogen explosion. For materials of light water reactor (LWR) cladding, neutron absorption should be quite low for the neutron economy, and the reaction rate should be low for the integrity of the system. From many candidates, SiC has been used in this study. Many previous studies focused on the application of the SiC to the LWR cladding. However, up to now, we thought that the most applicable and usable method for the application of SiC is SiC coating on the present Zircaloy cladding. In this aspect, we suggest PVD (Physical Vapor Deposition)-sputtering on the Zircaloy cladding. Critical heat flux (CHF) is very important value for the thermal hydraulic phenomena. CHF is affected by many factors such as the material property, morphology, and liquid property. Previous studies have confirmed the factors affecting on the CHF