The main purpose of the study is to develop more safe, advanced and applicable method for cladding in Light Water Reactor (LWR). The phenomenon of active hydrogen production from Zircaloy's active interaction with steam and thus active corrosion under steam condition can induce disastrous result considering back on the Fukushima accident. SiC has much lower potential for the hydrogen explosion and even has lower neutron absorption cross section which is one of required characteristics for the nuclear reactor cladding candidates. In addition, since SiC has high thermal conductivity that near the critical heat flux (CHF), heat can be transferred axially and danger for disruption of cladding is reduced. Since SiC is ceramic, it is fragile and there exists possibility of break at normal nuclear reactor operation condition. Therefore, to minimize interaction between the cladding and the coolant, SiC coating through physical vapor deposition (PVD)-sputtering on the surface of Zircaloy-4 cladding was our idea. In our first study, to assess thermal property, pool boiling in saturated de-ionized (DI) water with SiC-coated surfaces for two kinds of thickness has been performed. The scanning electron microscope (SEM) images showed the reason for the CHF results. In the second experiment, flow boiling with subcooled water on α-SiC pipe has been studied. Measured CHF was 3.01 MW/m~2. For the comparison, CHF from two correlations, Weber-Johannsen and KAIST (1995), have been used. α-SiC of rough surface showed better heat transfer performance over the results achieved from the two correlations.
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