Abstract
The Supercritical Water Reactor (SCWR), one of the six possible types of Gen-IV reactor, is a Light Water Reactor (LWR) operating at supercritical pressure. It has the advantage of high thermal efficiency, plant system simplifications and proven technologies. In this study, RELAP5/MOD3 code is used to simulate the steady state of the SCWR and to analyze the transients. The components considered in the input deck include SCWR core, 2 loop hot legs, cold legs, and safety components. Analyses have shown that a transient caused by a Loss of Main Feedwater (LOMF) event can be a challenging event for a SCWR. The propose of the safety system is to make the peak cladding temperature remain less than the transient limit 840℃. Due to some defect of the heat transfer model of RELAP5/MOD3 code, the transient analyses are not complete.