Abstract: The supercritical water cooled reactor (SCWR) is essentially light water reactor (LWR) operating at higher pressure and temperature beyond the thermodynamic critical point of water (374 ℃, 22.1 MPa). Compared to current generation LWR, the efficiency of a SCWR can approach 45%. With operation beyord the critical pressure the coolant remains single-phase throughout the system. Thus, recirculation and jet pumps, pressurizer, steam generators, and steam separators and dryers in current LWR are all eliminated. The main mission of the SCWR is generation of low-cost electricity.