To response to the increasing demands for clean water, a large pressurized water reactor (PWR) with a desalination capability has been studied and demonstrated its potential so far. However, the electricity production of the large nuclear reactor decreases by 10% due to steam bypass for desalination. In this study, the authors evaluate the possibility of a large PWR with a capability of producing both electric power and clean water by using the supercritical CO2 (S-CO2) Brayton cycle technology. The S-CO2 power technology is adopted to minimize the decrease in the electricity production capacity due to desalination process. Two concepts which replace the existing steam based power conversion system with a S-CO2 Brayton cycle were proposed. The first concept is that the low pressure steam turbine section of the power conversion system is replaced with the S-CO2 Brayton cycle. The second concept is that the whole steam based power conversion system is replaced with the S-CO2 Brayton cycle. Several S -CO2 cycle options were considered in terms of power production and the desalination capacity and conducted a comparative analysis of selected layouts and the optimal operating conditions of the suggested layouts were identified. (C) 2017 Elsevier B.V. All rights reserved.