The Impact of Properties on Heat Transfer Coefficients of Alternative Power Cycles

Abstract

Currently, all nuclear-power reactors are connected to SubCritical-Pressure (SubCP) Rankine steam-turbine cycles of various configurations. Due to this the maximum thermal efficiency of Nuclear Power Plants (NPPs) equipped with Advanced Gas-cooled Reactors (AGRs) is 43%, which is the highest efficiency in the nuclear-power industry. However, thermal PPs equipped with combined cycles or SuperCritical Pressure (SCP) Rankine cycles have thermal efficiencies up to 62.5% and 55%, respectively. Therefore, to increase thermal efficiency in the nuclear-power industry alternative power cycles such as combined cycles and SCP Rankine cycles have to be used. These cycles might use the following Working Fluids (WFs): Helium, nitrogen, mixture of He & N₂, SC carbon dioxide (CO₂) – in Brayton cycles and steam, SC Water (SCW), and SC CO₂ in Rankine cycles. Due to this the current paper is dedicated to analyzing the impact of thermophysical properties of working fluids on heat transfer in alternative power cycles.