Performance Analyses and Evaluation of Co2 and N2 as Coolants in a Recuperated Brayton Gas Turbine Cycle for a Generation IV Nuclear Reactor Power Plant

Abstract

As demands for clean and sustainable energy renew interests in nuclear power to meet future energy demands, generation IV nuclear reactors are seen as having the potential to provide the improvements required for nuclear power generation. However, for their benefits to be fully realized, it is important to explore the performance of the reactors when coupled to different configurations of closed-cycle gas turbine power conversion systems. The configurations provide variation in performance due to different working fluids over a range of operating pressures and temperatures. The objective of this paper is to undertake analyses at the design and off-design conditions in combination with a recuperated closed-cycle gas turbine and comparing the influence of carbon dioxide and nitrogen as the working fluid in the cycle. The analysis is demonstrated using an in-house tool, which was developed by the authors. The results show that the choice of working fluid controls the range of cycle operating pressures, temperatures, and overall performance of the power plant due to the thermodynamic and heat properties of the fluids. The performance results favored the nitrogen working fluid over CO2 due to the behavior CO2 below its critical conditions. The analyses intend to aid the development of cycles for generation IV nuclear power plants (NPPs) specifically gas-cooled fast reactors (GFRs) and very high-temperature reactors (VHTRs).

Analysis of Control-System Strategy and Design of a Small Modular Reactor with Different Working Fluids for Electricity and Hydrogen Production as Part of a Decentralised Mini Grid

“…The conditions for hydrogen production were modelled and simulated using an inhouse tool proprietary to EGB Engineering, which has been used in numerous studies [14][15][16][17][18][19]. The tool calculates each station parameter based on inlet conditions and the reactor core-outlet temperature (COT) in order to determine the NPP power output and cycle efficiency.…”

“…Due to the self-containing nature of the closed-cycle gas turbine, almost all permanent gaseous working fluid can be utilised since the fluid will be operated in the gaseous region beyond its critical temperature all through the cycle [14]. However, selecting appropriate working fluid for the system would depend on meeting several criteria, some of which are dictated by the fluid properties, special requirements of the existing conversion module, and techno-economic considerations.…”

‘Greening’ an Oil Exporting Country: A Hydrogen and Helium Closed-cycle Gas Turbines Case Study

“…The selection of the operational fluid in this cycle carries substantial importance in determining the pressures, temperatures, and overall efficiency of the power plant. The thermodynamic and thermal characteristics of the fluids hold significant relevance in establishing the outcomes of performance [44,46]. The selection of the working medium in inventory control systems for nuclear-powered closed-cycle gas turbines has a notable influence on the design and performance attributes.…”

Feasibility of a Helium Closed-Cycle Gas Turbine for UAV Propulsion

“…To this end, the closed-cycle gas turbine discussed in this paper is coupled directly to a small, very high-temperature reactor (VHTR) cooled by helium working fluid with a core outlet temperature simulated between 700 and 950 °C. With helium as the coolant and cycle working fluid, it brings several benefits such as chemical inertness, single-phase cooling and neutronic transparency, which makes reactivity effect with structural material low [29]. The choice of working fluid also has effects on the turbo set (compressor and turbine) in terms of the number of stages for the attainment of the required pressure ratio, high cycle efficiency and machine size.…”