scholarly journals The application of supercritical CO2 in nuclear engineering: A review

2018 ◽  
Vol 10 (4) ◽  
pp. 149-158 ◽  
Author(s):  
Houbo Qi ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
Shengyao Jiang
Keyword(s):  
Supercritical Fluids ◽  
Supercritical Co2 ◽  
Low Cost ◽  
Reactor Core ◽  
Temperature Stability ◽  
Nuclear Industry ◽  
Brayton Cycle ◽  
Nuclear Engineering ◽  
Rapid Progress ◽  
Recompression Cycle

Due to its advantages of low critical pressure and temperature, stability, non-toxic, abundant reserves and low cost, supercritical CO2 becomes one of the most common supercritical fluids in modern researches and industries. This paper presents an overview focusing on the researches of supercritical CO2 in nuclear engineering and prospects its applications in the field of nuclear industry. This review includes the recent progresses of supercritical CO2 research as: (1) energy conversion material in both recompression cycle and Brayton cycle and its applicability in Generation IV reactors; (2) reactor core coolant in the Echogen power system and reactors at MIT, Kaist and Japan, and other applications, e.g. hydrogen production. Based on the rapid progress of research, the supercritical CO2 is considered to be the most promising material in nuclear industries.

scholarly journals Multi-objective optimization on supercritical CO2 recompression brayton cycle using Kriging surrogate model

2017 ◽  
Vol 21 (suppl. 1) ◽  
pp. 309-316
Author(s):  
Lei Sun ◽  
Chongyu Wang ◽  
Di Zhang
Keyword(s):  
Supercritical Co2 ◽  
Thermodynamic Cycle ◽  
Brayton Cycle ◽  
Time Cost ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Research Fields ◽  
Cycle Efficiency ◽  
Recompression Cycle ◽  
Selection Of

Supercritical CO2 cycle has become one of the most popular research fields of thermal science. The selection of operation parameters on thermodynamic cycle process is an important task. The computational model of supercritical CO2 recompression cycle is built to solve the multi-objective problem in this paper. Then, the optimization of parameters is performed based on genetic algorithm. Several Kriging models are also used to reduce the quantity of samples. According to the calculation, the influence of sample quantity on the result and the time cost is obtained. The results show that it is required to improve the heat transfer when improvement of the cycle efficiency is desired.

Supercritical CO2 Cycle for Fast Gas-Cooled Reactors

2004 ◽  
Author(s):  
Vaclav Dostal ◽  
Michael J. Driscoll ◽  
Pavel Hejzlar ◽  
Yong Wang
Keyword(s):  
Specific Volume ◽  
Supercritical Co2 ◽  
Nuclear Power ◽  
Nuclear Reactor ◽  
Attractive Alternative ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Brayton Cycle ◽  
Property Changes ◽  
Recompression Cycle

Brayton cycles are currently being extensively investigated for possible use with nuclear reactors in order to reduce capital cost, shorten construction period and increase nuclear power plant efficiency. The main candidates are the well-known helium Brayton cycle and the less familiar supercritical CO2 cycle, which has been given increased attention in the past several years. The main advantage of the supercritical CO2 cycle is comparable efficiency with the helium Brayton cycle at significantly lower temperature (550°C/823K), but higher pressure (20MPa/200 normal atmospheres). By taking advantage of the abrupt property changes near the critical point of CO2 the compression work can be reduced, which results in a significant efficiency improvement. Among the surveyed compound cycles the recompression cycle offers the highest efficiency, while still retaining simplicity. The turbomachinery is highly compact and achieves efficiencies of more than 90%. Preliminary assessment of the control scheme has been performed as well. It was found that conventional inventory control could not be applied to the supercritical CO2 recompression cycle. The conventional bypass control is applicable. The reference cycle achieves 46% thermal efficiency at the compressor outlet pressure of 20MPa and turbine inlet temperature of 550°C. The sizing of the heat exchangers and turbomachinery has been performed. The recuperator specific volume is 0.39m3/MWe and pre-cooler specific volume 0.08m3/MWe. For the reference 600MWth reactor this translates to ∼ 99m3 heat exchanger core for the recuperator and ∼ 21m3 for the pre-cooler. Overall the cycle offers an attractive alternative to the steam cycle. The supercritical CO2 cycle is well suited to any type of nuclear reactor with core outlet temperature above ∼ 500°C.

Applications of Supercritical Carbon Dioxide Brayton Cycle for Nuclear Engineering

2021 ◽  
pp. 717-760
Author(s):  
Deqi Chen ◽  
Lian Hu ◽  
Feng Jin ◽  
Hao Zeng
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Brayton Cycle ◽  
Nuclear Engineering ◽  
Energy Conversion Systems ◽  
Typical Layout ◽  
Cycle Efficiency ◽  
Recompression Cycle ◽  
Direct Cycle ◽  
Supercritical Carbon

Supercritical carbon dioxide Brayton cycle is attracting increasing attention in various energy conversion systems due to its high cycle efficiency and high compactness. This chapter performs a review about the application of supercritical carbon dioxide Brayton cycle in nuclear engineering. The different cycle layouts developed from the original direct Brayton cycle are presented, in which the recompression cycle is the most typical layout. The thermodynamic analysis approach is discussed for the direct cycle and recompression cycle. Moreover, the key facilities, including heat transfer, compressor, and turbine, are outlined for the application of Brayton cycle in nuclear engineering.

Point Defect Absorption and Dislocation Loop Formation at Grain Boundaries in Hvem-Irradiated Zr and Its Alloys:1. Influence of Solute Addition

1985 ◽  
Vol 43 ◽  
pp. 350-351
Author(s):  
R.A. Herring ◽  
M. Griffiths ◽  
M.H Loretto ◽  
R.E. Smallman
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Point Defect ◽  
Reactor Core ◽  
Solute Concentration ◽  
Nuclear Industry ◽  
Dislocation Loops ◽  
Loop Formation ◽  
Component Material ◽  
Impurity Interaction

Because Zr is used in the nuclear industry to sheath fuel and as structural component material within the reactor core, it is important to understand Zr's point defect properties. In the present work point defect-impurity interaction has been assessed by measuring the influence of grain boundaries on the width of the zone denuded of dislocation loops in a series of irradiated Zr alloys. Electropolished Zr and its alloys have been irradiated using an AEI EM7 HVEM at 1 MeV, ∼675 K and ∼10-6 torr vacuum pressure. During some HVEM irradiations it has been seen that there is a difference in the loop nucleation and growth behaviour adjacent to the grain boundary as compared with the mid-grain region. The width of the region influenced by the presence of the grain boundary should be a function of the irradiation temperature, dose rate, solute concentration and crystallographic orientation.

scholarly journals Recent Advances of Photocatalytic Application in Water Treatment: A Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1804
Author(s):  
Guangmin Ren ◽  
Hongtao Han ◽  
Yixuan Wang ◽  
Sitong Liu ◽  
Jianyong Zhao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Water Treatment ◽  
High Efficiency ◽  
Low Cost ◽  
Great Promise ◽  
Rapid Progress ◽  
Recent Advances ◽  
Photocatalytic Application ◽  
Oxidation Technology ◽  
Performance Challenges

Photocatalysis holds great promise as an efficient and sustainable oxidation technology for application in wastewater treatment. Rapid progress developing novel materials has propelled photocatalysis to the forefront of sustainable wastewater treatments. This review presents the latest progress on applications of photocatalytic wastewater treatment. Our focus is on strategies for improving performance. Challenges and outlooks in this promising field are also discussed. We hope this review will help researchers design low-cost and high-efficiency photocatalysts for water treatment.

Numerical investigation on the performance of impeller back seal configuration in a supercritical CO2 radial-inflow turbine

2021 ◽  
pp. 095440622110095
Author(s):  
Qiuwan Du ◽  
Yuqi Wang ◽  
Di Zhang ◽  
Yonghui Xie
Keyword(s):  
Numerical Investigation ◽  
Supercritical Co2 ◽  
Labyrinth Seal ◽  
Brayton Cycle ◽  
Mechanical Seal ◽  
Nozzle Outlet ◽  
Excellent Performance ◽  
Core Component ◽  
Comprehensive Performance ◽  
Radial Inflow Turbine

Radial-inflow turbine is a core component in supercritical CO2 (SCO2) Brayton cycle. The leakage from the nozzle outlet towards the impeller back brings a great challenge to the efficiency and security of the power system. In this paper, the labyrinth seal (LS) and dry gas seal (DGS) are arranged on the impeller back of a SCO2 radial-inflow turbine and the influence on the comprehensive performance is investigated. Results demonstrate that both LS and DGS configurations can significantly reduce leakage of the impeller back and DGS configuration performs better. Compared with the configuration without leakage, the power and efficiency of DGS configuration are only reduced by 0.27% and 0.35% respectively. The seal clearance and the inlet width have a greater effect on LS configuration. The thermo-mechanical seal deformation values of DGS configurations are all less than 8 μm, which verifies the feasibility. Finally, a novel combined seal configuration with both LS and DGS is proposed and excellent performance is achieved, providing a potential approach for the sealing problem of SCO2 radial-inflow turbine.

Optimization of Supercritical CO2 Brayton Cycle for Simple Cycle Gas Turbines Exhaust Heat Recovery Using Genetic Algorithm

2017 ◽  
Author(s):  
Akshay Khadse ◽  
Lauren Blanchette ◽  
Jayanta Kapat ◽  
Subith Vasu ◽  
Kareem Ahmed
Keyword(s):  
Genetic Algorithm ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Supercritical Co2 ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Brayton Cycle ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost and applicable to a broad range of heat source temperatures. The current study is focused on thermodynamic modelling and optimization of Recuperated (RC) and Recuperated Recompression (RRC) S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using a genetic algorithm. The Genetic Algorithm (GA) is mainly based on bio-inspired operators such as crossover, mutation and selection. This non-gradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio. It also outputs optimized mass flow rate of CO2 for the fixed mass flow rate and temperature of the exhaust gas. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. Further the optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for waste heat recovery.

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