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Selection of Planning Options of Electricity and Freshwater Cogeneration Method Based on High-Temperature Gas-Cooled Reactor
The lack of fresh water in the world has become a growing concern. As an open-source incremental technology for water resources, desalination has become an important method to solve the global water crisis. Based on the inherent safety, versatility, modularity, and advantages of high-temperature gas-cooled reactors, the Saudi Arabia desalination project is the relying background. This paper proposes a complete solution for the high-temperature gas-cooled reactor power and water coproduction project by selecting a combination of process-proven multi-effect distillation (MED) and reverse osmosis (RO). In the scheme, a tertiary circuit is designed for the isolation of radioactive entities. An innovative comparative analysis of the engineering investment and production costs of different desalination technologies, such as MED and RO, and a comparison of the investment estimates of the “thermal” and “membrane” methods for the production of 10,000 tonnes of fresh water per day are performed. The feasibility and energy efficiency of the multi-effect distillation–reverse osmosis (MED-RO) scheme are presented, demonstrating the feasibility and practicality of the above approach.
Journal Article
Computational Fluid Dynamics Modeling of Single Isothermal and Non-Isothermal Impinging Jets in a Scaled-Down High-Temperature Gas-Cooled Reactor Facility
In the current work, the flow characteristics of single isothermal and non-isothermal jets discharging into the upper plenum of a 1/16th scaled-down high-temperature gas-cooled reactor (HTGR) facility were studied. ANSYS Fluent simulations were carried out in the central plane of the jet water flow and the upper plenum for different Reynolds numbers (Re) ranging from 3413 to 12,819. Then, the statistical jet water flow characteristics, such as the mean velocity, root-mean-square fluctuating velocity, Reynolds stress, and the mean temperature in the upper plenum, were computed and presented. The current study’s results showed that the flow maximum velocity occurred far from the jet inlet. Finally, the temperature profiles were plotted, and it was found that the maximum temperature of the flow occurred close to the plume inlet and after that decreased downstream.
Journal Article
Combining Dual Fluidized Bed and High-Temperature Gas-Cooled Reactor for Co-Producing Hydrogen and Synthetic Natural Gas by Biomass Gasification
Biomass gasification to produce burnable gas now attracts an increasing interest for production flexibility in the renewable energy system. However, the biomass gasification technology using dual fluidized bed which is most suitable for burnable gas production still encounters problems of low production efficiency and high production cost. Here, we proposed a large-scale biomass gasification system to combine dual fluidized bed and high-temperature gas-cooled reactor (HTR) for co-production of hydrogen and synthetic natural gas (SNG). The design of high-temperature gas-cooled reactor biomass gasification (HTR-BiGas) consists of one steam supply module to heat inlet steam of the gasifier by HTR and ten biomass gasification modules to co-produce 2000 MWth hydrogen and SNG by gasifying the unpretreated biomass. Software for calculating the mass and energy balances of biomass gasification was developed and validated by the experiment results on the Gothenburg biomass gasification plant. The preliminary economic evaluation showed that HTR-BiGas and the other two designs, electric auxiliary heating and increasing recirculated product gas, are economically comparative with present mainstream production techniques and the imported natural gas in China. HTR-BiGas is the best, with production costs of hydrogen and SNG around 1.6 $/kg and 0.43 $/Nm3, respectively. These designs mainly benefit from proper production efficiencies with low fuel-related costs. Compared with HTR-BiGas, electric auxiliary heating is hurt by the higher electric charge and the shortcoming of increasing recirculated product gas is its lower total production. Future works to improve the efficiency and economy of HTR-BiGas and to construct related facilities are introduced.
Journal Article
Advanced Structural Materials for Gas-Cooled Fast Reactors—A Review
This review summarizes the development of the Gas-Cooled Fast Reactor (GFR) concept from the early 1970s until now, focusing specifically on structural materials and advanced fuel cladding materials. Materials for future nuclear energy systems must operate under more extreme conditions than those in the current Gen II or Gen III systems. These conditions include higher temperatures, a higher displacement per atom, and more corrosive environments. This paper reviews previous GFR concepts in light of several promising candidate materials for the GFR system. It also reviews the recent development of nuclear power and its use in the peaceful exploration of space. The final section focuses on the development and testing of new advanced materials such as SiCf/SiC composites and high entropy alloys (HEA) for the construction and development of GFRs.
Journal Article
Structural Design Simulation of Bayonet Heat Exchanger for Sulfuric Acid Decomposition
The heat generated in a high-temperature gas-cooled reactor can be used to drive the iodine-sulfur cycle to produce hydrogen. However, the sulfuric acid decomposition step requires a sophisticated sulfuric acid decomposer to increase the decomposition rate. The decomposition of sulfuric acid mainly occurs in the catalytic zone, and the optimization of its structure is very important for increasing the decomposition rate. This study focuses on the structural design of the catalytic zone of the sulfuric acid decomposer unit. The structure with double inner tubes is designed to analyze the influence of the inner tube heat transfer area and the catalytic volume of the annulus region on the decomposition rate. The species transport model is used to predict the proportion of products followed by analysis of the key factors affecting the decomposition rate of the catalytic domain. The results reveal that the new design attains the decomposition temperature requirements and increases the fluid velocity of the inner tube. This in turn promotes the heat transfer effect. The decomposition rate is negatively correlated with the flow rate. Nonetheless, a structure with double inner tubes which have the same total area of inner tube as a structure with a single inner tube has a better optimization effect than a structure which has the same annulus catalytic volume as a structure with single inner tube. It increases the decomposition rate by up to 6.1% while a structure which has the same annulus catalytic volume as a structure with a single inner tube does the same by up to 1.7%. The decomposition rate can be maintained at a relatively high level when the inlet velocity of the current structural design is about 0.2 m/s. This study provides a reference for the engineering design of sulfuric acid decomposer based on the heat exchange area and catalytic volume.
Journal Article
Fatigue Life Analysis of Key Equipment in High Temperature Reactor Considering Nuclear Irradiation
The key equipment of high-temperature gas-cooled reactors is always exposed to nuclear irradiation, while the influence of nuclear irradiation on equipment fatigue life is one of the targets to be studied. Based on the expansion mechanism of fatigue cracks of fracture mechanics, combined with actual material parameters, the critical parts of the equipment, the position and time of occurrence of the working tolerance limit are pre-critically analyzed, and the fatigue life model under the influence of nuclear irradiation are corrected to calculate the influence of nuclear radiation on fatigue life which has certain guiding significance for the estimation of fatigue life of key equipment in high temperature gas cooled reactor.
Journal Article
Development of Two Novel Processes for Hydrogenation of CO2 to Methanol over Cu/ZnO/Al2O3 Catalyst to Improve the Performance of Conventional Dual Type Methanol Synthesis Reactor
Conventional methanol synthesis process (CR configuration) consists of water-cooled and gas-cooled reactors in which methanol and water are condensed inside the gas-cooled reactor which deactivates the catalyst. In this study, two novel configurations (AW and ACW configurations) are represented to address this problem in which the gas-cooled reactor is replaced with adiabatic reactor. Moreover, a condenser is applied between adiabatic and water-cooled reactors in ACW configuration. Results show that temperature increases somewhat along the adiabatic reactor that prevents gas condensate formation. Besides, the adiabatic reactor maximum temperature is less than that of first reactor in CR configuration which prevents copper based catalyst thermal sintering. Moreover, a high cross section-to-length ratio of the adiabatic reactor leads to negligible pressure drop along the reactor and improvement in CO2 conversion to methanol that has positive environmental effects. Also, water mole fraction decreases along the reactors of AW and ACW configurations to prevent the deactivation of catalyst active sites. Eventually, methanol production rates by AW and ACW configurations are improved around 25.5% and 43.1% in comparison with CR configuration. So, novel AW and ACW configurations provide many benefits including improvement in catalyst activity and durability, CO2 conversion, and the methanol production rate.
Journal Article
Safety Features of High Temperature Gas Cooled Reactor
The fuel, core structure, and coolant in HTGR can all withstand high temperature. [...]HTGR can provide high temperature output for high efficiency electricity generation and wide range of process heat applications, including hydrogen production. The maximum core temperature after accident is limited by the accumulation of residual heat, which is proportional to the power density during normal operation and to the temperature limit that the integrity of TRISO fuel is ensured to retain all fission products in all accident conditions, with enough margin. [...]it is a very simple solution. Neither massive fuel degradation nor core melt will be possible. [...]it provides a very good foundation for radioactive retention. For radioactive retention, it is also very straightforward for modular HTGR. Because the possibility of massive fuel degradation is physically eliminated, almost all the fission products are retained inside the coating of TRISO particle in normal operation and accident condition.
Journal Article
Development of Analytical Procedures for Chemical Characterization of Substrates for the Production of TRISO Coated Particles as Nuclear Fuel in High Temperature Gas-Cooled Reactors
High temperature gas-cooled reactors have recently gained importance as a source of electricity and process heat. Nuclear fuel used in these reactors consists of TRISO (TRiple coated ISOtropic) coated particles, where spherical grains of UO2 or UC2 or UCO kernel are covered with four successive layers consisting of pyrolytic carbon and silicon carbide. Of great importance is the chemical purity of reagents and substances used for the production of TRISO coated fuel particles. Analytical techniques ensuring the determination of elements at trace levels are inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). They were applied in this work for the chemical characterization of substrates used for TRISO fuel production. Two analytical procedures were developed: the first, where materials are analyzed using ICP-MS, and the second with the aid of NAA. Successive stages of these procedures are described with details. Results of quantitative chemical analysis of examined substances are reported as well as detection limits for the investigated elements. Moreover, the expanded uncertainties estimated for the determined elements while employing the devised analytical procedures are presented.
Journal Article