Power Plant Technology Research Articles

Recent Advances in Computational Convective Heat Transfer Study in a Sub-Channel for Nuclear Power Reactor and Future Directions

A nuclear power reactor's primary use is to generate thermal energy, which in turn produces electricity. The primary heat source is a nuclear fission event occurring inside the fuel rod. The convection heat is transmitted through the coolant by the heat energy generated at the fuel rod wall boundary. Better heat transfer is produced in the flow area by turbulence and irregularity. As a result, turbulent flow heat transfer may present a significant challenge when predicting and assessing the thermal performance of nuclear power reactors. Computational techniques in convective heat transfer have become indispensable for solving challenging issues in the fields of science and engineering thanks to the development of current sophisticated numerical methods and high-performance computer hardware. The development of novel computational techniques and models for complicated transport and multi-physical phenomena is constantly in demand throughout applicable disciplines. This chapter's objective is to provide some recent developments in computational techniques for convective heat transfer, taking into account research interests in the community of mass and heat transfer, and to showcase relevant applications in nuclear power plant engineering domains including future directions. This study describes the most recent advancements in nuclear reactor convective heat transfer research utilizing the computational fluid dynamics (CFD) method, particularly at Ansys Fluent. This work examines the convective heat transfer and fluid dynamics fluid dynamics for turbulent flows across three rod bundle sub-channels that are typical of those employed in the PWR-based VVER type reactor. In this paper, CFD analysis is carried out using the software tool Ansys Fluent. Temperature distribution profile, velocity profile, pressure drop, and turbulence properties were investigated in this study. Boundary conditions i.e. temperature, velocity, pressure, heat flux, and heat generation rate were applied in the sub-channel domain. The main obstacles and bright spots for the CFD methods in nuclear reactor engineering are discussed, which helps to further its further uses. We intend to research a full-length fuel bundle model for VVER-1200 in the future to gather specific fluid characteristic data and use the findings to analyze safety and operate nuclear power facilities in Bangladesh. This paper presents a thorough analysis of the sub-channel thermal hydraulic codes used in nuclear reactor core analysis. This review discusses several facets of previous experimental, analytical, and computational work on rod bundles and identifies potential future directions based on those earlier studies.

Integrated Research Progress on Desulfurization, Denitrification, and Decarbonization Technologies in Coal-Fired Power Plants

Integrated Research Progress on Desulfurization, Denitrification, and Decarbonization Technologies in Coal-Fired Power Plants

Comparative assessment of the environmental impact of nuclear power plant technology using life cycle assessment approach: A review

Nuclear power plants (NPP) are being considered as an alternative energy that could reducing greenhouse gas emissions. However, there are various challenges that need to be addressed regarding the variation of current nuclear technology such as environmental impact issues. To ensure the sustainability and effectiveness of nuclear power plants technology, a Life Cycle Assessment (LCA) approach can be used to study the environmental impacts of the nuclear power plant. LCA is a method for evaluating the environmental impact of a product or process from start to finish. By conducting a preliminary LCA study of each Nuclear Power Plant technologies, the environmental impacts of the stages of construction, operation, and management of radioactive waste can be understood. This study can also help compare the environmental impacts of nuclear power plants with other energy technologies. This preliminary study will review the environmental impact from pressurized water reactor, boiling water reactor, molten salt reactor, and compare with conventional coal power plant to provide compact summary of the technology. The results of the LCA study can help identify areas that require more attention in the development of nuclear power plants in Indonesia.

Review of SCWR research in Japan

SCWR (supercritical water cooled reactor) is one of the Generation IV reactors. This review summarizes the results of SCWR design concept development through numerical simulations carried out by the author-led team at the University of Tokyo and Waseda University from 1989 to 2014. They are core design, subchannel analysis, statistical thermal design, fuel rod design, development of fuel integrity criteria, plant system and heat balance, plant dynamics analysis, plant control, startup system, stability analysis, safety principle, safety criteria, safety analysis, transient subchannel analysis and fast reactor SCWR. A brief summary of experimental results on thermal hydraulics, materials and water chemistry follows. Discussion includes SCPR study by Japanese BWR manufacturers, comments on the 2005 INEEL SCWR report, misconceptions about SCWR and commercialization challenges. The SCWR is an innovation in light water reactors based on supercritical coal-fired power plant technology that has been in use worldwide for over half a century. This review covers most of the SCWR design and analysis. For researchers, it is a good subject to understand the design and analysis of light water reactors.

Improving power plant technology to increase energy efficiency of autonomous consumers using geothermal sources

Abstract The significance of this study is underscored by the immense potential of binary power plants in the contemporary world. These plants have a pivotal role to play in supplying heat to homes, facilitating greenhouse heating, and supporting air conditioning systems. The purpose of the study is to provide recommendations on eliminating errors in the processes of improving and implementing geothermal plants and analysing their functioning during electricity generation. The analytical method, classification, functional, statistical, synthesis, and others should be noted among the methods used. The features of geothermal plants in Kazakhstan were noted, their differences were analysed, and errors that are made during the operation of power plants to increase the energy efficiency of consumers and the causes of errors were analysed. Uncertainties in the development and their impact on the functioning of geothermal power plants were identified. The practical value lies in the application of the identified results, solving errors in the development and implementation of a binary power plant to improve the energy efficiency of consumers, the reliability of the use of geothermal plants in the region, considering various factors, which will help provide recommendations for the appropriate use of the mechanism.

Scope of conceptual development of Resilient supercritical Light water-cooled reactor (SCWR-R)

The research and development (R&D) of Supercritical Light Water-cooled Reactor (SCWR) has been based on the matured Generation III light water-cooled reactor (LWR) technology and the supercritical fossil fuel-fired power plant (SC-FPP) technology. The plant concept has unique features such as the simple and compact plant system and the high thermal efficiency. Currently, the Japanese concepts are being further developed at Waseda University with focuses on improving resilience of SCWR. This study proposes and presents the overall scope of the new Resilient SCWR (SCWR-R) concept with focuses on two viewpoints: (1) SCWR can utilize variety of different core designs ranging from thermal to fast spectrum for multi purposes (e.g., Pu breeding, Minor Actinide burning) with the same plant system to respond to different fuel cycle needs; (2) severe accident management of SCWR-R can be developed with the combination of IVR and PCV with S/C to minimize the PCV internal contamination by radioactive materials, which should greatly reduce post-severe accident management. To establish the SCWR-R concept, the multi-level physics simulation methodology is currently being developed to evaluate the debris criticality, cooling and radioactive aerosol management during the severe accident.

Harmonized geospatial data to support infrastructure siting feasibility planning for energy system transitions

Climate change, energy system transitions, and socioeconomic change are compounding influences affecting the growth of electricity demand. While energy efficiency initiatives and distributed resources can address a significant amount of this demand, the United States will likely still need new utility-scale generation resources. The energy sector uses capacity expansion planning models to determine the aggregate need for new generation, but these models are typically at the state or regional scale and are not equipped to address the wide range of location- and technology-specific issues that are increasingly a factor in power plant siting. To help address these challenges, we have developed the Geospatial Raster Input Data for Capacity Expansion Regional Feasibility (GRIDCERF) data package, a high-resolution product to evaluate siting suitability for renewable and non-renewable power plants in the conterminous United States. GRIDCERF offers 264 suitability layers for use with 56 power plant technologies in a harmonized format that can be easily ingested by geospatially-enabled modeling software allowing for customization to robustly address science objectives when evaluating varying future conditions.

Wet removal of elemental mercury by acid-assisted electrochemical oxidation method

As a global pollutant, mercury emission is increasingly restricted in recent years. It is urgent to explore a new and efficient mercury removal technology for coal-fired power plants. A new acid-assisted electrochemical oxidation (AEO) technique for mercury removal was proposed using platinum plate as cathode and fluorine-doped tin dioxide (FTO) glass as anode. The effects of acid type, acid concentration, applied direct current (DC) voltage, electrolyte type, SO2, NO and O2 on the Hg0 removal efficiency were carried out. The results indicated that the mercury removal efficiency increased with the increase of DC voltage and nitric acid concentration. When the concentration of nitric acid increased to 0.15 mol/L, the mercury removal efficiency remained unchanged. SO2 and NO inhibited the removal of Hg0 in AEO system, but the inhibition was reversible. Compared with the mercury removal efficiency under single experimental conditions, the mercury removal efficiency of electrochemical oxidation can reach 96% under the experimental conditions of 0.1 mol/L nitric acid and 4V DC voltage, suggesting that the synergistic effect of nitric acid and DC voltage plays a key role. According to the experimental results, the mechanism of Hg0 removal in AEO system was analyzed. At the anode, Hg0 was oxidized by hydroxyl radical (.OH) generated by the oxidation reaction on the anode surface. At the cathode, dissolved oxygen or O2 adsorbed on the surface of Pt is reduced to form anionic superoxide radicals (.O−2). Moreover, parts of .O−2 would produce .OH with the aid of electron at acidic condition. Free radicals capture experiments showed that .O−2 and .OH were the main active substances for the removal of Hg0 by acid-assisted electrochemical method. The research is helpful for the development of effective electrochemical techniques for industrial mercury removal and recycling of industrial acid waste.

Identifying and quantifying a complete set of full-power initiating events during early design stages of high-temperature gas-cooled reactors

Identifying initiating events is the first step in building a probabilistic risk assessment model. The history of commercial nuclear power plant is primarily light-water reactors, hence, a comprehensive set of possible initiating events that covers most available light-water reactors is identified allowing for a frequentist approach to estimating their associated frequencies. However, other technologies of nuclear power plants do not share the same operating experience, hence, there are no comprehensive lists of initiating events for non-light-water reactors. This paper presents an approach that utilizes top-down deductive methodologies, master logic diagrams, and heat balance fault trees; the bottom-up inductive methodology of failure modes and effects analysis; and legacy and contemporary information to identify a complete list of initiating events for the Xe-100 high-temperature gas-cooled reactor (HTGR). Moreover, the paper presents the approach on how to estimate the frequencies using legacy sources along with deterministic analysis and fault trees. Furthermore, the paper presents an approach to estimate uncertainty parameters associated with each of these initiating events using constrained non-informative distributions to account for lack of operating experience. Finally, the paper presents the list of identified initiating events for the Xe-100 along with their frequencies and uncertainty parameters which serves, along with other contemporary sources, as another building block in having a comprehensive set of initiating events for HTGRs.

Techno-Economic Analysis of Hydrogen–Natural Gas Blended Fuels for 400 MW Combined Cycle Power Plants (CCPPs)

Various research and development activities are being conducted to use hydrogen, an environmentally friendly fuel, to achieve carbon neutrality. Using natural gas–hydrogen blends has advantages such as the usage of traditional combined cycle power plant (CCPP) technology and existing natural gas piping infrastructure. Therefore, we conducted CCPP process modeling and economic analysis based on natural gas–hydrogen blends. For process analysis, we developed a process model for a 400 MW natural gas CCPP using ASPEN HYSYS and confirmed an error within the 1% range through operation data validation. For economic analysis, we comparatively reviewed the levelized cost of electricity (LCOE) of CCPPs using hydrogen blended up to 0.5 mole fraction. For LCOE sensitivity analysis, we used fuel cost, capital expenditures, capacity factor, and power generation as variables. LCOE is 109.15 KRW/kWh when the hydrogen fuel price is 2000 KRW/kg and the hydrogen mole fraction is increased to 0.5, a 5% increase from the 103.9 KRW/kWh of CCPPs that use only natural gas. Economic feasibility at the level of 100% natural gas CCPPs is possible by reducing capital expenditures (CAPEX) by at least 20%, but net output should be increased by at least 5% (20.47 MW) when considering only performance improvement.

Wind power plants hybridised with solar power: A generation forecast perspective

The association of different variable renewable technologies in hybrid power plants and the benefits of their aggregation for the operation of power systems is an area of recent research. Accurate forecasts are crucial for extracting those benefits and promote an optimal integration of such plants into power systems and electricity markets. This study focuses on the hybridisation of existing wind power plants with different shares of solar photovoltaic capacity and investigates how these power plants can reduce their combined forecast errors and thus, increasing profitability in electricity markets.The work uses a forecast methodology based on a sequential forward feature selection algorithm which employs two different objective functions and an artificial neural network approach previously presented but, in this case, it is applied to the specific case of hybrid power plants. The methodology uses as input data from a numerical weather prediction model and iteratively selects meteorological features to achieve the different objective functions implemented, namely i) minimisation of the root mean square error; or ii) maximisation of the market remuneration.The methodology developed was applied to three case studies in Portugal with different levels of wind and solar generation complementarity. The results show that the hybrid power plants can increase market value by up to 5% and total remuneration can increase by up to 30% when compared with the existing wind power plant, while it is possible to reduce the forecast errors by nearly 4%. The obtained results highlight the need to select the most relevant meteorological features to maximise the accuracy of the power forecast and the renewable power producers revenues in a market environment.

Handling heat‐stable salts in post‐combustion CO2 capture: A detailed survey

AbstractThe generation of heat‐stable salts (HSSs) in alkanolamine solutions for CO2 capture processes, which is adapted for power plant technologies, exists irrespective of the class of amine solution used for the capture process. Their presence do not only trigger decrements in the CO2 absorption capacities of the solvents and contribute to further alkanolamine degradation, but also result in foaming and loss of solvents, which impacts system economics and threatens the environment. HSSs also promote the corrosiveness of the metallic structures of capture systems by lowering the pH and increasing the conductivity of the absorbent solutions. Overall, these effects substantially subvert the reliability and integrity of CO2 capture units. This survey affords sufficient background on the existence of HSSs by unraveling the flow process in a typical alkanolamine‐based CO2 capture unit with respect to their formation points and potential threats. Furthermore, the major HSSs removal and alkanolamine reclamation methodologies (electrodialysis, distillation, ion exchange, electromagnetic separation, and solvent extraction) were comprehensively explored. We believe that this review paper will benefit researchers across disciplines as we continue to explore new and complex solvent formulations to minimize the cost of CO2 capture while maximizing efficiency. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

ПЕРСПЕКТИВИ ВПРОВАДЖЕННЯ МАЛИХ МОДУЛЬНИХ РЕАКТОРІВ В ЕНЕРГОСИСТЕМІ УКРАЇНИ

Ukraine's declared goals of sustainable, environmentally acceptable energy development, and reduction of greenhouse gas emissions in accordance with the Paris Agreement require the preferential development of nuclear and renewable energy. At the same time, in the conditions of the current shortage of maneuverable capacities, the increase of stochastic generation volumes from renewable energy sources in the power system and the decommissioning of maneuverable coal-fired power units in accordance with international environmental obligations determines the need to study the possibilities of implementing new nuclear power plant technologies in the IPS of Ukraine, which will be able to participate in daily maneuvering. The article provides an overview of the state of development and implementation of the first NPP projects with small modular reactors of the American companies NuScale Power and Holtec International. It is shown that the national nuclear legislation does not single out MMR as a separate group of nuclear installations and does not take into account their features, which makes it necessary to carry out a thorough professional comparative analysis of the current regulatory framework of Ukraine and other countries on this issue, based on the results of which a decision should be made regarding the need to develop special regulatory requirements for MMR and determine the scope of application of existing regulatory documents. The results of the calculations of the forecast structure of generating capacities of IPS of Ukraine for the period up to 2040 are given, which showed that the construction in Ukraine of 3 powerful advanced NPP power units and the introduction of 1.5 GW of the power units with MMR, which can be used in daily power change modes, with the using of 13 GW of the baseload existing nuclear power units while reducing the capacity of existing coal-fired power units to 5 GW with their reconstruction to meet the requirements of the National Emission Reduction Plan and the growing volume of renewable generation are able to ensure the power balance system and reduce pollutant emissions by at least 50% and greenhouse gases by up to 30%. Keywords: small modular reactor, technical standards, legal and regulatory framework, power system, operating mode.

A review on basic theory and technology of agricultural energy internet

AbstractIn the context of modern agricultural production mode and domestic energy consumption, profound changes have taken place in agricultural and rural energy consumption, resulting in the demand for new technology development in various sectors of source, network, and load in rural energy systems. Agricultural energy internet (AEI) has promoted the development of renewable energy and agricultural electrification in villages. The construction of the AEI is crucial for achieving the synergistic development of agriculture, energy, and environment. The basic theory and key technologies of AEI are investigated and the prospects for the direction of agricultural energy technology are conducted. The research investigation shows that the AEI framework proposed by China Agricultural University is of great significance for realizing agricultural electrification and reducing agricultural carbon emissions. The article describes in detail the key data and characteristics of agricultural electrification loads. Digital twin technology and virtual power plant technology will be crucial to the construction of advanced AEI.

Electricity transportation using HVDC technology for Algerian southern sun power plants

Electricity transportation using HVDC technology for Algerian southern sun power plants

Impact of adaptive water-saving and phaseout strategies on water withdrawal in China's coal-fired power industry under carbon constraints

Coal-fired power generation occupies a dominant position in China's power sector and is known for its high water requirement. Limited research exists on how water withdrawal for coal-fired power generation responds to policy and technical factors, as well as spatial variations in the future. To address this gap, this study utilizes a geospatial dataset at the coal-fired power unit level and an improved calculation method for water withdrawal to investigate the evolving trend of water withdrawal in coal-fired power generation, considering the influences of carbon emission reduction, adaptive water-saving measures, and phaseout strategies. The results demonstrate that the improved water withdrawal calculation method yields superior simulation outcomes compared to existing approaches. The study reveals substantial variations in coal-fired power generation under different carbon emission reduction scenarios. Despite the business-as-usual (BAU) scenario where coal-fired power generation continues to dominate the power sector, implementing various adaptive water-saving scenarios results in national water withdrawal estimates ranging from 42.9 to 59.4 billion m3 in 2050. In contrast, water withdrawal is reduced by 37.6% to 42.9% under the 2.0℃ target scenario and by 86.5% to 97.5% under the 1.5℃ target scenario. Technological advancements play a crucial role in reducing water withdrawal for coal-fired power generation, particularly in northwest China. The transformation of cooling systems significantly decreases water withdrawal nationwide and in the regions that predominantly relied on once-through cooling. The deployment of carbon capture and storage (CCS) technology in coal-fired power plants in the northwest region creates short-term pressure on regional water resources. Under strict carbon emissions constraints, adopting the phaseout strategy with guaranteed lifetime results in relatively higher water withdrawal for coal-fired power generation, and the variations in coal-fired power plants configuration across provinces lead to different responses in water withdrawal changes when facing the same unit retirement strategy.

Two-dimensional Euler grid approximation method for multi-droplet motions

Multi-droplet motion in gas flow is a significant two-phase flow in nuclear power plant, chemical industry and environmental engineering. In contrast to droplet generation and collision in microscopic view, multi-droplet motion presents both macroscopic interaction with gas flow and microscopic single droplet motion characteristic. To simulate the multi-droplet motion, we presented the Euler grid approximation method to update the multi-droplet imformation in all nodes under each calculation step, and constructed a criterion about droplet velocity and direction to ensure droplet motion limited on grid nodes without loss of accuracy. The novelty of this method lies in its description of the virtual streamlines of multiple particles in the same state, as well as the discontinuous flow field composed of these virtual streamlines, furthermore, this method is independent of the time step and can simultaneously calculate droplet information of the entire field. Meanwhile, this paper focuses on the two-phase gas-liquid flow in the gravity separation space of the rotary vane separator, and the motion behavior of multiple droplets in the flow field is simulated based on the parameters of the actual steam-water separator.The result shows that the droplets tend to gather towards the center of the main stream, which is the focus area for droplet separation, and the position with higher density may be the point where the droplets collide. The model can be adopted to calculate the separation efficiency in the process of multi-droplet motion in the gravity separation space, rotary vane separator and other steam separation devices, and the results will help guide the optimal design of the separation device structure.

Thermal performance investigation of the newly shaped vacuum tubes of parabolic trough collector system

The parabolic trough collector (PTC) system is currently the most mature technology for concentrator solar power (CSP) plants. However, the huge radiative heat loss under high temperatures is one of the major obstacles restricting its thermal efficiency and development to the higher temperature. To reduce the radiative heat loss, this study proposes a newly shaped tube (NS-tube) with flatted upper and lower surfaces based on the Negative thermal-flux region theory. By considering different opening angles and tracking errors of the shaped tubes, an optical simulation is developed to analyze the heat flux distribution, and a heat transfer model is established to investigate the heat loss and thermal efficiency. Results show that the thermal efficiency of the NS-tube with optimum opening angles can be improved by 0.62%–4.64% compared to the original tube. The improvement effect is more obvious at high operating temperatures and low Direct Normal Irradiance. Additionally, the thermal stress variation is also analyzed by Ansys fluent. The result shows that the thermal stress of the NS-tube is even smaller than that of the original tube due to the uniform thermal flow effect caused by the flattened lower surface.

Thermodynamics analysis of the supercritical CO2 binary mixtures for Brayton power cycles

Supercritical CO2 Brayton-based cycles are a promising technology for concentrated solar power plants. Their high efficiency can be improved by using CO2 mixtures as working fluid instead of pure CO2. This work studies 3 cycle topologies: simple recompression (RCC), recompression with main compressor intercooling (RCMCI) and partial cooling recompression (PCRC), across a range of regenerator conductance (UA), compressor and turbine inlet temperatures. Each topology is simulated with different working fluids: CO2, CO2–NH3, CO2–SO2, CO2–COS and CO2–H2S. The influence of the working fluid, operating conditions and cycle irreversibility on the overall efficiency has been analyzed in depth, finding two interesting, opposing trends. The mixtures with higher critical pressure improve the heat absorption and rejection temperatures of the cycles, but also increase irreversibility. The combination of topology and mixture that achieves the best compromise between both trends will have the higher efficiency. In general, using RCMCI instead of PCRC or RCC can improve efficiency by up to 4% depending on the working fluid and operating conditions. Using a mixture instead of pure CO2 by up to near 3%.

Review of operations for multi-energy coupled virtual power plants participating in electricity market

The application projects of traditional virtual power plants generally have some significant problems, such as single energy structure, insufficient participation in the market, sparse energy coupling relationship and lack of new loads, which lead to poor operation stability, low economic benefits and difficult risk management of traditional virtual power plants. With the development of distributed energy resources such as electric vehicles, air conditioners, and electric heating loads and the advancement of information and communication technologies, virtual power plants have gradually evolved from aggregating a single type of energy resource to having the ability to meet the aggregation and management of multiple types of energy resources. Virtual power plant technology provides an effective means to aggregate distributed energy and user-side resources to participate in energy market transactions. A virtual power plant with multiple energy sources such as electricity, heat and gas coupling can effectively avoid the lack of system stability and security caused by a single resource structure, and effectively meet the needs of users for multiple types of energy. This paper focuses on multi-energy coupled virtual power plants, summarizes the current status of research on multi-energy coupled virtual power plants participating in power market operation from the aspects of multi-energy coupling mechanism and operation optimization in power market, and finally provides an outlook on the research direction of multi-energy coupled virtual power plants.