Power Plant Components Research Articles

Efficient pressure regulation in nonlinear shell-and-tube steam condensers via a Novel TDn(1 + PIDn) controller and DCSA algorithm

Steam condensers are vital components of thermal power plants, responsible for converting turbine exhaust steam back into water for reuse in the power generation cycle. Effective pressure regulation is crucial to ensure operational efficiency and equipment safety. However, conventional control strategies, such as PI, PI-PDn and FOPID controllers, often struggle to manage the nonlinearities and disturbances inherent in steam condenser systems. This paper introduces a novel multistage controller, TDn(1 + PIDn), optimized using the diligent crow search algorithm (DCSA). The proposed controller is specifically designed to address system nonlinearities, external disturbances, and the complexities of dynamic responses in steam condensers. Key contributions include the development of a flexible multi-stage control framework and its optimization via DCSA to achieve enhanced stability, faster response times, and reduced steady-state errors. Simulation results demonstrate that the TDn(1 + PIDn) controller outperforms conventional control strategies, including those tuned with advanced metaheuristic algorithms, in terms of settling time, overshoot, and integral of time weighted absolute error (ITAE). This study marks a significant advancement in pressure regulation strategies, providing a robust and adaptive solution for nonlinear industrial systems.

Mitigating Risks from Counterfeit and Substandard Components in Nuclear Power Plants through Nuclear Quality Management Measures

Mitigating Risks from Counterfeit and Substandard Components in Nuclear Power Plants through Nuclear Quality Management Measures

Impact Load Resistance of Steel after Heat Treatment and Quenching with Distilled Water

Given that low carbon steels have favourable mechanical properties, they are widely used in power plant components, oil and gas pipelines, and armor structures. However, the relationship between a steel's structure and mechanical properties can occasionally be negatively impacted by the existence of ferrite and pearlite phases in its microstructure. One of the most crucial aspects of engineering metallurgy is the heat treatment of steels, which improves a variety of mechanical and physical characteristics that are useful in many structural applications. The heating and cooling of an alloy or metal while it is solid in order to refine its grain size and other properties and create the necessary microstructures is known as heat treatment. This paper will use distilled water as a cooling medium at various temperatures to perform repeated heat treatments. Comparing the impact load resistance of the original and treated specimens is the goal, as is the impact of multiple heat treatments and the use of distilled water as a medium for cooling at different temperatures. The findings of an Excel program study show that the heat-treated samples had a greater impact resistance value than the untreated ones. The strong martensitic network alloys created by heat treatment procedures are the main factor contributing to the increase in impact load resistance. The average pendulum angle values of the six heat-treated compounds were found to have a higher elevation angle than the average values of the original group. There was the least amount of decrease from the average value of the second group, which was 0.93 %. The average toughness values of the six heat-treated groups increased in comparison to the original group's average values, with the second group experiencing the largest percentage increase (11.96%). Based on the difference in coolant temperatures, the group that was cooled in distilled water at zero temperature had the best toughness value.

A Novel Objective Method for Steel Degradation Rate Evaluation.

This article introduces a novel approach for assessing microstructure, particularly its degradation after extended operation. The authors focus on creep processes in power plant components, highlighting the importance of diagnostics in this field. This article emphasizes the value of combining traditional microstructure observation techniques with image analysis. A non-destructive method of evaluating microstructure parameters (matrix replicas) is presented, and its accuracy is evaluated against the conventional destructive method. The assessment utilizes quantitative data derived from classical stereological principles and image analysis. Parameters like mean chord length, relative surface area, mean cross-sectional area, and mean equivalent diameter are compared for replica and metallographic specimens. The results show that the replica method accurately reproduces the microstructure. In their conclusions, the authors highlight the importance of developing visual methods alongside the application of artificial intelligence while indicating the challenges in achieving this goal.

Assessment of the Influence of the Life Cycle of Solar Power Plant Materials and Components on Ecosystem Quality.

Currently, silicon is the most often utilized material for photovoltaic cell manufacturing, as it has the potential to convert solar energy directly into electricity. The silicon used in photovoltaic solutions must be highly pure. Large amounts of power, raw materials, and fossil fuels are consumed in the production process. Post-consumer treatment of polymers, materials, and components also requires energy and matter. These processes have a significant influence on the environment. As a result, the primary purpose of this article is to evaluate the influence of a photovoltaic power plant's material and component life cycle on ecosystem quality. The research focuses on an actual photovoltaic power plant with a capacity of 2 MW located in northern Poland. According to the findings, photovoltaic modules are the part that has the most negative environmental impact, since their manufacturing requires a substantial amount of materials and energy (primarily from conventional sources). Post-consumer management, in the form of recycling after use, would provide major environmental advantages and reduce detrimental environmental consequences throughout the course of the solar power plant's full life cycle.

Analysis of variables in finite element analysis for multi-pass welding in nuclear power plant components, part 2: Focused study on the effect of annealing parameter on hardening behavior

analysis of variables in finite element analysis for multi-pass welding in nuclear power plant components, part 2: Focused study on the effect of annealing parameter on hardening behavior

Electrochemical Study of the Hot Corrosion Behavior of TP347H in Coal Ash

To maximize the effectiveness and efficiency of regular maintenances, it is crucial to predict the lifetime of critical components in coal-fired power plant by understanding the corrosion behavior of alloys in coal ash with varying thickness due to the continuous deposition and under different temperatures. This study explores the hot corrosion behavior of TP347H, which is a material commonly used as superheaters, in coal ash of varying thickness and at different temperatures. Through the use of electrochemical techniques such as open circuit potential (OCP), electrochemical noise, and potentiodynamic polarization (PDP), this study demonstrates a bell-shaped variation in the corrosion rate of TP347H between 650°C and 750°C. Furthermore, it was found that an increase in the thickness of coal ash significantly accelerates the kinetic processes involved in corrosion.

Probabilistic safety assessment of off-site power system under typhoon considering failure correlation between transmission towers

High-intensity typhoons can cause failure to the structures, systems, and components of nuclear power plants (NPPs) and off-site power systems. Instances have occurred where failure of the off-site power system caused by typhoons has affected NPPs. The off-site power system has been in cases where a typhoon failed multiple transmission towers. In Korea, transmission towers have similar design criteria and material properties and experience similar wind characteristics, leading to a correlation in their failure probabilities. Assuming independent or totally dependent failure probabilities among the transmission towers is unrealistic. For a realistic PSA of the off-site power system due to typhoon-induced high winds, it is necessary to consider an appropriate failure correlation. This study performed a PSA of an off-site power system due to typhoon-induced high winds, considering the failure correlation between transmission towers. The failure correlation between transmission towers based on distance was calculated. The wind fragility of the off-site power system was convolved with the typhoon-induced high-wind hazard at the Kori NPP to calculate the probability of the NPP losing its power supply. Thus, applying the failure correlation of typhoon-induced high winds to the PSA of the off-site power system is considered realistic.

Review on the Application of Living PSA in Nuclear Power

With the increasing standards of safety management in nuclear power plants, Living Probabilistic Safety Assessment (Living PSA) technology has begin to play an increasingly important role in their operation. This paper aims to provide an overview of the application and development of Living Probabilistic Safety Assessment (Living PSA) technology in nuclear power plant safety monitoring and risk assessment, examining the key technologies and future challenges. Initially, we summarize the current safety needs in regard to nuclear power, examine the policy on configuration risk management technology for nuclear power plants, and outline its importance and development process in nuclear power plant safety management. Subsequently, we discuss the basic principle of Living PSAs and the working method of risk monitoring based on Living PSAs, including information monitoring data collection, online identification, real-time model updating, and risk calculation. Within the Living PSA framework, model development is not merely about creating a theoretical or static representation; it is a dynamic and ongoing process that involves a deep understanding and precise simulation of the behavior of nuclear power plant systems and components. This represents the main research efforts in Living PSAs at present. Additionally, this paper identifies the key technologies of Living PSAs in an in-depth manner, such as the reliability-model-updating technology and model building in dynamic reliability analyses, including the fault tree model, multi-layer flow model, GO-FLOW model etc. The paper lists the work of some scholars in this area in recent years, which helps readers and researchers to clearly understand the current progress of Living PSA technologies in terms of model establishment and updating. Finally, the paper summarizes the challenges and future development of Living PSA and emphasizes the possible problems in data quality, human factor engineering, and the development of Living PSA technologies in the future. In the future, Living PSAs will provide more solid support for the realization of safer and more economical methods of operating nuclear power plants.

The infrared thermography system on the MAST-U tokamak

Power loading from plasma in the scrape-off layer limits the lifetime of plasma-facing components in tokamak-based power plants. The Mega Ampere Spherical Tokamak Upgrade [W. Morris et al., IEEE Trans. Plasma Sci. 46(5), 1217–1226 (2018)] (MAST-U) features four divertor strike points (SP) owing to its up-down symmetry. This paper introduces the five-camera infrared thermography system, covering all four SPs and their mode of operation on MAST-U. The system employs both medium and long wavelength cameras, offering high frame rates up to 4 kHz and spatial resolutions of down to 3 mm. Postprocessing involves artifact elimination and heat flux calculation using in-house analysis software that incorporates the inverse heat transfer code, THEODOR (THermal Energy Onto DivertOR).

Hydrogen Measurement & Extraction at Nevada Solar One

Hydrogen was measured and extracted from the headspace gas of four expansion vessels that are components of the heat transfer fluid (HTF) subsystem in the Nevada Solar One (NSO) power plant, Boulder City, Nevada. Direct, real-time measurements of hydrogen partial pressures in the headspace gas were accomplished using the recently installed hydrogen mitigation process that was developed jointly by the National Renewable Energy Laboratory (NREL) and Acciona Energy, the owner/operator of NSO. This method combines the two functions of extracting hydrogen from the headspace gas and measuring hydrogen partial pressure in the headspace gas. During 2022 and 2023, we operated the process regularly and made real-time measurements of hydrogen partial pressures. In addition, DLR in Germany measured dissolved hydrogen concentration in the circulating HTF. These two measurements were compared via Henry’s Law and found to be consistent. Measured values also were compared to model results that were generated by the NSO plant model that was written to predict hydrogen levels in the power plant piping and components. The model predicted hourly hydrogen partial pressures in the expansion tanks for two cases - hydrogen extraction off, and hydrogen extraction on. Real-time hydrogen measurements and sampled HTF measurements were compared to hydrogen levels that were predicted for these two cases. We found good agreement between the hydrogen measurements and the modeled hydrogen for the extraction on case. These results indicate that the extraction process is working properly with its expected performance.

Reliability Analysis of Steam Turbine Instrumentation Using the Failure Mode and Effect Analysis (FMEA) Method at PT. PLN Nusantara Power UP Tenayan

PT. PLN Nusantara Power Unit Generation Tenayan is a company operating in the Steam Power Plant sector in Pekanbaru, Indonesia. One of the main components of a steam power plant (PLTU) is a steam turbine. A steam turbine is a machine that functions to convert kinetic energy into electrical current. Operational failures are often caused by less than optimal instrumentation in the steam turbine. This research uses the failure mode and effect analysis (FMEA) method with the aim of identifying the type of failure, the cause of the failure, the effect of the failure, and determining the RPN value. The analysis results from this research show that the turbine instrumentation components still meet performance standards because the risk priority number (RPN) value is less than 200. The conclusion from this research is that errors in steam turbine instrumentation are inaccurate sensor readings, switches cannot deactivate the equipment, and readings control room does not match local readings, the instrumentation component with the highest risk priority number (RPN) is the solenoid valve with a value of 140, and the instrumentation component with the lowest risk priority number (RPN) is the pressure indicator with a value of 30. The component given top priority in action The recommendation is for the solenoid valve component, namely to carry out maintenance every 6 months and add an overspeed protection system

A research and application of a digital failure knowledge model for nuclear power plant

Abstract The accumulation and application of knowledge about equipment component failures in nuclear power plant unit systems is an important way for domestic and foreign nuclear power plants to improve unit availability and economic benefits. Based on the existing equipment component knowledge models in China and the experience of digital transformation, this paper proposes a digital fault knowledge model construction process and method for nuclear power plant components, which is of great significance for standardizing and guiding domestic nuclear power plant knowledge models.

Analysis of variables in finite element analysis for multi-pass welding in nuclear power plant components, part 1: Comprehensive study with experimental validation using scientific weld specimen

The influence of various parameters in welding simulations using finite element analysis (FEA) was investigated in this study. Welding experiments and finite element simulations were conducted to analyze residual stress and post-welding distortion. It was a specially designed V-groove specimen, filled with bead passes using Gas Tungsten Arc Welding (GTAW), that facilitated the measurement of distorted shapes and residual stress. Advanced measurement techniques, including three-dimensional laser scanning and the contour method, were used to capture detailed data on the welded specimen. Three different heat source models (body heat flux, temperature boundary, and Goldak's double-ellipsoidal model) were employed in the simulations, and their effect on residual stress distributions was analyzed. Additionally, the effects of hardening models, bead deposition methods, bead shape modeling, welding sequences, and lumping of weld passes on simulation were systematically analyzed. The findings suggest that a combined approach using different modeling techniques and careful calibration of parameters can enhance the reliability of simulations in predicting weld residual stress and distortions.

Unexpected thermal aging effect on brittle fracture and elemental segregation in modern dissimilar metal weld

A full-scale dissimilar metal weld safe-end mock-up, precisely replicating a critical component of a modern nuclear power plant, was investigated. The brittle fracture behavior, carbide evolution and nanoscale elemental segregation in the heat-affected zone (HAZ) of low alloy steel (LAS) were analyzed under both post-weld heat-treated and thermally-aged conditions (400 °C for 15,000 h, equivalent to 90 years of operation) using analytical electron microscopy and atom probe tomography. The observed increase in grain boundary (GB) decohesion and intergranular cracking on the fracture surface and the decrease of fracture toughness are primarily attributed to P and Mn segregation to GBs and the coarsening of carbides upon long-term thermal aging. The direct observations of significant elemental segregation to GBs and the consequent reduction in fracture toughness in the HAZ are unexpected for modern low-phosphorus LASs, highlighting potential concerns for evaluating the structural integrity of modern nuclear power plants.

Microstructure and properties of underwater in-situ wire-based laser additive manufactured duplex stainless steel

ABSTRACT A novel underwater in-situ wire-based laser additive manufacturing (ULAM) technology is proposed for the in-service repair of underwater components in nuclear power plant. Duplex stainless steel (DSS) obtained in air and underwater environments were analysed using material characterisation and testing methods. The effects of underwater additive environments on the microstructure evolution, mechanical properties and corrosion resistance of the specimens were investigated. The results show that the laser heat input is consumed to balance the heat loss of the water-cooled base material during the underwater laser additive manufacturing process, leading to a reduction in the heat input to the molten pool. Underwater specimen exhibit a two-phase balance, with small ferrite grain boundary angles, resulting in better tensile strength and corrosion resistance. Laser reheat treatment leads to a phase change in microstructure, which can enhance the microhardness and the tensile strength. The ULAM system can meet the requirements of actual engineering for cladding layer.

Experimental and numerical examination of low cycle fatigue behaviour on AISI304L steel

The integrity of the components of nuclear power plants must be guaranteed under operating and emergency conditions. It is necessary to evaluate all possible degradation mechanisms that could impact the structural integrity of nuclear power plant structures such as the pipelines and other components of the cooling systems. Environmental fatigue significantly influences the degradation mechanisms of steel components operating in water, which eventually affects the operational lifetime of the components. Exploring non-codified methods for more precise assessment of fatigue phenomena can pave the way for developing safer nuclear power plants with longer operational lifetimes. This is very important as the global demand for cleaner energy is increasing. This research study deals with a numerical investigation of the low-cycle fatigue behaviour of steel used for those nuclear reactor components where environmental fatigue plays a major role. The numerical simulation methodology is proposed to study the dependence of the kinematic hardening parameter on the strain amplitude to investigate the low-cycle fatigue behaviour of AISI 304L steel for the prediction of the fatigue curves that can be used for the estimation of nuclear power plant safety and its lifetime.The experimental data was used to estimate the parameters required to define the material model for the numerical simulation and to validate the results of the numerical simulation of the low cycle fatigue behaviour. The presented methodology can be used for fully reversed constant-amplitude strain loading low cycle fatigue simulations for various strain ranges to predict the low-cycle fatigue behaviour of steel under repetitive loading.

Design of 600 WP Solar Power Plant for Juice Vendors Through Off-Grid System

Solar power plants (PLTS) generate electricity from the energy of solar photons. Solar cells, or solar cells made of crystalline silicon, are examples of solar panels that generate electricity through the photovoltaic effect. Thus, the construction of solar power plants (PLTS) is one of the right choices to save energy. The purpose of this study is to utilize the energy that is owned and to introduce it to the surrounding community. The community has widely used solar power generation (PLTS) technology, one of the main components of solar power plants is solar photovoltaic technology, which is used to operate juice blenders, cup sealers, and energy-efficient lighting. PLTS functions as an alternative energy source to help juice traders. Based on solar energy for this off-grid system, it has a power capacity of 3 x 200 WP. This monocrystalline solar panel also has a 300 Ah VRLA battery, a 2000 W inverter, and a 50 A solar charger controller (SCC). In addition, the PLTS off-grid system for juice traders has blender equipment, cup sealers, and lighting with an average power rating of 600 Watts. With an efficiency calculation of 80%, this system can be fully used to support business operations. This study is to develop and Design a 600-watt peak Solar Power Plant using an off-grid system for juice vendors that costs Rp. 22,000,000, including all essential components and services needed to ensure that the system can operate properly

Use of mobile metallography to assess the extent of damage to high temperature components in power plants

Abstract Microstructural replicas are used in recurrent testing of hot, pressuriszed components to detect creep damage. The test location must be representative of the damage development and subsequent component failure. Poor preparation leads to the formation of artefacts which are considered in the damage assessment. The assessment is subject to method and operator variability. When assessing the life of components based on microstructure replicas, these must be taken into account and, if necessary, extended stress calculations for the component must be used.

Simulation Study of the Damage Effect of Typical Fragment on UAV Target

Abstract UAV poses a serious threat to ground troops and combat personnel in modern operations, and fighting against UAV is called an important task of air defense operations. Taking DJI UAV as the object, this article researches the typical blasting debris of the prefabricated damage effect of drone target through modeling simulation and simulation calculation, which is focused on damage simulation analysis of the drone battery, power plant, camera and other key components, and studies the damage condition of fragments in different direction and at different speeds, which can improve theoretical basis and reference for fighting against the drone and its swarm.