Plant Operation Research Articles

115 Time-driven Activity-based Costing for ACDF: An Automated and Scalable Solution

INTRODUCTION: Understanding the true (intraoperative) cost to the hospital when neurosurgeons perform anterior cervical discectomy and fusion (ACDF) is critical as we move towards value-based purchasing. METHODS: Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments (business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented. Total intraoperative costs were estimated for all ACDFs from 2017 and 2022. RESULTS: A total of 959 patients underwent anterior cervical fusions between 2017 and 2022 (one-level: n = 400, 41.7%; two-level: n = 407, 42.4%; three-level: n = 139, 14.5%; greater than three-level: n = 13, 1.4%). The most common pre-operative diagnosis was myelopathy (n=586, 61.1%), followed by radiculopathy (n = 256, 26.7%). The average total intraoperative cost per case was $5,970 ± $2,137; $7,542 ± $3,119; $8,958 ± $3,096; and $9,297 ± $2,633 for one-, two-, three-, and greater than three-level fusions, respectively. The major cost contributors were supply costs ($4,745, 66%) and personnel costs ($2,417; 34%). Total intraoperative costs displayed more variation with two-level ACDFs as compared to other fusions. Total supply cost, particularly implant cost ($3,399 ± $2,161), followed by total personnel cost (2,417 ± $917) was responsible for most of the observed total cost variability across all anterior cervical fusions. CONCLUSIONS: TDABC is a feasible and scalable methodology for understanding the true intraoperative costs of ACDF, without having to rely on proprietary third-party software. The most common reason for surgery was myelopathy, followed by radiculopathy. The major cost contributors were supply and personnel costs. Two-level ACDFs appeared to display more total cost variability as compared to other fusions. Implant costs, followed by personnel costs, appeared to be responsible for cost variation across all anterior cervical fusions.

Preface

10th International Symposium on Lead and Zinc ProcessingThe Lead-Zinc conference series, initiated by the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) in 1970, has evolved into a global collaboration of metallurgical societies. This conference series is held every three or five years. It is heartening to acknowledge the significant role played by international organizations including the Minerals, Metals & Materials Society (TMS), Metallurgy & Materials Society of the Canadian Institute of Mining, Metallurgy and Petroleum (MetSoc), the Mining and Materials Processing Institute of Japan (MMIJ), the Society of Metallurgists and Miners (GDMB, Germany), and the Nonferrous Metals Society of China (NFSoc) in fostering knowledge exchange and advancements in lead and zinc industries.The 10th International Symposium on Lead and Zinc Processing (PbZn 2023) was held in Changsha, China, organized by NFSoc and co-sponsored by Central South University (CSU), China ENFI Engineering Corporation (ENFI), and Hunan Science and Technology Association (HSTA). PbZn 2023 had more than 800 attendees, 230 presentations from over 20 countries. This proceedings volume is the result of over a year of collaborative effort, involving authors, editors, and volunteers. Comprising contributions from 20 countries, the volume reflects the global nature of lead and zinc industries, covering business trends, plant operations, fundamental developments, emerging technologies, and environmental considerations. We hope that this compilation will serve as a valuable record of the Lead-Zinc 2023 symposium and become a standard reference for the processing of lead and zinc.We extend our heartfelt gratitude to all the contributors, reviewers, and volunteers who have dedicated their time and expertise to make this proceedings volume a reality.List of International organization, International Organizing Committee, Editorial Committee are available in this Pdf.

HK-SPSA based performance optimization method for steam generator liquid level control

Steam generator level control systems play a crucial role in ensuring safe, economical, and stable operation of nuclear power plants. However, traditional control systems exhibit limited efficiency in commissioning and are susceptible to human error. Additionally, traditional parameter tuning methods are typically experienced-based, cumbersome, and time-consuming, making it challenging to obtain optimal parameters. To address these issues, we propose a hybrid knowledge-guided improved simultaneous perturbation stochastic approximation algorithm (HK-SPSA) to optimize the control parameters of steam generator level control systems. Firstly, the algorithm utilizes iteration point adjacency information to approximate the current optimization process status and guide the adaptive adjustment of the iteration step size. Secondly, it utilizes composite gradient information generated by the estimated historical and current gradients to guide the optimization direction and the tuning of iteration step size. Simulation experiments have shown that HK-SPSA improves optimization performance and reduces the costs of optimization and adjustment compared to traditional methods.

PREVALENCE AND CHARACTERISTICS OF ALLERGIC DISEASES

Allergic diseases(AD) are one of the most urgent problems of modern medicine. The prevalence of bronchial asthma in children and adults in the Bukhara region was studied. The primary incidence of bronchial asthma in the age structure of the population was studied according to the coupons of an outpatient patient (form No. 025-12u) for 2015–2019 in 10 age groups (1–5 years, 5–9 years, 10–14, 19, 20–29, 30–39, 40–49, 50–59, 60 and older) in the city of Bukhara and twelve districts of the Bukhara region.The study of the distribution of indicators of the incidence of bronchial asthma in the Bukhara region revealed that the areas of risk for this pathology are areas with industrial zones: Karakul, Karulbazar and the city of Kagan. The risk groups for the incidence of bronchial asthma are children under 9 years of age and adults aged 60 years and older. The prevalence of bronchial asthma ranges from 5.5 per 1,000 population in relatively clean areas of residence to 33.5 per 1,000 population in industrialized areas.Thus, the study showed that the highest incidence of general morbidity with bronchial asthma in children and adults is observed in the city of Kagan with the operation of an oil extraction plant, in the Karaulbazar district with an oil refinery and in the Karakul district with a Kandim gas processing plant. An increased risk of primary incidence of bronchial asthma exists for children aged 3 to 9 years and for adults 60 years of age and older.

Optimal operation of reverse osmosis desalination process with deep reinforcement learning methods

The reverse osmosis (RO) process is a well-established desalination technology, wherein energy-efficient techniques and advanced process control methods significantly reduce production costs. This study proposes an optimal real-time management method to minimize the total daily operation cost of an RO desalination plant, integrating a storage tank system to meet varying daily freshwater demand. Utilizing the dynamic model of the RO process, a cascade structure with two reinforcement learning (RL) agents, namely the deep deterministic policy gradient (DDPG) and deep Q-Network (DQN), is developed to optimize the operation of the RO plant. The DDPG agent, manipulating the high-pressure pump, controls the permeate flow rate to track a reference setpoint value. Simultaneously, the DQN agent selects the optimal setpoint value and communicates it to the DDPG controller to minimize the plant’s operation cost. Monitoring storage tanks, permeate flow rates, and water demand enables the DQN agent to determine the required amount of permeate water, optimizing water quality and energy consumption. Additionally, the DQN agent monitors the storage tank’s water level to prevent overflow or underflow of permeate water. Simulation results demonstrate the effectiveness and practicality of the designed RL agents.

Integrated application of synergetic approach for enhancing intelligent steam generator control systems

This article focuses on the integrated application of the synergetic approach to enhance the quality of intelligent steam generator control systems.By combining various techniques such as model-based control, adaptive control, and artificial intelligence, an efficient and flexible control system can be developed. Model-based control utilizes mathematical models of steam generators to formulate control algorithms and predict system behavior. Adaptive control enables the system to adapt to changing conditions by adjusting control parameters based on real-time measurements. Artificial intelligence techniques, including neural networks and genetic algorithms, facilitate learning, optimization, and data-driven decision-making processes. The objectives of this research are to investigate the benefits of the synergetic approach in steam generator control, including improved steam generation efficiency, optimized energy consumption, enhanced system stability and reliability, and adaptability to varying operating conditions and disturbances. The findings and conclusions of this study are expected to provide valuable insights for engineers, researchers, and professionals involved in the design and implementation of intelligent steam generator control systems. By integrating the synergetic approach, substantial enhancements in control quality can be achieved, leading to optimal operation and maximum efficiency of power plants.

An efficient authentication protocol with privacy-preserving for virtual power plant

As an important manifestation of the current development and transformation of the world’s power and energy industries, the virtual power plant is an important foundation for optimizing the layout of energy resources. However, since there are many open channels in the virtual power plant, adversaries can implement eavesdropping, replay, impersonation, forgery, and other attacks to access the virtual power plant, and even publish false data in the virtual power plant to disrupt the operation of the virtual power plant. In addition, it is easy for an adversary to deduce key information such as the layout of virtual power plant equipment through the identity of the device. In this context, to ensure the security and privacy of devices when accessing the platform, in this paper, we propose an efficient authentication protocol based on the elliptic curve cryptography and zero-knowledge proof, which requires only two information exchanges. Security analysis shows that the proposed protocol can meet security features such as mutual authentication, key agreement, perfect forward secrecy, and device anonymity. Performance analysis indicates that the proposed protocol achieves a reasonable balance between computational and signaling overhead, and it is more suitable for achieving efficient device authentication and privacy protection in virtual power plants.

Insightful Analysis and Prediction of SCOD Component Variation in Low-Carbon/Nitrogen-Ratio Domestic Wastewater via Machine Learning

The rapid identification of the amount and characteristics of chemical oxygen demand (COD) in influent water is critical to the operation of wastewater treatment plants (WWTPs), especially for WWTPs in the face of influent water with a low carbon/nitrogen (C/N) ratio. Given that, this study carried out batch kinetic experiments for soluble chemical oxygen demand (SCOD) and nitrogen degradation for three WWTPs and established machine learning (ML) models for the accurate prediction of the variation in SCOD. The results indicate that four different kinds of components were identified via parallel factor (PARAFAC) analysis. C1 (Ex/Em = 235 nm and 275/348 nm, tryptophan-like substances/soluble microbial by-products) contributes to the majority of internal carbon sources for endogenous denitrification, whereas C4 (230 nm and 275/350 nm, tyrosine-like substances) is crucial for readily biodegradable SCOD composition according to the machine learning (ML) models. Furthermore, the gradient boosting decision tree (GBDT) algorithm achieved higher interpretability and generalizability in describing the relationship between SCOD and carbon source components, with an R2 reaching 0.772. A Shapley additive explanations (SHAP) analysis of GBDT models further validated the above result. Undoubtedly, this study provided novel insights into utilizing ML models to predict SCOD through the measurements of the excitation–emission matrix (EEM) in specific Ex and Em positions. The results could help us to identify the degradation and transformation relationship between different kinds of carbon sources and nitrogen species in the wastewater treatment process, and thus provide a novel guidance for the optimized operation of WWTPs.

Pyrolysis process control: temperature control design and application for optimum process operation

Fast pyrolysis in auger reactor gains attention for efficient bio-oil production. Due to the quick nature of the process, precise temperature control using the proportional-integral-derivative (PID) algorithm is paramount. This study harnesses various PID tuning approaches through modelling and experimental validation to optimize continuous and precise pyrolysis temperature. System identification was done to investigate the process dynamic with fit accuracy above 93% and design a suitable PID control. Comparison with the experiment data shows a favorable result with rise time and settling time match above 75%. Ziegler-Nichols (ZN) and Cohen-Coon (CC) tuning methods were implemented in the system with undistinguished results, yielding steady-state error (SSE) below 1% and settling time around 4,300 to 4,800 seconds. The heuristic fine-tuning method improved the rise time and settling time by stabilizing before 3,600 seconds. Furthermore, the robustness of PID controllers was verified with a disturbance rejection test, keeping the SSE deviation inside the boundary of 2%. Finally, the setup could support maximum pyrolytic oil production by 69.6% at 500 °C. The result implies that the PID controller could provide a stable and rugged response to support a productive and sustainable pyrolysis plant operation.

Prolongation of Safe Operation of the K-1000-60/3000 Turbine Power Unit after Damage to the HPC Rotor

Currently, when large-scale military actions are taking place on the territory of Ukraine, the inclusion of the domestic energy system in the European one is a reliable component of providing electricity to the country's energy market. However, according to experts, uninterrupted and safe operation of nuclear power plants is still considered a prerequisite for the stable operation of the energy sector of Ukraine. The purpose of the paper is to assess the damageability and individual resource of the rotor of high-pressure cylinder (HPC) of the K-1000-60/3000 turbine power unit of the LMZ after damage to the blades in order to prolong the operation of the power unit in the conditions of a stressed state of the power system. One of the most effective ways to partially solve the problem of replacement of generating capacities is to extend the operating periods of NPP power units after the end of the project operating period, provided that nuclear and radiation safety standards are met. The review of the previously established service life of the energy equipment of NPP power units involves the assessment of the residual resource of the energy equipment in accordance with the regulatory documents. After the accidental damage of the blades of the last stage of the HPC rotor of the K-1000-60/3000 turbine power unit of the LMZ, there was a need to study the cyclic and static damage, the individual residual resource of the HPC rotor. In the process of achieving the goal, studies were carried out for three design options: the original option (five stages of the HPC rotor), the option without the blades of the last stage and the option without the fifth stage (with four first stages). The calculation of the resource indicators of the rotor in the execution of the HPC without blades of the 5th stage shows that the static damage accumulated in the main metal is 52%, the cyclic damage is 5% when applying the standard strength reserves for the number of cycles and for deformations at the level of nN=10 and nε=1.5 according to the recommendations of SOU-N MEV 40.1-21677681-52:2011. Thus, the total damage to the base metal is 57%, which sets the residual resource of the HPC rotor at the level of 88.4 thousand hours. The calculation of the resource indicators of the rotor in the execution of the HPC without entire 5th stage shows that the static damage accumulated in the base metal is 52%, the cyclic damage is 6% when applying the standard strength reserves for the number of cycles and deformations at the above-mentioned level. The total damage to the base metal is 58%, which determines the residual resource of the HPC rotor at the level of 85.6 thousand hours.

Increase of the Efficiency of Heat Supply Units of the CHP Plants Due to the Choice of Rational Heat Release Modes

The possibilities of increasing the efficiency of heat supply turbines of CHPPs due to the choice of rational modes of operation of network water heaters are analyzed. With the help of a software and computing complex developed at the Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine and adapted by the authors to the operating conditions of CHPP generating equipment with one or two network heaters, a set of calculation studies of various ways of connecting them depending on the outdoor air temperature is conducted in the paper. Areas of positive effect associated with increase in the electric power of the power plant have been established. The calculation study was carried out at typical power plant water consumption from 1000 t/h to 4500 t/h, in the range of changes in the outdoor air temperature from -11 ºС to 10 ºС (heating season) and more than 10 ºС (hot water supply). The load change of the power unit was carried out due to the consumption of fresh steam at a constant pressure and temperature at the turbine inlet. As shown by the results of the operation of the T-100/120-130 heat supply turbine in operating conditions with one or two heat supply steam selections, in the area of positive outdoor air temperatures above 2 ºС, it is advisable to use one lower selection (with the upper one turned off) for all network water consumption. At the same time, additional electric power in the area of outdoor air temperatures above 6ºС can be from 0.25 MW to 2.15 MW. However, when the outdoor air temperature is less than 2 ºС, work with one lower heating selection becomes irrational. From the point of view of choosing rational modes of operation of turbine plants, the most important are the results of determining the optimal distribution of heat load between network heaters. The gain in electrical power of the turbine can be up to 2.46 MW in the nominal mode of operation with two heaters, and up to 7.84 MW in comparison with the use of single-stage heating. The nature of the influence of the distribution of the heat load indicates that during deprivation from the instructional uniform distribution of the heat load between network heaters, it is possible to obtain additional electricity.

Modeling and evaluating mill plant production using AggFlow software: Case study in the South of Jordan

Purpose.This paper aims to investigate the process of modeling and simulating the mill plant operations with a specific emphasis on the use of AggFlow software. The main purpose is to highlight the importance of modern approaches in to mill plant operation, with a focus on the crucial role of simulation in improving production processes, reducing inefficiencies and optimizing resource use. Methods. The AggFlow software is used to model current operations at a mill plant in Jordan with a specific emphasis on the limestone production in different size fractions. The accuracy of the simulation is verified by carefully comparing it with actual operational data, confirming the AggFlow effectiveness in predictive modeling to enhance mill plant performance. Findings. This study has systematically increased the production rates of mill plant products through thorough analysis while ensuring that the supplying conditions remain consistent. The aim was to increase production efficiency while guaran-teeing the marketability of the finished products. The findings provided useful insights into effective operational modifications and strategies for enhancing production rates while maintaining product quality. Originality. This research provides novel insights by integrating actual mill plant operations with sophisticated simulation utilizing AggFlow software. The study confirms the reliability of AggFlow as a tool for predicting models and offers new insights into enhancing production efficiency in mill plant environments. Practical implications.The research results are directly applicable to mill plant operators, providing a realistic method for improving operational efficiency through the use of AggFlow simulation. The research provides practical methods that can be implemented to optimize production rates and maintain consistent product quality in mill plant operations.

Multi-Objective Optimization Based on Simulation Integrated Pareto Analysis to Achieve Low-Carbon and Economical Operation of a Wastewater Treatment Plant

It is essential to reduce carbon emissions in wastewater treatment plants (WWTPs) to achieve carbon neutrality in society. However, current optimization of WWTPs prioritizes the operation cost index (OCI) and effluent quality index (EQI) over greenhouse gas (GHG) emissions. This study aims to conduct a multi-objective optimization of a WWTP, considering GHG emissions, EQI, and OCI. The anaerobic-anoxic-oxic integrated membrane bioreactor (AAO-MBR) process in an actual WWTP was selected as a typical case, tens of thousands of scenarios with combinations of six operational parameters (dissolved oxygen (DO), external carbon resource (ECR), poly aluminum chloride (PAC), internal reflux ratio (IRR), external reflux ratio (ERR), and sludge discharge (SD)) were simulated by GPS-X software (Hydromantics 8.0.1). It was shown that ECR has the greatest impact on optimization objectives. In the optimal scenario, the main parameters of ATDO, MTDO, IRR, and ERR were 0.1 mg/L, 4 mg/L, 50%, and 100%, respectively. The EQI, OCI, and GHG of the best scenario were 0.046 kg/m3, 0.27 ¥/m3, and 0.51 kgCO2/m3, which were 2.1%, 72.2%, and 34.6% better than the current situation of the case WWTP, respectively. This study provides an effective method for realizing low-carbon and economical operation of WWTPs.

Development of pre‐startup safety review implementation tool for safe operation in process plant

AbstractA pre‐startup safety review (PSSR) is a formal review of a chemical manufacturing process to verify that critical areas of the affected process have been assessed and addressed before using the process. It can be a new process or after modification to an existing process or operating conditions. There is concern about full implementation compliance, including designing the PSSR program, preparing the process to perform PSSR, following PSSR action items, and approving the PSSR report. This study aims to develop a PSSR Implementation Tool (PSSR‐IT) via the Microsoft Excel platform. At the end of the self‐assessment process, the end users were provided with the value of the percentage of compliance with PSSR requirements and a thorough review process prior to the start‐up activities. A safety experts’ content validation index (CVI) was performed to ensure the tool's content was valid and sufficient for the PSSR process, followed by a case study. Feedback from process safety engineers and PSSR leaders as end users has been collected through the System Usability Scale (SUS). A total of 227 questions have been listed under 10 disciplines, including general info, operation, engineering, operational, process safety, health safety and environment (HSE), action log, final walk down, and approval that cover all essential aspects of review process prior to the start‐up activities with CVI value of 0.98, k = 0.67. SUS findings demonstrated that all industrial experts and end users believe the tool is suitable and reliable, with a score >85%. Utilizing the PSSR tool will help the industries promote and improve the process safety program at the workplace.

Valorization of Wood Residues from Vegetation Suppression during Wind Energy Plant Implementation and Its Potential for Renewable Phenolic Compounds through Flash Pyrolysis: A Case Study in Northeast Brazil’s Semi-Arid Region

In the past few years, wind power has become a viable alternative in Brazil to diversify the energy mix and mitigate pollutant emissions from fossil fuels. Significant wind energy generation potential is inherent in the Brazilian Northeast state of Rio Grande do Norte, due to prevailing strong winds along the coastline and elevated regions. However, clean and renewable wind energy may lead to potential biodiversity impacts, including the removal of native vegetation during plant construction and operation. This case study explores the flash pyrolysis-based valorization of three commonly suppressed species, namely Cenostigma pyramidale (CP), Commiphora leptophloeos (CL), and Aspidosperma pyrifolium (AP), in a wind farm situated within the Mato Grande region of Rio Grande do Norte State. The study centers on determining their bioenergy-related properties and assessing their potential for producing phenolic-rich bio-oil. The investigation of three wood residues as potential sources of high-value chemicals, specifically phenolic compounds, was conducted using a micro-furnace type temperature programmable pyrolyzer combined with gas chromatography/mass spectrometry (Py–GC/MS setup). The range of higher heating values observed for three wood residues was 17.5–18.4 MJ kg−1, with the highest value attributed to AP wood residue. The bulk density ranged from 126.5 to 268.7 kg m−3, while ash content, volatile matter content, fixed carbon content, and lignin content were within the respective ranges of 0.8–2.9 wt.%, 78.5–89.6 wt.%, 2.6–9.5 wt.%, and 19.1–30.6 wt.%. Although the energy-related properties signifying the potential value of three wood residues as energy resources are evident, their applicability in the bioenergy sector can be expanded via pelleting or briquetting. Yields of phenolic compounds exceeding 40% from the volatile pyrolysis products of CL and AP wood residues at 500 °C make them favorable for phenolic-rich bio-oil production. The findings of this study endorse the utilization of wood residues resulting from vegetation suppression during the installation of wind energy plants as potential feedstocks for producing bioenergy and sustainable phenolic compounds. This presents a solution for addressing a regional environmental concern following the principles of green chemistry.

Initial carbon capture pilot study in Solvay soda ash process

Aqueous ammonia is an alternative solvent for CO2 capture that has many advantages. In recent years, researchers have investigated ammonia as a promising solvent for CO2 capture from various gases. A significant emitter of carbon dioxide from the chemical sector is the soda ash industry. Since ammonia is an auxiliary substrate in soda production, it can easily be used to capture CO2 from tail gas streams. After CO2 absorption, process liquids can be returned to the production process, helping to reduce the use of raw materials.The main source of CO2 emissions to the atmosphere in the Solvay Process is the post-carbonation gas from the carbonating tower. It has been demonstrated that this process can be intensified and the use of calcium carbonate in the form of limestone is reduced by returning the carbon dioxide to the process. Stoichiometrically, one kg of avoided CO2 saves approximately 2.27 kg of limestone. This paper presents the initial results and lessons learned from the operation of the pilot plant for CO2 capture from tail gas streams of the Solvay Process. The process has been tested and implemented in a pilot plant with a gas flow rate of up to 4000 m3n/h. The influence of various process parameters has been investigated.

Boiler Combustion Adjustment and Economic Operation Affect Boiler Combustion Factors

Thermal power generation, as the most stable power output in China, plays a rather crucial role in the construction of China's economy. The most important power generation equipment of thermal power plant is the boiler, only good control of the boiler operation of the power plant, in order to better enable it to participate in the power generation work. Combined with the Linfen Thermal Power Co., Ltd. related boiler unit operation status, combustion adjustment optimisation content analysis, give the corresponding recommendations, so as to make the boiler operation more stable, safe, environmentally friendly, power plant power generation to make the corresponding contribution.

Methods of determining internal damage in power transformers

Due to the variety of defects that arise in electrical machines, it is necessary to use more effective methods for monitoring their condition. All over the world research and development of new means and methods for monitoring powerful electrical machines during their operation is underway. Some examples of recent advances are vibration diagnostic methods for assessing the compaction of components inside a transformer, acoustic and electrical systems for monitoring partial discharges, data processing using digital methods, and new sensors for continuous monitoring of gases and moisture in oil, as well as hot spot temperatures. Additionally, thermal imaging testing of power equipment is also an important tool to ensure reliable operation. It is believed that the most effective method is gas chromatographic oil analysis, which can identify most defects in oil-filled equipment. During the operation of powerful electrical machines, the use of existing non-destructive testing methods does not allow a complete assessment of the condition of the main parts of the equipment, as an analysis of damage locations shows, 25% are damage to the core and windings. Effective monitoring of the condition and determination of the performance of transformers is of particular importance, since they are key elements in the operation of nuclear power plants. The paper considers the possibility of using the eddy current testing method; determining a defect in magnetic core steel is based on fixing the unevenness of the magnetic field on the horizontal or vertical planes of a yoke or rod consisting of electrical steel plates. Monitoring and evaluating the functioning of existing equipment, detecting deficiencies in the early stages of their development, when repair costs are still minimal, and preventing emergency failures become a priority. In accordance with the growth rate of detected deficiencies, monitoring is carried out from time to time or continuously, the maximum number of monitored characteristics is achieved when the transformer is fully tested to determine its functionality.

Evaporator with horizontal water plane stabilization

Evaporation plays an important role in maintaining water balance and managing water resources in reservoirs. This problem is relevant in hot regions with a lack of fresh water. In addition, reliable operation of evaporators plays an important role in preventing overheating and ensuring safe cooling of reactors which is critical to maintaining nuclear safety. The complete control and accurate measurement of the evaporation process provided by the developed device enables efficient water management ensuring the stability of nuclear power plants and minimising environmental risks. Evaporators are used to control the evaporation process in reservoirs. Based on the analysis of existing evaporators and their shortcomings, an evaporator with horizontal plane stabilization in the pan is developed. Due to this function the developed device allows to control the evaporation process with higher accuracy by reducing fluctuations in the water level in the evaporator. The developed device contains an autonomous power supply that uses energy-saving technology based on a solar battery which ensures operation without additional sources. The use of such a power supply increases the evaporator reliability. One of the important advantages of this device is the use of a cellular-based information transmission channel to the control center which allows to transmit the results of evaporation quickly monitoring and make water management decisions accordingly. In addition, the use of a GPS navigation system allows to set or determine the coordinates of the evaporator installation in the reservoir accurately. The developed device can be included in an intelligent energy resource management system; its use will significantly improve the safety and sustainability of nuclear power plants by improving evaporation process control. It will also optimize the nuclear power plants operation, promote efficient management of water resources and ensure safety in the nuclear energy field.

Safety evaluation of Multiple Steam Generator Tube rupture accident using the best estimate plus uncertainty approach

Following the disaster in Fukushima Nuclear Power Plant (NPP) in 2011, the awareness of securing the safety of NPP under extreme events has been raised. For this purpose, the concept of Design Extension Conditions (DECs) was introduced, to enhance the plant’s capability to withstand events that are more severe than Design Basis Accidents (DBA), such as Multiple Steam Generator Tube Rupture (MSGTR) accident, given its rapid progression and significant potential for large release of radioactive materials to the environment. It is worth noting that MSGTR has never occurred during the commercial operation of nuclear power plant, therefore the knowledge of consequences of the event and potential mitigation strategy is limited. In this study, a postulated MSGTR (simultaneous rupture of 5 U-tubes in a single SG) accident is analysed using the best-estimate thermal hydraulics code RELAP5/SCDAPSIM/MOD3.4. The main focus of this work is evaluation of appropriate operator mitigation actions under various inherent uncertainties. To this end, the best estimate plus uncertainty (BEPU) approach is adopted, whereby RELAP5/SCDAPSIM/MOD3.4 was coupled to the statistical analysis software, DAKOTA, to conduct the uncertainty quantification (UQ). Using BEPU analysis, an ensemble of system responses under various epistemic and aleatory uncertainties is obtained and used to validate the efficacy of operator actions in bringing the plant to a safe shutdown condition.