Capacity Of Nuclear Power Plants Research Articles

Multihazard capacity optimization of an NPP using a multi-objective genetic algorithm and sampling-based PSA

After the Tohoku earthquake and tsunami (Japan, 2011), regulatory efforts to mitigate external hazards have increased both the safety requirements and the total capital cost of nuclear power plants (NPPs). In these circumstances, identifying not only disaster robustness but also cost-effective capacity setting of NPPs has become one of the most important tasks for the nuclear power industry. A few studies have been performed to relocate the seismic capacity of NPPs, yet the effects of multiple hazards have not been accounted for in NPP capacity optimization. The major challenges in extending this problem to the multihazard dimension are (1) the high computational costs for both multihazard risk quantification and system-level optimization and (2) the lack of capital cost databases of NPPs. To resolve these issues, this paper proposes an effective method that identifies the optimal multihazard capacity of NPPs using a multi-objective genetic algorithm and the two-stage direct quantification of fault trees using Monte Carlo simulation method, called the two-stage DQFM. Also, a capacity-based indirect capital cost measure is proposed. Such a proposed method enables NPP to achieve safety and cost-effectiveness against multi-hazard simultaneously within the computationally efficient platform. The proposed multihazard capacity optimization framework is demonstrated and tested with an earthquake–tsunami example.

Перспективні напрямки проведення модернізації засобів управління режимом навантаження в Об’єднаній енергосистемі України

Considered a promising possibility in the system of dispatching control of the load mode of the United energy system of Ukraine to ensure the processes of regulating the generating capacities of NPP stations. The new direction of construction of control systems using the United energy system of Ukraine mode will make it possible to abandon too expensive means of maneuverable generation, such as the construction of reserve stations with highly maneuverable TPPs that have high-speed start-up characteristics, as well as frequency control support systems using powerful storage batteries. Instead, it is proposed to use powerful automatically controlled electric boilers, previously included in the means of regulating the load regime of the combined energy system. This will contribute to the further development of the generating capacity of nuclear power plants, wind power plants, and thermal power plants, as well as to the resolution of issues related to ensuring the stability and sustainability of the combined power system. Keywords: Unified power system, powerful electric boilers, automated dispatch control system, daily electrical load schedule, main power transmission lines.

The development options of nuclear power under carbon dioxide emissions constraints

The aim of the work is forecasting the development of nuclear power in Russia and the world for the period up to 2050 under various scenarios of constraints on carbon dioxide emissions. A brief comparative analysis of the main characteristics of the forecasts of the International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA) has been carried out. Additionally, calculations were performed using the mathematical models of the world energy system GEM and GEM-Dyn developed at the ISEM SB RAS. The optimal ratio of nuclear and non-nuclear energy sources has been determined. It is shown that nuclear power, including nuclear power plants operating on a closed fuel cycle, along with renewable energy sources, is an effective technology that can solve the problem of reducing carbon dioxide emissions. Calculations have shown that in the sustainable development scenario, the capacity of nuclear power plants in Russia in the period from 2020 to 2050 can increase by 2.7 times, and their share in electricity generation can reach 21–25% in 2030 and 26–35% in 2050. The average annual growth rate (for 30 years) of the installed capacity of nuclear power plants in Russia in the sustainable development scenario is 3.1% compared to 2.7% for the world as a whole. In the GEM and GEM-Dyn calculations performed by the authors, the scale of nuclear energy use turned out to be about 30% higher than in the scenarios of the International Energy Agency due to more conservative estimates of the opportunities for improving the performance of renewable energy sources and taking into account the need to back-up their capacity.

State or market: Investments in new nuclear power plants in France and their domestic and cross-border effects

France wants to become carbon-neutral by 2050. Renewable energies and nuclear power are expected to make the main contribution to this goal. However, the average age of nuclear power plants is approaching 37 years of operation in 2022, which is likely to lead to increased outages and expensive maintenance. In addition, newer nuclear power plants are flexible to operate and thus compatible with high volatile feed-in from renewables. Nevertheless, it is controversially discussed whether nuclear power plants can still be operated competitively and whether new investments will be made in this technology. Using an agent-based simulation model of the European electricity market, the market impacts of possible nuclear investments are investigated based on two scenarios: a scenario with state-based investments and a scenario with market-based investments. The results of this investigation show that under our assumptions, even with state-based investments, carbon neutrality would not be achieved with the estimated nuclear power plant capacity. Under purely market-based assumptions, large amounts of gas-fired power plants would be installed, which would lead to an increase in France’s carbon emissions. State-based investments in nuclear power plants, however, would have a dampening effect on neighboring spot market prices of up to 4.5% on average.

УКРАЇНА ЯК ГЛОБАЛЬНИЙ ГРАВЕЦЬ У СВІТОВІЙ ЕКОНОМІЦІ В ТРЕТЬОМУ ДЕСЯТИЛІТТІ ХХІ СТОЛІТТЯ

The purpose of the study is to identify the prospects for the development of the national economy and the transformation of the infrastructure of Ukraine in the post-war reconstruction based on the study of the resource base, intellectual potential and the vision of other countries' development of our country. The research methodology is a critical analysis of the state and development prospects of elements of the socio-economic system using rating, comparative analysis and logical judgments. Based on the study of scientific articles, it has been proven that Ukraine has a high resource potential. Also, the country's economic system significantly affects the stock market, energy, food and fertilizer markets. We occupy the first place in Europe in terms of proven reserves of uranium ores and the first position in terms of arable land, the first place in the world in the export of sunflower and sunflower oil. We rank second in the world in terms of reserves of titanium, iron, and mercury ores, as well as in the installed capacity of nuclear power plants. The country ranks third in Europe in terms of shale gas reserves and the area of black soil. The results of modelling according to the National Institute Global Econometric Model (NiGEM) are given: a decrease in the level of world GDP by 1.0% and an increase in global inflation to 3.0% in 2022. The main negative consequences of the Russian-Ukrainian war are highlighted. The main economic factors of influence include the opportunity cost of military investments; humanitarian losses of the financial system; the burden of post-war reconstruction. The work proves that the resource economy can provide insignificant revenues to the budget. It is emphasized the need to start the production of goods and the provision of services in the field of high technologies, in particular, based on Industry 4.0. Based on the analysis of the Human Capital Index, the need to develop the intellectual potential of Ukraine is substantiated. The main points for increasing the Investment Attractiveness Index are given. The practical significance of the results lies in the possibility of developing the national economy of Ukraine based on the existing resource base, taking into account the intellectual potential to raise the subjectivity of the country to the level of a global player and successful integration into the cohort of countries with developed socio-economic systems.

ANALYSIS OF MODELS OF AN AUTOMATIC POWER CONTROL SYSTEM FOR A PRESSURIZED WATER REACTOR IN DYNAMIC MODE WITH A CHANGE IN THE STATIC CONTROL PROGRAM

The process of decarbonization of the industry was intensified by the decision to include nuclear energy in the EU Green Taxonomy. The increase in the capacity of nuclear power plants and the attractiveness of this industry for a long time causes interest in the use of nuclear power plants for electricity dispatching. Thus, the development of an automatic control system for changing the power of nuclear power plants in dynamic modes becomes relevant. The energy release along the height of the reactor core under the action of xenon fluctuations is one of the problems in ensuring the safe operation and stability of the NPP power unit when the power level changes. Violation of the energy release safety criteria occurs when non-stationary transient xenon processes with positive feedback occur in the core. Within the framework of the automatic control theory, the modeling of the system and the control object is compiled on the basis of the use of physical and mathematical models. Transfer functions, structure and parameters of the control system are determined. As an alternative, it is proposed to use an approximation model of the process in the core. The model is presented on the basis of transformations in such a way that the results of the calculation on a certain interval coincide or are close to the results of the calculation when using the analytical model. Such a model can approximate a process that depends on two parameters: time and degree of load change. The results of changing the regulation of technological parameters by the automated power control system of nuclear power unit in dynamic mode, the model of which is based on an approximation or physical and mathematical model, were analyzed. The results of changing the parameters are obtained by comparing the results during the transition of control from one static program to another. Switching between static control programs was studied for such process parameters as coolant temperature at the entrance to the reactor core, average coolant temperature and steam pressure in the secondary circuit. The studies were carried out under the condition that the reactor power was reduced to 80 % during the operation of one control program and increased to 100% of the power when another static program was used in reverse.

Seismic capacity re-evaluation of the 480V motor control center of South Korea NPPs using earthquake experience and experiment data

The recent seismic events that occurred in South Korea have increased the interest in the re-evaluation of the seismic capacity of nuclear power plant (NPP) equipment, which is often conservatively estimated. To date, various approaches—including the Bayesian method proposed by the United States (US) Electric Power Research Institute —have been developed to quantify the seismic capacity of NPP equipment. Among these, the Bayesian approach has advantages in accounting for both prior knowledge and new information to update the probabilistic distribution of seismic capacity. However, data availability and region-specific issues exist in applying this Bayesian approach to Korean NPP equipment. Therefore, this paper proposes to construct an earthquake experience database by combining available earthquake records at Korean NPP sites and the general location of equipment within NPPs. Also, for the better representation of the seismic demand of Korean earthquake datasets, which have distinct seismic characteristics from those of the US at a high-frequency range, a broadband frequency range optimization is suggested. The proposed data construction and seismic demand optimization method for seismic capacity re-evaluation are demonstrated and tested on a 480 V motor control center of a South Korea NPP.

Improvement of the high pressure cylinder of the turbine K-1000-60/1500-2 of the Balakovo NPP 4-th block

ncreasing the capacity of nuclear power plants is a global trend and is widely implemented in Europe and the United States. Usually, work to increase the capacity of nuclear power units is carried out during planned reconstructions. Features of such reconstruction are partial replacement of the equipment that in comparison with full gives considerable economy of resources. The use of this approach allows partially replacing the elements of the flow part, which in turn is performed in order to provide the necessary flow parameters in the flow part of the turbomachine, and also allows reusing unmodified structural elements. This article summarizes the experience of JSC "Turboatom" in improving the high pressure cylinder, as well as the design features of the project to modernize the turbine K-1000-60 / 1500-2 unit 4 Balakovo NPP produced by JSC "Turboatom". As part of the modernization project, JSC "Turboatom" performed a set of thermal and strength calculations of the HPC of the turbine K-1000-60 / 1500-2, taking into account the increase in thermal capacity of the reactor to 3210 MW using existing parts and assemblies. The design and circuit decisions in the project of modernization of the turbine K-1000-60 / 1500-2 4-th block Balakovo NPP and a high degree of unification of its elements, worked out and mastered in the manufacture and operation of stations, improve the quality of its maintenance and repairs, allow us to believe that this turbine will have high technical and economic performance, as well as ensure its high competitiveness on the outside market. The advanced flowing part of HPC is equipped with the developed system of removal of moisture. Moisture removal from the intercrown gaps is carried out by a system of drainage holes in the diaphragm visors. Moisture from the interstage gaps is discharged into the moisture removal chamber behind the blades. The efficiency of moisture removal behind the blades is provided by a conical meridional circumference of the blades and moisture-collecting grooves on the bandages of the blades. The estimated value of the increase in electric power of the turbine K-1000-60 / 1500-2 4-th block Balakovo NPP with increasing the thermal capacity of the reactor to 3210 MW is 52.56 MW.

Analysis of hydrogen risk and its mitigation systems in CPR1000 during shutdown conditions

Analysis of hydrogen risk and the effectiveness of hydrogen mitigation systems during shutdown conditions is of great importance to support the development of the low power and shutdown (LPSD) probabilistic safety assessment (PSA) model and improve the capacity of nuclear power plants (NPPs) to reduce the hydrogen risk during shutdown conditions. This study deals with the identification of hydrogen risk and optimization of current hydrogen mitigation systems in the CPR1000 nuclear power plant during shutdown conditions before vessel head open. A detailed MELCOR input is developed, which includes detailed containment nodalization, accurate configuration of the passive autocatalytic recombiner (PAR) systems, and realistic boundary conditions based on design data and technical specifications. Three cases that represent different coolant inventory and specific hydrogen release paths are selected, and the accident progression and hydrogen risk are analyzed subsequently. The analysis indicates that the hydrogen risk is still an important issue during shutdown conditions, although the accident progression is relatively slow. PAR systems with the current configuration are added to the plant model to verify the effectiveness of the hydrogen mitigation system in the CPR1000 during shutdown conditions. The results indicate that the current configuration of PAR systems is still effective in mitigating the hydrogen risk following accidents during cold shutdown POS with PZR manhole close but is insufficient to mitigate the hydrogen risk during an accident with PZR manhole open. Therefore, two strategies to improve the hydrogen mitigation systems are proposed, and their effectiveness are compared. It is concluded that at least 12 additional PAR systems or an ignitor should be added to the PZR room to avoid severe hydrogen risk during shutdown conditions, and the additional PAR systems is the prior consideration.

Optimization of hydrogen mitigation systems in CPR1000 during a refueling outage

This study deals with the identification of hydrogen risk and optimization of current hydrogen mitigation systems in the CPR1000 nuclear power plant (NPP) during a refueling outage. A detailed MELCOR input is developed, which includes detailed containment nodalization, accurate configuration of the passive autocatalytic recombiner (PAR) systems, and realistic boundary conditions based on design data and technical specifications. Two cases that represent different plant operation states (POS) and specific hydrogen release paths are selected, and the accident progression and hydrogen risk are analyzed subsequently. The analysis indicates that the hydrogen risk is still of great importance during a refueling outage, although the accident progression is relatively slow. PAR systems with the current configuration are added to the plant model to verify the effectiveness of the hydrogen mitigation system in the CPR1000 during a refueling outage. The results indicate that the current configuration of PAR systems is still effective in mitigating the hydrogen risk during an accident in POS E but is insufficient in mitigating the hydrogen risk during an accident in POS H. Therefore, two strategies to improve the hydrogen mitigation systems are proposed, and their effectiveness is compared. It is concluded that mobile ignitors should be employed in the refueling pool region to avoid severe hydrogen risk during a refueling outage. The results of this study can support the development of the low power and shutdown (LPSD) probabilistic safety assessment (PSA) model and improve the capacity of NPPs to reduce the hydrogen risk during a refueling outage.

Rebar section loss and carbon fiber reinforced plastic reinforcement effects on nonlinear behavior and ultimate load of cooling towers

The present paper quantifies the adverse effects that can generate rebar section loss, induced by corrosion, especially on the bearing capacity of nuclear power plant cooling towers under extreme wind conditions. Numerical simulations, taking into account, appearance of concrete cracks and their evolution via an appropriate material concrete law and rebar’s yielding, are conducted. Different levels of corrosion are considered which are approximated by rebar section loss. Finally, to restore the integrity of these structures, composite material such as a carbon fiber reinforced plastic (CFRP) layer is modelled. The enhancement of the bearing capacity of the damaged structure compared to the undamaged structure is evaluated in the pre- and post-cracking regime. The main conclusion drawn from the numerical results is that the CFRP reinforcement is very effective for improving the integrity of RC cooling tower shells even when the latter present an advanced corrosion rate.

Determination of the boron concentration of OPR 1000 reactor critical state using the Cosi OPR1000 system

In the operation of a nuclear power plant (NPP), to adjust the capacity of NPP is necessary. When the NPP capacity is changed the nuclear fission is also changed. The methods used in changing the capacity of NPP include: changing the boron concentration, changing the position of the control rod groups, and changing the boron concentrations and the position of the control rod groups together. This report presents some results of the research, measurement boron concentrations when nuclear power plans OPR1000 critically state in the cases of ARO, ARI SB, ARI R1, R5 = 191 cm on the basis of the bisection method in the boron concentrations adjustment. The experiment is performed on core the simulator for OPR 1000 nuclear power plant. The results in the 4 cases were similar with NPP operating data using OPR1000 reactor.

Долгосрочное стохастическое прогнозирование мирового рынка ядерной энергетики

This article looks at the problem of devising a long-term developmental forecast of the nuclear energy market and the possibility of studying certain sections of the market. Bearing in mind the current state of the market and associated industries, it is particularly important to have a scientific approach to developing statistical forecasting instruments and methods with assessments of the dispersion of forecasts. is particularly important. The authors are the first to have developed and applied a probabilistic forecasting method for severala number of market indicators reflecting the physical size of the global nuclear energy industry for the period up to 2035, and in particular: the number and electrical capacity of reactors in service or taken out of service, and the demand for natural and enriched uranium and enrichment services. The forecasting relies on stochastic modelling of nuclear power plant (NPP) life cycles and operating characteristics, open nuclear fuel cycle parameters, and energy policy in corresponding regions around the world. Unlike scenario approaches, this model makes it possible to obtain probabilistic distributions of these characteristics, which is important when assessing the economic risks of various participants in the global nuclear energy market.The results obtained from the long-term forecast of NPP capacity dynamics for the world as a whole and for the largest regions of the planet are consistent with the scenarios of the World Nuclear Association (WNA) and the International Atomic Energy Agency (IAEA). These scenarios are developed on the basis of data provided by members of these organizsations, which confirms the reliability of the frequency distribution model used for key stages of the reactor life cycle. The authors have modelled the market’s probable new NPP construction volumes and NPP decommissioning volumes over the next 15 years in Russia, globally, and in certain world regions. The paper also presents an analysis of the likely capacity of the new Russian-made NPP construction market globally and its share of the global services map in this field up to 2030.

Study on the Coal-Based Synfuels System Coupled with Nuclear Energy

Coal-based synfuels plants are facing serious pressure on CO2 emissions reduction. Developing the coal-based synfuels system coupled with nuclear energy is an effective approach to reduce CO2 emissions. This work analyzes CO2 emissions features in the coal-based synfuels system, and further investigates three coupling paths between the coal-based synfuels system and nuclear energy. Subsequently, an inherent-safety and low-carbon coal-based synfuels system coupled with nuclear energy is proposed. In the coupled system, valley nuclear power is provided to conventional water electrolyser for hydrogen/oxygen production, and oxygen and hydrogen are supplied to the coal gasification and fuel synthesis processes, respectively. The simulation results show that the coupled system can reduce about 50% raw coal consumption and almost all CO2 emissions compared to the conventional coal-based synfuels system, meanwhile it can improve the peak shaving capacity of nuclear power plants.

Nuclear power for climate mitigation? Contesting frames in Korean newspapers

Korea has been one of the most aggressive countries pursuing nuclear power expansion, ranking in the top five nations globally for the installation capacity of nuclear power plants, nuclear power generation, and the number of reactors in operation. Even after the Fukushima accident, the Korean government has made no policy changes in regards to nuclear power, and public support for nuclear power remains relatively high. This study focuses on the role of the mass media in representing the Korean government’s benefit-oriented nuclear frame and the persistence of public support in the country for nuclear power. The study further aims to answer the following questions: What kind of frame was mobilized by the mass media? What kinds of speakers were chosen by the media to represent a particular side to the issue? A total of three conservative, progressive, and business newspapers were analyzed. The benefits and/or risks of nuclear power in the context of climate change were major topics in the three newspapers. The benefit and risk frame constructed in these three newspapers was characterized as “slightly risky but significantly beneficial” in the conservative Chosun Daily and MK Business and “seemingly beneficial but intrinsically risky” in the progressive Hankyoreh. Different frames were contested in the three newspapers; however, because the influential power of Korean progressive newspapers is weak, arguments supporting the growth and benefits of nuclear power have become pervasive in Korea.

SUNRISE – A caesura after nuclear has gone: Energy in Germany(and in other potentially de-nuclearizing countries)

The German Bundestag decided June 30, 2011 to shut down by 2022 stepwise the complete national nuclear power plant capacity which at the time of decision generated some 22% of the nation’s electricity demand. This presentation tries to present a technology forecast of three potential compensations 1) energy and exergy efficiency gains, 2) renewable energies, and 3) hydrogen energy, thereby bearing in mind that fossil fuels such as coal, mineral oil and natural gas will by no means be gone after that short 10 year transition time. Consequently, not only the three compensations, but also fossil fuels – now efficient to the technological utmost – have to meet the obligation of reducing anthropogenic environmental and climate changing influences, and, in Germany’s case with 75% of its energy demand covered by imports of great importance, try to decrease the almost life risking high import rate by distributing suppliers all over the world and start introducing global clean renewable energies and trade in renewable hydrogen energy. Whether SUNRISE will evolve into a paragon for all those nations thinking of, planning for, or already taking the first steps towards saying farewell to nuclear is too early to determine. The four components of energy sustainability compensating for nuclear – energy and exergy efficiency gains, clean fossil, solar and hydrogen – pluck up courage, make headway and leave nuclear behind. And, in particular, hydrogen energy is and will increasingly become humankind’s common cause!Two conclusions recapitulate the findings: “Activate what lies dormant” and “Remove barriers.”

Nuclear Power and Its Role in CO2 Emissions from the Electricity Generation Sector in Iran

Electricity demand in the Islamic Republic of Iran will continue to increase dramatically in the future due to the rapid pace of economic development leading to construction of new power plants. All forms of electricity generation have some level of environmental impact, such as air pollution, water resource use, water discharge, solid waste generation, and land resource use, and greenhouse gas emission. Concerns about greenhouse gas emissions affect decision-making about construction of new power plants. Comparison of different kinds of power plants indicates that nuclear power is not directly emitting greenhouse gas emissions. So nuclear power plants could be a suitable replacement for thermal power plants. Of course, renewable power plants could be used too, but the capacity of nuclear power plants is almost more than renewable power plants. Power plants in Iran are mainly thermal, burning fossil fuels, which emit a great deal of pollutants and greenhouse gases. The only nuclear power plant of Iran (Bushehr nuclear power plant) will be operating in 2009. This article attempts to interpret the role of Bushehr nuclear power plant in the CO2 emission trend of the power plant sector in Iran.

Transition to Low-carbon Electricity by 2020 In Guangdong, China: Pathways and Costs

ABSTRACT To address climate change, Guangdong has been chosen by the Chinese government as the setting of an experiment on low carbon transition. To analyze the transition, we investigated the development of the electricity supply system of Guangdong under different CO2 emission constraints. The investigation was carried out using a techno-economic model, built with the objective function of minimizing the total cost of the electricity supply system during the investigation. Results show that, considering costs, a 25% reduction (compared with 2007 levels) in CO2 emission from unit electricity supply by 2020 is possible. To achieve this target, several important actions are proposed. First, increasing the capacity of nuclear power plants to 24 GW may contribute 54.5% to CO2 emission reduction. Second, improving the efficiency of thermal power plants may contribute 33.6% to CO2 emission reduction; these efficiency measures include applying USC technology and decreasing the capacity of low-efficiency, coal-f...

Study on 3-D Flow Field of Concrete Volute Conduit of Circulating Water Pump in Nuclear Power Plant

As the largest unit capacity of nuclear power plant at present, the flow conduit of circulating water pump in EPR1750 nuclear power plant is a volute conduit, which is a cast-in-situ conceret structure with complexly gradual change cavity. Therefore, the hydraulic efficiency of circulating water pump is not only related with the design of pump leaves, but also closely related to the design of volute and the complicated spatial type of intake and outtake conduits. With the pump leaves and the intake and outtake conduits of conceret volute as the research model, based on computational fluid dynamics (CFD)and the three dimensional Reynolds averaged Navier-Stokes equations, an analytic model suitable for computation is established to simulate the three-dimensional steady flow in the whole pumping system under different operating modes. By use of the commercial fluid-computation softer ANSYS, the distribution of basic physic quantities in the fluid field inside the pump and the conduits is obtained. The analysis and prediction of the performance of pump system are made, and the spatial type design of intake and outtake conduits is evaluated. The calculation results can be referenced to improve the design of pump systems in the similar projects.

Prospects of nuclear power plants for sustainable energy development in Islamic Republic of Iran

This paper presents the feasible contributive share of electricity generation from each energy resources. This includes the economical feasibilities and all demographic projections involved in forecasting methodology, which explicitly reflect on overall national power demand projection in the Energy prospects of Islamic Republic of Iran till 2033. The Energy demand and reliability are presented with a view to elaborate on significant role and required capacity of Nuclear Power Plants (NPP) towards fulfillment of an energy mix policy in the country.