Nuclear Power Operation Research Articles

Design and Development a Software for Wear Measurement of Control Rod Guide Card Based on Machine Vision

The control rod guide tube (CRGT) is used to protect the rod cluster control assembly (RCCA) from bending while providing guidance for the up and down movement of the RCCA. This ensures that the dropping time of the RCCA meets nuclear safety requirements and stops nuclear reactions within the specified time frame. During the up and down movement of the RCCA, the control rod guide cards (CRGC) may experience axial and vibration wear. If the wear is severe, the CRGC may lose its guiding function, resulting in serious problems such as delayed dropping time. In this paper, a machine vision method is proposed to measure the dimensions of the CRGC. Edge extraction, image rectification, and template matching are used to realize autonomous measurement of the CRGC based on its features. The developed measurement software has been used 5 times in domestic nuclear power plant overhauls and has detected 15 CRGTs that were close to the wear limit. This provided data support for the replacement of the CRGTs and effectively improved the quality of nuclear power operation.

The principles of issuing a crucial decision (selected problems)

The erection and commissioning of a nuclear power plant requires a number of administrative pro­cedures. At the same time, in the majority of cases, it concerns proceedings that are mainly regulated outside the provisions on nuclear energy, and thus have already been discussed many times in the doctrine (e.g. cases regarding the building permit). Against the background of the above, the procedure for issuing a crucial decision stands out. This is because this decision is not present outside the regulations concerning nuclear energy. However, it should be noted that the decision in question is of key importance as far as the possibility of starting the construction and operation of nuclear power is concerned. Thus it is surprising that the manner in which this ruling is regulated does not allow for determining such basic issues as the character of the crucial decision or the premises for issuing it. The goal of this study is to solve these dilemmas. The adopted research method is the dogmatic and legal method. On the basis of the conducted analysis, it was established that in the current legal status, the crucial decision is of a binding nature, and the premises for its issuance are included in Article 22 Section 3 of the Act of 29 June 2011 on preparing and implementing investments in the field of nuclear power facilities and accompanying investments. It should be added that the presented results of the interpretative analysis are inconsistent with the position of the doctrine. In the literature, it is assumed that the crucial decision has a discretionary (‘political’) character. Moreover, the wording of the aforementioned act does not specify the conditions for issuing a crucial decision. Instead, it is suggested to look for them within the so-called legislative materials.

Dispatch analysis of flexible power operation with multi-unit small modular reactors

The relevance of nuclear power plant flexible power operation (FPO) is rising due to increased penetration of variable renewables. Small Modular Reactors (SMRs) such as NuScale are envisaged to have multiple units on one site. This provides opportunities for coordinating FPO between units, but also introduces challenges as common services (e.g., refueling equipment) must be shared between units and fuel loadings may be standardized. It is therefore important to quantify whether FPO with SMRs is economically beneficial. This paper quantifies the economics of FPO on different timescales to analyze refueling outages of such multi-unit SMRs. A 24-h price-taker profit maximization of SMR operation is first solved considering revenues from wholesale power and ancillary service (AS) markets. The results are then used to find the most profitable operation strategy over several years for multiple units at the site accounting for the physics and materials limits on NPP operation, including refueling outages. Results show a small but appreciable participation of nuclear into AS, contributing 4% of revenues. Due to the longer fuel cycle, over a decade of operation the units’ refueling outages drifted by 3 months, ultimately leading to refueling during summer.

The reliability analysis of pressurized water reactor safety injection system based on GO-FLOW

The safety injection system (RIS)is a large and complex fluid system in a nuclear power plant. Its central role is to ensure the safety of the core in the event of a breach event in the first circuit of the nuclear power plant. In order to investigate the timing of the safe injection system at the time of a Small-Break Loss-Of-Coolant Accident (SBLOCA), this paper uses the GO-FLOW method to model seven time points in the three operational phases of the safe injection system. The calculation is completed in conjunction with the failure rate of each component to give the reliability of the RIS at each point in time at SBLOCA. The final analysis yielded low reliability at the beginning of the direct cold section injection phase, which is of great reference for subsequent equipment maintenance and the safe operation of nuclear power.

Nuclear Power Sustainability Path for China from the Perspective of Operations

Nuclear power, as a low-carbon, stable, and efficient energy, plays an important role in replacing fossil fuels in the development of a globally sustainable energy system. However, nuclear power has deviated from the path to achieve the Sustainable Development Goals of the United Nations. The path of sustainable nuclear power for China was proposed based on an analysis of the development of global nuclear power and the situation in China, using advanced operation concepts and intelligent collaboration technology to change the labor-centered operation mode. It serves as a model for other countries with a labor-centered nuclear power operation mode and an aging society seeking to achieve carbon neutrality through the use of nuclear power around the world.

Friction Performance Analysis of Reactor Coolant Pump Shaft Seal Based on Sensor and Computer Simulation

In recent years, the state has put forward a grand plan to develop nuclear power in order to control environmental pollution and carbon emissions. In nuclear power plants, mechanical seals for reactor coolant pump play an important role in nuclear power safety production. However, China cannot independently produce such mechanical seals, and they are blocked by foreign related technologies, which has seriously affected China’s nuclear power development plan and the overall safety of China’s nuclear power operation. Under this background, this paper studies the friction performance of the shaft seal of the reactor coolant pump, uses the sensor to obtain the data of friction factors such as low-pressure leakage, effectively monitors the low-pressure leakage through calculation and simulation modeling, truly reflects the operating state of the reactor coolant pump, and provides a new research direction and experimental basis for further analysis of the friction performance of the shaft seal of the reactor coolant pump. The results show that under the joint action of the pressure difference and the force generated by the deformation of the moving ring plate, the cone angle formed on the seal end face is 1300.9 μ convergence gap of rad. When the inlet water temperature is 65°C, the leakage rate is 1867.8 L/h. The deformation of the moving ring deformation ring plate can hinder the increase of the deformation cone angle of the moving ring. The greater the thickness of the moving ring deformation ring plate, the greater the seal leakage rate. The inlet temperature of the sealing medium and the friction performance of the material also have an impact on the sealing performance.

Joint Operation Modes and Economic Analysis of Nuclear Power and Pumped Storage Plants under Different Power Market Environments

Given the continuous promotion of power market reforms, the joint operation modes and economic analysis of nuclear power and pumped storage hydropower under different market mechanisms are the key to ensuring the low-carbon and economic operation of the power system. First, this study constructed the power expansion optimization model and put forward the allocation ratio by combining the operation characteristics of nuclear power and pumped storage. Second, a simulation model for the joint operation was established to optimize their operation modes. Finally, the joint operation modes and a method for calculating profitability under different power market mechanisms were proposed. A case study in the FJ power grid reveals that the joint operation of nuclear power and pumped storage can increase the annual utilization hours of nuclear power by 1000 h, reduce the operation cost of pumped storage, and increase the market competitiveness of the system. With the improvement in the power market, the joint financial internal rate of return of the system would increase gradually to 11.40% in the long-term mature market. This indicates that the power market reforms would ensure the profitability of the joint operation of nuclear power and pumped storage.

Analysis of the impact of China’s energy industry on social development from the perspective of low-carbon policy

The energy industry is one of the industries with high energy consumption, high pollution and high emissions in China. Low-carbon policies in the energy sector have a vital impact on China’s carbon reduction, climate change response and social development. In 2021, China’s energy status is mainly coal, accounting for about 56% of the total energy consumption. After 20 years of rapid development of clean energy in China since the 21st century, China’s wind power generation currently ranks first in the world, and the installed capacity of newly added wind power generation equipment is the largest. In terms of solar energy, China has more than 400 photovoltaic (PV) companies, and China-made solar PV panels have accounted for more than 70% of the global market share, with its own total installed capacity reaching 253.3GW. A total of 52 nuclear power units have been put into commercial operation in Mainland China, with an installed capacity of 53,485.95MWE. In terms of nuclear energy, the accumulative power generation of commercial nuclear power units accounts for about 4.99% of China’s accumulative power generation.11On October 29, 2021, China Nuclear Energy Industry Association released the operation of nuclear power in China from January to September. In addition, this paper takes the power industry as an example to study the low-carbon policy of China’s energy industry. By using the policy text mining method to analyze the original text types, high-frequency words and implementation effects of 96 selected policies, the social impact of low-carbon policy on carbon reduction effect, green finance development, residents’ health, job creation and some energy-consuming enterprises is obtained. This paper puts forward targeted suggestions to provide effective reference for China’s relevant policy making.

Consistency guaranteed two-timescale decision and optimization of HVAC system with ice storage

Nuclear power is the world’s largest source of clean energy. Nowadays the capacity shortage of electricity market for consuming nuclear power has appeared. Meanwhile, under the unique environment of high humidity and high salinity of nuclear power plant, the environment should be improved to ensure staff comfort and equipment safe operation through heating, ventilation, and air conditioning (HVAC) system. The joint operation of nuclear power and ice storage should be encouraged. Using nuclear power to provide electricity, the ice storage uses cheap off-peak electricity to make ice and uses the ice for supplemental cooling during peak demand time. The ice storage also provides a way to shift a large amount of electricity from off-peak time to peak time. With the objective of minimizing the electricity cost, while keeping the indoor temperatures of nuclear power plant near the desired temperatures, a two-timescale model of HVAC system with ice storage is proposed in this paper. Simulation results show that the proposed model can guarantee the consistency in different timescales, and meet the user desired temperature for comfort with the electricity cost reduced.

Organizing Industrial Construction of Nuclear Power Facilities in the Global Nuclear Power Markets taking into account Reliability Simulations from Pre-Investment Stages

This article considers the problem of ensuring the growth of export capacities of the industrial construction of nuclear power facilities in the global markets through the simulation and management of the organizational reliability during the pre-investment stage. This research is made relevant by a high level of uncertainty in the implementation of international investment projects for nuclear power when over 60% of the world’s nuclear reactors are constructed with delays and at increasing costs. The purpose of this research is to develop methodological approaches and practical recommendations on the modeling and complex management of organizational reliability indicators for the industrial construction of nuclear power facilities in the global markets during the pre-investment stages. This article presents the following results: the simulation procedure for the organizational reliability and life cycles of the industrial construction of nuclear power facilities developed by the authors, development specifics and trends for this type of industrial construction, recommendations concerning the organization of industrial construction to improve the reliability of nuclear power facility construction based on a managed factor space and multi-criterion optimization of calendar schedules. The conceptual approach to modeling and management of the organizational reliability of nuclear power industrial construction and operation life cycles in question can be determined as a promising market tool that can be used to regulate the increase of the competitive abilities of the Russian branches of Rosatom State Corporation. This stipulates facilitating the growth of the industrial construction of nuclear power facilities in the global market from the current share of Rosatom State Corporation of 26% (120 billion USD) to 40-50% before 2035 through the improvement of the organizational reliability of the implementation of this type of investment projects.

Research and Realization of Virtual-Real Control of Robot System for Off-Heap Detector Assisted Installation Based on Digital Twin

In order to explore the application of digital twin technology in the operation and maintenance of nuclear equipment, based on the installation and replacement of out-of-core detectors in the nuclear power plant of the Guohe No. 1 demonstration project, a digital twin system of robots for auxiliary installation of out-of-core detectors based on digital twins is proposed. Taking the process of the robot transporting the out-of-core detector as the research object, a digital twin of the robot is established, and the two-way interaction between the twin model and the control system is realized by using the ADS(Automation Device Specification) communication protocol. The experimental results show that the system has high feasibility and can provide a basis for the transparent and real-time visualization of the robot operation process. Therefore, the application method of digital twin technology proposed in this paper can serve the operation and maintenance of nuclear power, and is of great significance to promote the digital transformation of nuclear power in my country.

Peak shaving benefit assessment considering the joint operation of nuclear and battery energy storage power stations: Hainan case study

The rapid development of battery energy storage technology provides a potential way to solve the grid stability problem caused by the large-scale construction of nuclear power. Based on the case of Hainan, this study analyses the economic feasibility for the joint operation of battery energy storage and nuclear power for peak shaving, and provides an effective solution framework for construction scale and battery type determination. Under the proposed framework, a novel cost model for the large-scale battery energy storage power station is proposed. Then, economic analysis is conducted to get the most economical battery type and construction scale by considering the comprehensive economic benefit of the joint operation under the limit of the load factor. On this basis, sensitivity analysis of economic indicators to control parameters and economic parameters is performed to further demonstrate the economic feasibility of the joint operation. Comparative analysis shows that 270 MW lithium iron phosphate battery energy storage power station has the best and stable comprehensive performance in terms of the IRR, PBP and LCOE, which are 16.27%, 6.27 year and 0.464¥/kWh, respectively. In comparison with the pumped storage, the battery energy storage has lower initial investment, faster capital recovery and smaller floor area under the joint operation mode. Moreover, sensitivity analysis illustrates that the large-scale application of battery energy storage still depends on the trade-off between the cost performance of battery and the real-time electricity price.

Экология и энергетика будущего

Object and purpose of research. The object of the research is the influence of the world power industry on the ecology and safety of human and nature. The purpose is to identify ways of energy industry development based on the basic criterion of "harmony with nature". Materials and methods. Analysis of regulatory documents, literature, Internet sources, calculation systematization and classification of statistical data. Main results. A convincing evidence base has been provided for the vector of world power engineering development based on the active replacement of hydrocarbons by nuclear energy. Conclusion. Conclusion. Global warming and the energy crisis are just around the corner, and only nuclear power can solve these problems, providing humanity's increasing energy needs in harmony with nature. The main question today is not related to technology, but to psychology. The task is to systematically form public opinion about the safe operation of nuclear power.

Exploration on planning and development of pumped storage power stations in China

Our country has a vast territory and a large population, with the rapid development of economic society, electricity load continues to grow, and the difference between peak and valley load continues to grow also. Pumped Storage Power Station is the most mature large-scale energy storage method at present, and it is an important part of the new power system with new energy as the main body. In order to adapt to the rapid development of wind power, solar power and other new energy, and meet the requirements for safe and stable operation of nuclear power, ensure the safe and reliable operation of the power system, it is necessary to reasonably support and accelerate the construction of pumped storage power stations.

A rapid coupling method for calculating the radiation field in decommissioning nuclear power plants

The decommissioning of nuclear facilities in nuclear power plants require a rapid dose estimated method. In the past, dose estimation methods include the deterministic and stochastic methods, which have some defects that polarize the computation overhead or accuracy. To address this, we proposed the Monte Carlo–point kernel (MC-PK) coupling method. This paper establishes a nuclear power plant model and uses the nuclear reactor's available power operation history to calculate device source data. For comparison, the radiation field has been calculated using both the Monte Carlo method and the MC-PK coupling method. The comparison result demonstrates that the MC-PK coupling method's calculation time is much less than that for the Monte Carlo method and the mean absolute percentage error of MC-PK relative to MCM is 24.92%. This study provides a viable strategy for the real-time radiation field calculation of decommissioning nuclear facilities.

РАЗРАБОТКА МОДЕЛЕЙ, АЛГОРИТМОВ И ПРОГРАММНОГО КОМПЛЕКСА ДЛЯ РЕШЕНИЯ ЗАДАЧ ОЦЕНКИ РИСКА НА АЭС ПРИ ЗАПРОЕКТНЫХ АВАРИЯХ

A project is aimed at the development of models, algorithms and a program complex to carry out measures for safety increase and risk decrease during development of new nuclear power plants (NPP) and operation of working nuclear power ones. A basic novelty of the project is the development of a methodical apparatus for the estimate a radiation risk at NPP in case of the most dangerous (beyond-design) failures with the emission of origins of thermal neurons with the low density of a flow. 
 Atomic piles based on the use of fission energy of heavy nuclei fission are powerful sources of gamma and neuron radiation. The project is aimed at the computer modeling and development of new methods, algorithms and a program complex for the problem solution in the estimate of safety and risks at NPPs at the most dangerous (beyond-design) failures with the emission of thermal neurons sources with the low density of a flow. To realize the project it is necessary to develop a methodical approach to the solution of problems in the estimate of doses of external and internal irradiation and the estimate of damage for the population living around NPPs at the most dangerous (beyond-design failures with the emission of thermal neurons sources with the low density of a flow taking into account a population age structure. On the basis of these solutions there will be offered measures to decrease a risk and safety increase NPP safety.

Euratom Research and Training in 2019: challenges, achievements and future perspectives

The development and safe operation of nuclear installations in Europe is of vital importance for the future of nuclear energy. Helping to ensure the safe operation of nuclear power has always been one of the top priorities of Euratom Research Framework Programmes. With the incentives of Horizon 2020, further integration towards an EU/Euratom Research Area was achieved, better prioritisation at European and International levels based on updates of Research and Innovation agendas or deployment strategies, capitalisation of European Technology platforms and enhanced cooperation with International Organisations or Fora effectively happened. Evolutions towards European Joint Programmes together with EU/Euratom Member States, confirm that research and innovation programmes successfully benefit from a truly added value of a concerted European approach in nuclear safety research and training advocated by the European Commission and EU/Euratom Member States.

Acoustic Evaluation of Fishery Resources in Seawater Reservoir and Water-Intake Open Channel of Taishan Nuclear Power Plant

The CGN Taishan NPP seawater storage is a land-sealed type and is connected to the open water intake channel of Dajin Island in the open sea through a subsea tunnel. Due to the impact of large-scale facility aquaculture in the nearby seas, fish spawning grounds have been formed in this area, and fish breeds faster. A large number of fish have impacted on safe operation of nuclear power. In response to this situation, this study conducted acoustic navigation surveys of fish resources in most waters of the “Sea Reservoir” and “Water intake channel”, using broadband scientific fish finder system (EK80, 120kHz, 200kHz) produced by Norwegian Simrad Company. Evaluation of acoustic resources using echo integration method. The survey scope of seawater storage in this survey is from the entrance to the first barrier (around a distance of 760m) and from the first barrier to a second barrier (around a distance of 220m); the survey distance of the water intake channel is about 1460m. From the echo image, it can be found that the zooplankton in the sea reservoir is much smaller than the water intake channel, and the fish size of the water intake channel is much larger than that of the sea channel.Acoustic data was processed and analyzed using Echoview software to calculate the average SV and detect the strength of the single target. The results show that in the survey area of the Taishan Nuclear Power Plant Hai Reservoir, the total number of fish is about 1.38 million, the total weight is about 13.6 tons, and the fish with a body length of less than 20cm is the majority, and there are fewer large-sized fish; The total resources in the survey area is about 47 tons, with a total number of 27 million, and has a high density.

The unified model for irradiation embrittlement prediction of reactor pressure vessel

The irradiation embrittlement of reactor pressure vessel (RPV) steel is the top priority for nuclear power operation safety. In this work, neutron irradiation experiments were performed on a commercial RPV steel at a high temperature using a neutron irradiation experimental reactor, then the mechanical and electromagnetic properties measurements were performed in a hot laboratory. The results show that there is a unified exponential function relationship between the variability of mechanical and electro-magnetic properties for RPV steels during neutron irradiation embrittlement, and the fitting accuracy results show that the prediction unified model is scientific, practical and effective. The theoretical basis of prediction unified model is that both mechanical and electromagnetic properties are external manifestations of the microstructure evolution for RPV under neutron irradiation. Finally, this paper points out that based on the prediction unified model, it can be developed into a non-destructive evaluation technique for RPV irradiation embrittlement with many advantages.

Multi-Power Joint Peak-Shaving Optimization for Power System Considering Coordinated Dispatching of Nuclear Power and Wind Power

The matching characteristics of wind power output and nuclear power peak shaving are studied and the influence of coordinated dispatching of wind power and nuclear power on peak shaving flexibility and cost of the power grid is analyzed. Taking the lowest total operation cost of the system as the objective and considering the operation constraints, peak shaving cost of nuclear power units and the abandoned wind cost, a multi-power dispatching model for power system is proposed. In addition, in order to accurately optimize the output of nuclear power, a method of subdividing the peak shaving depth of nuclear power to linearize the constraint of nuclear power peak shaving is proposed. The analysis of example shows that the multi-power dispatching model considering the coordinated operation of wind and nuclear power has a high operation economy and can significantly reduce the amount of wind abandonment. The daily load tracking mode can be used for the participation of nuclear power units in daily peak shaving and the feasibility and necessity of coordinated wind-nuclear dispatching are verified.