Multi-Fidelity Nuclear Power Plant Analysis through a Code-Agnostic FMI-Based Framework

Modeling primary and secondary coolant of a nuclear power plant system with a unique framework (MCUF)

Nuclear power plants (NPP) are subject to stiff requirements as to the cost effectiveness of their operation. However, since the NPP operation may be associated with the occurrence of severe environmental, social, political, material and other consequences as the result of nuclear and radiological accidents at NPPs, ensuring the specified level of the NPP safety is an operational task of the utmost importance. The current practice of the NPP design and operation suggests that the objectives involved in improving the efficiency of operation and those of ensuring the NPP safety level required by federal standards and regulations (NP-001) are achieved in isolation: no issues of ensuring high efficiency of the NPP operation are taken into account when addressing the issues involved in ensuring the safety of the NPP and, vice versa, it is a priori assumed that the required level of safety is ensured at any time when high efficiency of operation is achieved. The reason for this is the absence of procedures that make it possible to assess, in an integrated manner, the interdependence of economic and technological factors. The paper describes some of the methods to raise the efficiency of the NPP operation by selecting the best possible NPP maintenance and repair (M&R) strategies leading to high utilization and capacity factor values. A distinctive feature of the proposed techniques is that the efficiency of the NPP operation is proposed to be improved while ensuring at the same time the required level of the NPP safety with any NPP configuration.

A support vector machine integrated system for the classification of operation anomalies in nuclear components and systems

Traditional machine learning algorithms have problems such as overfitting, low accuracy, and difficulty in hyperparameter optimization when performing fault diagnosis.In order to improve the accident diagnosis ability of nuclear power plant reactor system, this paper combines Bayesian optimization (BO) algorithm with eXtreme Gradient Boosting (XGBoost) algorithm to develop a reactor accident diagnosis model.First, data preprocessing and feature quantity analysis are performed on accident data samples.Then, the BO algorithm is used to optimize the hyperparameters of the XGBoost model. Finally, the BO-XGBoost model is used to diagnose the operating conditions of seven nuclear power plants, and the diagnostic effects of various traditional machine learning classification algorithms are compared and analyzed.The results show that the BO-XGBoost model can achieve more efficient and accurate identification of reactor accident types, and the model has better generalization ability.This research can help nuclear power plant operators to accurately identify the types of reactor accidents, assist decision-making, and ensure the safe operation of nuclear power plants.

The energy supply of the future in the EU will be a mix of renewable, fossil and nuclear. There are 145 nuclear power reactors in operation in 15 out of the 27 EU countries, with installed power ∼132 GWe. The age distribution of current nuclear power plants in EU is such that in 2010 most of them will have passed 20-years and approximately 25% of them 30 years of age. The decrease of energy supply from nuclear generated electricity can not always be compensated in a reliable and economical way within a short time span. For this situation utilities may be keen to upgrade the reactor output and /or to ask their regulatory bodies for longer term operation. Under the research financed in the Euratom part of the Research Directorate (RTD) of the European Commission several projects explicitly address the safe long term operation of nuclear power plants (NULIFE, LONGLIFE) and the topics proposed in the 2010 call explicitly address issues concerning component ageing, in particular non metallic components, i.e. instrumentation and cables (I&C) and concrete ageing. This paper presents an overview of the plans for long term operation (LTO) of nuclear power plants in the EU. Special emphasis is given on research activities on component ageing management and long term operation issues related to safety.

Korea has been achieving the world best safety and economic performance of nuclear power plants through continuous technology development and asset management optimization since its first nuclear power reactor was introduced in the late 1970s. While most countries have stopped building new nuclear power plants since the severe accident in TMI nuclear plant in 1979, Korea has been steadily developing its own reactor models and constructing new nuclear plants. In addition, Korea won recent new nuclear plant project of United Arab Emirates (UAE) as a result of these efforts. A nuclear power plant consists of a great variety of complex equipment having state-of-the-art technologies, and the highest nuclear safety and equipment reliability are required. Therefore, the most sophisticated systematic engineering asset management is essential to the nuclear power plant. As a responsible company of operating and constructing all nuclear power plants in Korea, Korea Hydro and Nuclear Power Co. (KHNP) has developed its own asset management model for the nuclear power plants in operation and expanded the model into the new plants under construction. Since the asset management model was developed for the various equipment types in the nuclear power plant, it can be easily utilized in other industries as a highly effective asset management model. This paper presents new and innovative methods to refine and improve existing asset management practices in general plants by diagnosing KHNP’s physical asset management model. It contributes to the development and improvement of an advanced asset management model for general plant industries and utilities to meet the objectives of securing a clean environment, improved public health and safety, and general community well being.

Life extension beyond 60 years for the U.S operating nuclear fleet requires that instrumentation and control (I&C) systems be upgraded to address aging and reliability concerns. It is impractical for the legacy systems based on 1970's vintage technology operate over this extended time period. Indeed, utilities have successfully engaged in such replacements when dictated by these operational concerns. However, the replacements have been approached in a like-for-like manner, meaning that they do not take advantage of the inherent capabilities of digital technology to improve business functions. And so, the improvement in I&C system performance has not translated to bottom-line performance improvement for the fleet. Therefore, wide-scale modernization of the legacy I&C systems could prove to be cost-prohibitive unless the technology is implemented in a manner to enable significant business innovation as a means of off-setting the cost of upgrades. A Future Vision of a transformed nuclear plant operating model based on an integrated digital environment has been developed as part of the Advanced Instrumentation, Information, and Control (II&C) research pathway, under the Light Water Reactor (LWR) Sustainability Program. This is a research and development program sponsored by the U.S. Department of Energy (DOE), performed in close collaboration with the nuclear utility industry, to provide the technical foundations for licensing and managing the long-term, safe and economical operation of current nuclear power plants. DOE's program focus is on longer-term and higher-risk/reward research that contributes to the national policy objectives of energy security and environmental security . The Advanced II&C research pathway is being conducted by the Idaho National Laboratory (INL). The Future Vision is based on a digital architecture that encompasses all aspects of plant operations and support, integrating plant systems, plant work processes, and plant workers in a seamless digital environment to enhance nuclear safety, increase productivity, and improve overall plant performance. The long-term goal is to transform the operating model of the nuclear power plants (NPP)s from one that is highly reliant on a large staff performing mostly manual activities to an operating model based on highly integrated technology with a smaller staff. This digital transformation is critical to addressing an array of issues facing the plants, including aging of legacy analog systems, potential shortage of technical workers, ever-increasing expectations for nuclear safety improvement, and relentless pressure to reduce cost. The Future Vision is based on research is being conducted in the following major areas of plant function: (1) Highly integrated control rooms; (2) Highly automated plant; (3) Integrated operations; (4) Human performance improvement for field workers; and (5) Outage safety and efficiency. Pilot projects will be conducted in each of these areas as the means for industry to collectively integrate these new technologies into nuclear plant work activities. The pilot projects introduce new digital technologies into the nuclear plant operating environment at host operating plants to demonstrate and validate them for production usage. In turn, the pilot project technologies serve as the stepping stones to the eventual seamless digital environment as described in the Future Vision.

Further increase of the reliability and efficiency of the operation of nuclear power plants depends on the comprehensive solution of many problems, of which the problem of optimization and increase of the informativeness of chemicotechnological monitoring is gaining in importance. There is a clear rift between the level of scientific ideas and technical solutions on which nuclear power plants are based and the existing approach to the organization of chemical monitoring. Everyone understands the necessity of chemical monitoring, but many people do not regard it as a necessary element for ensuring normal operation of a nuclear power plant. The lack of standard requirements and a standard methodical base markedly lowers the reliability of the results of analyses, and behind this lies possible breakdowns of the water-chemical conditions. How can this situation be explained? The consequences of deviations of water-chemical conditions from regulation standards are by no means manifested immediately. Apparent wellbeing at any given time creates the impression that the requirements of the chemical laws can be ignored with impunity. But there is also another reason for the disdainful attitude toward chemical monitoring. Chemical-technological monitoring at a nuclear power plant reduces to the determination of ~20 water-quality indicators for the basic and auxiliary systems. Considering the number of existing points at which samples are extracted in each block of a nuclear power plant and the frequency with which the analyses are performed, it is not difficult to imagine the impressive number of the overall volume of data obtained. Thus the total number of analyses per month for one block of a nuclear power plant with RBMK-1000 approaches 15,000 [i]. In addition, as a rule, these are single measurements, whose error it is virtually impossible to estimate exactly. Moreover, regardless of how conscientious the chemists-analysts at the technological laboratories are, in the monotony of repeating values it is difficult to escape big blunders in the case of unforeseen deviations of the parameters in the water-chemical conditions. Under these conditions there is no hope of obtaining reliable information for each of the measurements, making sense of the observational results, and drawing correct conclusions. We arrive at a p~r~dox, By increasing the number of parameters monitored and the number of points at which samples are extracted we strive to increase the information content of chemical monitoring, but we actually achieve the opposite result. At the present time, when nuclear power has transformed from a unique source of energy to one of the most important elements of the power production in the country, it is essential to reexamine the concepts forming the basis for the implementation of chemical-analytical monitoring at nuclear power plants. At the first nuclear power plants the research and technological functions of analytical monitoring were balanced, and preference was often given to obtaining research information. For serially produced nuclear power plants research programs are a rare episode. It is evident that the main reason for this situation is hidden in the existing standards and requirements imposed on the chemical monitoring system at nuclear power plants. At the first stages of development of nuclear power the striving toward performing as much analysis as possible and over the entire technolgocial loop was justified, whereas at the present time, as experience in operating nuclear power plants in this country and abroad shows, the time has come to search for new approaches to the problem of analytical monitoring of the quality of water heat carriers. The successful solution of the problem of analytical monitoring is often linked primarily with the instrumentation. But the number of methodical and instrumentation developments continues to increase, and the chemical-technological monitoring remains as before one of the laborious and unreliable elements in the overall chain of operational monitoring of nuclear power plants. Fundamental restructuring of the overall scheme of such monitoring is possible only based on automatic or, at least, automated means of chemical analysis.

Nowadays, the nuclear island and conventional island make use of sea water to cooling in most of nuclear power plant, in order to maintain the heat dynamic balance of nuclear power plant, and to protect the safety of nuclear power plants. As a result, the safety of the cold source system for nuclear power plant production and operation has a very important role. In this paper, by analyzing the threat of external factors (such as sea creatures) for nuclear power plant cold source system reliability, discuss how to enhance the ability of prediction and prevention of nuclear power plant. Through the establishment of sea creatures threat prediction mechanism with the complement of the original cold source equipment and emergency management mechanism, to build a safe security system, and to improve the cold source system operation.

Hi Reddit! My name is Phil Sharpe and I am here today with a few of my colleagues from Idaho National Laboratory (INL) and the Gateway for Accelerated Innovation in Nuclear (GAIN). This is Nuclear Science Week, so we thought it would be great to start a conversation about the future of advanced nuclear energy, including reactor designs, fuel types, industry engagement, and some of the ideal uses for advanced nuclear systems. Commercial nuclear power currently provides nearly 60 percent of the U.S. emission-free power, according to the Nuclear Energy Institute. INL is the U.S. Department of Energy's lead nuclear energy laboratory. INL experts are developing, testing and demonstrating new fuels and materials, reactor systems, advanced nuclear energy system applications, plant monitoring and safety systems, and waste management options. The scientists participating in today's AMA: Phil Sharpe​​, Ph.D., director of Nuclear Systems Design & Analysis Rita Baranwal, Ph.D., director of the Gateway for Accelerated Innovation in Nuclear (GAIN)​ ​Hans Gougar​, Ph.D., director of the Advanced Reactor Technology Technical Development Office at INL George Griffith​, Ph.D., INL Manager for Small Modular Reactor Deployment​ ​Brenden Heidrich, Ph.D., Chief Irradiation Scientist, the Nuclear Science User Facilities (NSUF)​ Some fodder for discussion: • The Potential for Disruptive Innovations in Nuclear Power - http://pubs.cnl.ca/doi/full/10.12943/ANR.2014.00033 • What Will Advanced Nuclear Power Plants Cost? - https://www.eenews.net/assets/2017/07/25/document_gw_07.pdf • Advanced Test Reactor Options Study - https://art.inl.gov/INL%20ART%20TDO%20Documents/Advanced%20Demonstration%20and%20Test%20%20Reactor%20Options%20Study/ADTR_Options_Study_Rev3.pdf • Global Nexus Initiative Reports on nuclear energy – http://globalnexusinitiative.org/category/results/reports/ We’ll be back at 11 a.m. EST (9 a.m. MST) to answer your questions, ask us anything!

With the development of civilization and the growth of the world’s population, the need for electricity also increases. Today, the main electricity sources are nuclear power plants (NPPs) and hydroelectric power plants (HPPs) that run on hydrocarbon fuels such as coal, peat, gas, and fuel oil. But these generating electricity methods have serious drawbacks, for example, the depletion of hydrocarbon natural resources, which leads to their shortage and rise in price. Nuclear and hydroelectric power plants cannot fully cover the need for electricity. In addition, the tragic events in the history of nuclear energy, e.g., the accident at the Chernobyl nuclear power plant, the nuclear power plant disaster in the city of Fukushima, etc., show great risks associated with the operation of nuclear power plants. Thus, solar energy engineering is the most efficient type of alternative, safe energy in the foreseeable future of mankind. This review is an effort to highlight the major progress and future challenges of using renewable energy sources.

This paper explores the effectiveness of the nuclear disaster management system in Taiwan via a review of the third (Maanshan) nuclear power plant. In doing so, the Fukushima Daiichi nuclear disaster in Japan on 11 March 2011 is reviewed and compared with the situation in Taiwan. The latter's nuclear disaster management system is examined with respect to three key variables: information; mobilisation; and inter-organisational cooperation. In-depth interviews with 10 policy stakeholders with different backgrounds serve as the research method. The results point up the need for improvement in all dimensions. In addition, they highlight three principal problems with the nuclear disaster management system: (i) it might not be possible to provide first-hand nuclear disaster information immediately to the communities surrounding the Maanshan facility in Pingtung County, southern Taiwan; (ii) the availability of medical resources for treating radiation in Hengchun Township is limited; and (iii) the inter-organisational relationships for addressing nuclear disasters need to be strengthened. Hence, cooperation among related organisations is necessary.

The T-junction is widely used in nuclear power plant systems. In order to ensure the normal operation of nuclear power plant, it is very important to study the onset point of T-junction liquid entrainment. Previous researches on the onset point of liquid entrainment have been lucubrated, but most of them are for small branch pipes. This paper is about the onset law of large branch pipe. In addition, the effect of branch angle and branch size on the onset point of liquid entrainment was analyzed by comparing with other branch pipe sizes in this paper. The onset phenomenon of liquid entrainment is described and the effect of angle on onset is studied in this research. It is found that the effect of branch angle on the onset point of entrainment is consistent with that of other sizes: as the angle between the branch pipe and the horizontal direction decreases, the onset needs greater Frg on condition of the same hb. The reason is that the decrease of the inertial force in the vertical direction acting on the liquid phase by the gas phase as the angle decreases. In addition, by comparing with the onset point law of liquid entrainment with different branch pipe sizes, we found the effect of branch pipe size on the onset is that the smaller branch pipe needs the greater gas velocity when onset occurs. The reason is that there is different flow resistance of different sizes of branch pipe.

With growing concerns about global warming, building more nuclear power plants is becoming one of the inevitable options to provide the world’s electricity. This is mainly because nuclear power is considered as the major source of “carbon-free” energy. Currently, extensive preventive maintenance, inspection, andmonitoring programs are developed to ensure safe and reliable operation of nuclear power plants. These programs involve safety analysis codes, equipment health monitoring, degradation-specific inspections, and plant lifecycle management (PLM). Although extensive effort has been invested to develop such programs, nuclear power plants continue to experience problems and therefore more accurate analysis and related researchwork still receive a great attention. This is mainly because the unresolved safety problems or lack in systems monitoring often causes significant safety-related events at nuclear power plants. Therefore, the demand for applied research work continues to grow in order tomitigate such events, increase the plant capacity factor, and gain public support for nuclear power as an alternative power source. This special issue identifies and analyzes major practical problems in nuclear energy and it contains 7 articles out of 14 articles that were initially received for publication. Even with the limited number of articles presented in this special issue, a wide range of topics are covered to present different experiences from several nuclear power plants and research institutions around the world. These topics are gathered in this issue to present the best engineering analyses, research effort, and practice with as little prejudice as possible. The issue starts by the novel method for optimization of the maintenance activities presented by A. Volkanovski and L. Cizelj in the nuclear power plant in order to improve plant safety. The authors consider different constraints on the optimization of the maintenance activities in the nuclear power plants. Three severe accident sequences of nuclear plants are discussed by G. Shao et al. to show that the natural circulation phenomenon results in heat transfer from the core to the pipes in RCS and consequently may cause the creep rupture of pipes in RCS and delay the severe accident progression. Also, S. Liu et al. were able to show that thermal stress failure caused by alternating operational loads is one of the important damage mechanisms in the nuclear power plants. Furthermore, R. K. Ur et al. discuss the impact of instrumentation and control components on the architecture of reactor protection systems. On the numerical and statistical analysis side, the article of S. U.-D. Khan et al. presents a modification to the neutron kinetics code, which originally works for the cylindrical type fuel elements, to plate type fuel nuclear reactor. Moreover, the study performed by M. El Nakla et al. has stressed the importance of the local scale observation leading to better understanding of the CHF phenomena in large pipe. They were able to predict the occurrence of critical heat flux in horizontal tubes using an extra correction factor to account for flow stratification. Finally, T. H. Woo contributed to this special issue with a paper on the nuclear power plant security. He presented dynamical assessment, which helps operator to find the dangerous situation in the site and avoid possible incidents that could be a catastrophe for theNPPs.We believe that this special issue provides interesting information on the recent progress in nuclear power research.

In 2017, 449 nuclear reactors were operating for electricity generation in the world. More than 60% of all reactors were represented by pressurized water reactors. One of the most modern reactors of this type is the AP1000 reactor, developed by Westinghouse. The mentioned construction is also taken into account in terms of the construction of the first nuclear power plant in Poland, for both economic and technical reasons as well as safety systems, which have been very extensive and implemented in this construction. In the following paper, apart from the presentation of the nuclear power plant technology system, model of AP1000 reactor was presented. Above mentioned model allows, among other things, to investigate the influence of fuel assemblies locations on the effective neutron multiplication factor/reactivity. In addition, the relation between moderator and neutrons energy was examined (the neutron flux density was determined as a function of energy) and the amount of fission products generated in the reactor core during normal operation was presented. The obtained results were analysed and referenced to the literature data in order to verify the created model.