Download or read book Investigation of Reliability Growth in the Nuclear Industry for Probabilistic Risk Assessment written by Hyunsuk Ahn and published by . This book was released on 1992 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current method of determining component failure rates for probabilistic risk assessment (PRA) in the nuclear industry is to take the total number of failures divided by the time over which the failures occurred. The method proposed in this study is the reliability growth method and involves taking into account the fact that the amount of failures per additional year of operation generally decreases yearly because the operational staff becomes familiar with the equipment. The reliability growth method will result in lower component failure rates which when used in PRA studies could result in a lower core melt frequency value. The component failure rate would be expected to be higher in the early stages and should gradually decrease as time goes on. This study will compare the final core melt frequency of the Trojan Nuclear Power Plant using both methods. The Nuclear Power Reactor Data System (NPRDS) data base from the Institute of Nuclear Power Operations (INPO) was used in this study. The components which were examined for the reliability growth method are motor operated valves, service water pump/motors and emergency diesel generator air chargers. These data were screened to ensure that only true failures were reported. A comparison was made of the overall core melt frequency between the conventional failure rate method and reliability growth method for the motor operated valves. The overall core melt frequency was decreased by 1.8 % when using the reliability growth method compared to the conventional method.
Download or read book Risk and Safety Analysis of Nuclear Systems written by John C. Lee and published by John Wiley & Sons. This book was released on 2012-01-12 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book has been developed in conjunction with NERS 462, a course offered every year to seniors and graduate students in the University of Michigan NERS program. The first half of the book covers the principles of risk analysis, the techniques used to develop and update a reliability data base, the reliability of multi-component systems, Markov methods used to analyze the unavailability of systems with repairs, fault trees and event trees used in probabilistic risk assessments (PRAs), and failure modes of systems. All of this material is general enough that it could be used in non-nuclear applications, although there is an emphasis placed on the analysis of nuclear systems. The second half of the book covers the safety analysis of nuclear energy systems, an analysis of major accidents and incidents that occurred in commercial nuclear plants, applications of PRA techniques to the safety analysis of nuclear power plants (focusing on a major PRA study for five nuclear power plants), practical PRA examples, and emerging techniques in the structure of dynamic event trees and fault trees that can provide a more realistic representation of complex sequences of events. The book concludes with a discussion on passive safety features of advanced nuclear energy systems under development and approaches taken for risk-informed regulations for nuclear plants.
Download or read book Reliability and Probabilistic Safety Assessment in Multi Unit Nuclear Power Plants written by Senthil C. Kumar and published by Academic Press. This book was released on 2023-02-09 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reliability and Probabilistic Safety Assessment in Multi-Unit Nuclear Power Plants presents the risk contributions from single and multi-unit Nuclear Power Plants to help aggregate the risks that may arise due to applicable hazards and operating states. The book combines the key features of multi-unit risk assessment in one resource, reviewing the practices adopted in various countries around the globe to exemplify the dependencies between units on a site. These dependencies include multi-unit interactions, environmental stresses, the sharing of systems, and the sharing of human resource in a control room, factors which can all introduce an increase potential for heightened accident conditions. This book helps readers systematically identify events and evaluate techniques of possible accident outcomes within multi-units. It serves as a ready reference for PSA analysts in identifying a suitable site and the sharing of resources, while carrying out multi-unit risk assessments to ensure the safety of the public and the environment. It will also be valuable for nuclear researchers, designers and regulators of nuclear power plants, nuclear regulatory agencies, PSA engineers and practicing safety professionals. Provides a framework for nuclear and PSA researchers and professionals on the design and operation of multi-unit risk assessments Reviews practices adopted in various regions around the globe to analyze dependencies between units Includes modeling techniques of inter-connections and shared resources, as well as risk aggregation
Download or read book Probabilistic Safety Assessment and Management written by Cornelia Spitzer and published by Springer. This book was released on 2014-01-04 with total page 3803 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collection of papers presented at the PSAM 7 – ESREL ’04 conference in June 2004, reflecting a wide variety of disciplines, such as principles and theory of reliability and risk analysis, systems modelling and simulation, consequence assessment, human and organisational factors, structural reliability methods, software reliability and safety, insights and lessons from risk studies and management/decision making. This volume covers both well-established practices and open issues in these fields, identifying areas where maturity has been reached and those where more development is needed.
Download or read book Reliability and Risk Analysis written by Norman J. McCormick and published by Academic Press. This book was released on 1981-07-28 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: A prior knowledge of probability theory would be helpful for the material in Part I; likewise, a previous introduction to the engineered safety features of a nuclear reactor makes portions of Part II easier to understand. For those without this background, introductory material is provided in Chapter 2 and the appendixes.
Download or read book Probabilistic Risk Assessment in the Nuclear Power Industry written by R. R. Fullwood and published by Pergamon. This book was released on 1988 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes a number of the more important improvements in risk assessment methodology in the nuclear industry, developed over the last decade. It presents them in an instructive way so as to be suitable for those wishing to understand the techniques. The methodology of modern probabilistic risk assessment (PRA) is discussed in detail. This book is divided into six parts. Part I, Protecting the Public Health and Safety provides an overview of risk analysis including results presentation, safety goals, emergency planning, and public perception. Part II, the Mathematics, which is necessary to understand the text. Part III, safety Aspects of Light Water Reactors describes the types of plants and goes on to discuss accident initiator selection and frequencies. Part IV, PRA, describes system modelling, human factors analysis, data bases, codes, system interactions, external events, core melt physics, and the transport of radionuclides to the public. Part V discusses 34 types of applications of PRA. Part VI, Resources, provides a glossary, references, and an index. Problems are provided at the end of each part to both stimulate understanding and introduce additional material. This book would be a very valuable addition to the reference library of practitioners in the risk assessment business. It is also a useful instructional text for graduate and undergraduate nuclear engineering students as well as newcomers to the field.
Download or read book NUREG CR written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1977 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Probability High Consequence Risk Analysis written by Ray Waller and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years public attention has focused on an array of low-probability/high-consequence (LC/HC) events that pose a signif icant threat to human health, safety, and the environment. At the same time, public and private sector responsibilities for the assessment and management of such events have grown because of a perceived need to anticipate, prevent, or reduce the risks. In attempting to meet these responsibilities, legislative, judicial, regulatory, and private sector institutions have had to deal with the extraordinarily complex problem of assessing and balancing LP/ HC risks against the costs and ben if its of risk reduction. The need to help society cope with LP/HC events such as nuclear power plant accidents, toxic spills, chemical plant explosions, and transportation accidents has given rise to the development of a new intellectual endeavor: LP/HC risk analysis. The scope and complexity of these analyses require a high degree of cooperative effort on the part of specialists from many f~elds. Analyzing technical, social, and value issues requires the efforts of physicists, biologists, geneticists, statisticians, chemists, engineers, political scientists, sociologists, decision analysts, management scientists, economists, psychologists, ethicists, lawyers, and policy analysts. Included in this volume are papers by authors in each of these disciplines. The papers share in common a focus on one or more of the following questions that are generic to the analysis of LP/HC risks.
Download or read book Nuclear Systems Reliability Engineering and Risk Assessment written by Jerry B. Fussell and published by SIAM. This book was released on 1977-01-01 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Risk Informed Technologies written by Prabhakar V. Varde and published by Springer Nature. This book was released on 2024-01-07 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest research in the areas of development and application of risk-informed and risk-based technologies. The book discusses how advances in computational technologies, availability of accumulated experience and data on design, operations, maintenance and regulations, new insights in human factor modelling and development of new technologies, such as physics-of-failure modelling, prognostics and health management, have paved the way for implementation of risk and reliability tools and methods. The book will be useful for researchers, academicians, and engineers, particularly the field engineers, designers and regulators working on complex engineering systems.
Download or read book Development and Application of Level 1 Probabilistic Safety Assessment for Nuclear Power Plants written by IAEA and published by International Atomic Energy Agency. This book was released on 2024-03-15 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this Safety Guide is to provide recommendations for meeting the requirements of GSR Part 4 (Rev. 1) in the development and application of Level 1 Probabilistic Safety Assessments (PSAs) for nuclear power plants (NPPs). The recommendations provided in this publication promoting technical consistency among Level 1 PSA studies, in order to provide reliable support for applications of PSAs and risk informed decision making, particularly to support the design of NPPs and decision making during plant commissioning and operation. The revised Safety Guide's scope encompasses the main methodological aspects of PSA and in particular has been updated to reflect developments in specific areas, such as passive systems reliability, computer based systems reliability, combinations of hazards, human reliability analysis and to expand the scope of PSA to include site level risk considerations such as multi-unit and spent fuel pool PSA.
Download or read book Human Reliability Analysis in Probabilistic Safety Assessment for Nuclear Power Plants written by International Atomic Energy Agency and published by . This book was released on 1995 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a practical approach for incorporating human reliability analysis (HRA) into probabilistic safety assessment (PSA). This document describes the steps needed and the documentation that should be provided both to support the PSA itself and to ensure effective communication of important information arising from the studies.
Download or read book Conceptual Software Reliability Prediction Models for Nuclear Power Plant Safety Systems written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project is to develop a method to predict the potential reliability of software to be used in a digital system instrumentation and control system. The reliability prediction is to make use of existing measures of software reliability such as those described in IEEE Std 982 and 982.2. This prediction must be of sufficient accuracy to provide a value for uncertainty that could be used in a nuclear power plant probabilistic risk assessment (PRA). For the purposes of the project, reliability was defined to be the probability that the digital system will successfully perform its intended safety function (for the distribution of conditions under which it is expected to respond) upon demand with no unintended functions that might affect system safety. The ultimate objective is to use the identified measures to develop a method for predicting the potential quantitative reliability of a digital system. The reliability prediction models proposed in this report are conceptual in nature. That is, possible prediction techniques are proposed and trial models are built, but in order to become a useful tool for predicting reliability, the models must be tested, modified according to the results, and validated. Using methods outlined by this project, models could be constructed to develop reliability estimates for elements of software systems. This would require careful review and refinement of the models, development of model parameters from actual experience data or expert elicitation, and careful validation. By combining these reliability estimates (generated from the validated models for the constituent parts) in structural software models, the reliability of the software system could then be predicted. Modeling digital system reliability will also require that methods be developed for combining reliability estimates for hardware and software. System structural models must also be developed in order to predict system reliability based upon the reliability of the individual hardware/software components. Existing modeling techniques--such as fault tree analyses or reliability block diagrams--can probably be adapted to bridge the gaps between the reliability of the hardware components, the individual software elements, and the overall digital system. This project builds upon previous work to survey and rank potential measurement methods which could be used to measure software product reliability 3. This survey and ranking identified candidate measures for use in predicting the reliability of digital computer-based control and protection systems for nuclear power plants. Additionally, information gleaned from the study can be used to supplement existing review methods during an assessment of software-based digital systems.
Download or read book Evaluation of Quantification of Margins and Uncertainties Methodology for Assessing and Certifying the Reliability of the Nuclear Stockpile written by National Research Council and published by National Academies Press. This book was released on 2009-03-02 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maintaining the capabilities of the nuclear weapons stockpile and performing the annual assessment for the stockpile's certification involves a wide range of processes, technologies, and expertise. An important and valuable framework helping to link those components is the quantification of margins and uncertainties (QMU) methodology. In this book, the National Research Council evaluates: how the national security labs were using QMU, including any significant differences among the three labs its use in the annual assessment whether the applications of QMU to assess the proposed reliable replacement warhead (RRW) could reduce the likelihood of resuming underground nuclear testing This book presents an assessment of each of these issues and includes findings and recommendations to help guide laboratory and NNSA implementation and development of the QMU framework. It also serves as a guide for congressional oversight of those activities.
Download or read book Probabilistic Risk Assessment written by United States. General Accounting Office and published by . This book was released on 1985 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Digital Instrumentation and Control Systems in Nuclear Power Plants written by Committee on Application of Digital Instrumentation and Control Systems to Nuclear Power Plant Operations and Safety and published by National Academies Press. This book was released on 1997-05-02 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nuclear industry and the U.S. Nuclear Regulatory Commission (USNRC) have been working for several years on the development of an adequate process to guide the replacement of aging analog monitoring and control instrumentation in nuclear power plants with modern digital instrumentation without introducing off-setting safety problems. This book identifies criteria for the USNRC's review and acceptance of digital applications in nuclear power plants. It focuses on eight areas: software quality assurance, common-mode software failure potential, systems aspects of digital instrumentation and control technology, human factors and human-machine interfaces, safety and reliability assessment methods, dedication of commercial off-the-shelf hardware and software, the case-by-case licensing process, and the adequacy of technical infrastructure.
Download or read book Multi state Reliability Analysis of Nuclear Power Plant Systems written by Arun Veeramany and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The probabilistic safety assessment of engineering systems involving high-consequence low-probability events is stochastic in nature due to uncertainties inherent in time to an event. The event could be a failure, repair, maintenance or degradation associated with system ageing. Accurate reliability prediction accounting for these uncertainties is a precursor to considerably good risk assessment model. Stochastic Markov reliability models have been constructed to quantify basic events in a static fault tree analysis as part of the safety assessment process. The models assume that a system transits through various states and that the time spent in a state is statistically random. The system failure probability estimates of these models assuming constant transition rate are extensively utilized in the industry to obtain failure frequency of catastrophic events. An example is core damage frequency in a nuclear power plant where the initiating event is loss of cooling system. However, the assumption of constant state transition rates for analysis of safety critical systems is debatable due to the fact that these rates do not properly account for variability in the time to an event. An ill-consequence of such an assumption is conservative reliability prediction leading to addition of unnecessary redundancies in modified versions of prototype designs, excess spare inventory and an expensive maintenance policy with shorter maintenance intervals. The reason for this discrepancy is that a constant transition rate is always associated with an exponential distribution for the time spent in a state. The subject matter of this thesis is to develop sophisticated mathematical models to improve predictive capabilities that accurately represent reliability of an engineering system. The generalization of the Markov process called the semi-Markov process is a well known stochastic process, yet it is not well explored in the reliability analysis of nuclear power plant systems. The continuous-time, discrete-state semi-Markov process model is a stochastic process model that describes the state transitions through a system of integral equations which can be solved using the trapezoidal rule. The primary objective is to determine the probability of being in each state. This process model ensures that time spent in the states can be represented by a suitable non-exponential distribution thus capturing the variability in the time to event. When exponential distribution is assumed for all the state transitions, the model reduces to the standard Markov model. This thesis illustrates the proposed concepts using basic examples and then develops advanced case studies for nuclear cooling systems, piping systems, digital instrumentation and control (I & C) systems, fire modelling and system maintenance. The first case study on nuclear component cooling water system (NCCW) shows that the proposed technique can be used to solve a fault tree involving redundant repairable components to yield initiating event probability quantifying the loss of cooling system. The time-to-failure of the pump train is assumed to be a Weibull distribution and the resulting system failure probability is validated using a Monte Carlo simulation of the corresponding reliability block diagram. Nuclear piping systems develop flaws, leaks and ruptures due to various underlying damage mechanisms. This thesis presents a general model for evaluating rupture frequencies of such repairable piping systems. The proposed model is able to incorporate the effect of aging related degradation of piping systems. Time dependent rupture frequencies are computed and the influence of inspection intervals on the piping rupture probability is investigated. There is an increasing interest worldwide in the installation of digital instrumentation and control systems in nuclear power plants. The main feedwater valve (MFV) controller system is used for regulating the water level in a steam generator. An existing Markov model in the literature is extended to a semi-Markov model to accurately predict the controller system reliability. The proposed model considers variability in the time to output from the computer to the controller with intrinsic software and mechanical failures. State-of-the-art time-to-flashover fire models used in the nuclear industry are either based on conservative analytical equations or computationally intensive simulation models. The proposed semi-Markov based case study describes an innovative fire growth model that allows prediction of fire development and containment including time to flashover. The model considers variability in time when transiting from one stage of the fire to the other. The proposed model is a reusable framework that can be of importance to product design engineers and fire safety regulators. Operational unavailability is at risk of being over-estimated because of assuming a constant degradation rate in a slowly ageing system. In the last case study, it is justified that variability in time to degradation has a remarkable effect on the choice of an effective maintenance policy. The proposed model is able to accurately predict the optimal maintenance interval assuming a non-exponential time to degradation. Further, the model reduces to a binary state Markov model equivalent to a classic probabilistic risk assessment model if the degradation and maintenance states are eliminated. In summary, variability in time to an event is not properly captured in existing Markov type reliability models though they are stochastic and account for uncertainties. The proposed semi-Markov process models are easy to implement, faster than intensive simulations and accurately model the reliability of engineering systems.
