Use of Reliability Block Diagram and Fault Tree Techniques in Reliability Analysis of Emergency Diesel Generators of Nuclear Power Plants (original) (raw)
Related papers
2020
The power system reliability analysis method is developed from the aspect of reliable delivery of electrical energy to customers. The method is developed based on the fault tree analysis, which is widely applied in the Probabilistic Safety Assessment (PSA). The method is adapted for the power system reliability analysis. The method is developed in a way that only the basic reliability parameters of the analysed power system are necessary as an input for the calculation of reliability indices of the system. The modeling and analysis was performed on an example power system consisting of eight substations. The results include the level of reliability of current power system configuration, the combinations of component failures resulting in a failed power delivery to loads, and the importance factors for components and subsystems.
An Application of the Fault Tree Analysis for the Power System Reliability Estimation
The power system is a complex system with its main function to produce, transfer and provide consumers with electrical energy. Combinations of failures of components in the system can result in a failure of power delivery to certain load points and in some cases in a full blackout of power system. The power system reliability directly affects safe and reliable operation of nuclear power plants because the loss of offsite power is a significant contributor to the core damage frequency in probabilistic safety assessments of nuclear power plants. The method, which is based on the integration of the fault tree analysis with the analysis of the power flows in the power system, was developed and implemented for power system reliability assessment. The main contributors to the power system reliability are identified, both quantitatively and qualitatively.
Assessment of Offsite Power Reliability for Nuclear Power Plants by Fault Tree Analysis
2019
The reliability of offsite power for a nuclear power plant (NPP) isassessed using fault tree (FT) analysis. The method combines alternatingcurrent (AC) load flow analysis with FT technique. The probability of lossof offsite power (LOOP) initiating event is assessed based on theunreliability of the power delivered to the house load of the NPP. Based onthe quantitative and qualitative analysis of the constructed FT, theprobability of the LOOP initiating event is assessed. The FT resultsinclude the importance measures which enable identification of the mostimportant elements of the power system from the aspect of nuclear safety.The impact of changes in the power system to the safety of the NPP isevaluated. The verification of the method was performed on the IEEE testsystem.
Power System Reliability Analysis Using Fault Trees
The power system reliability analysis method is developed from the aspect of reliable delivery of electrical energy to customers. The method is developed based on the fault tree analysis, which is widely applied in the Probabilistic Safety Assessment (PSA). The method is adapted for the power system reliability analysis. The method is developed in a way that only the basic reliability parameters of the analysed power system are necessary as an input for the calculation of reliability indices of the system. The modeling and analysis was performed on an example power system consisting of eight substations. The results include the level of reliability of current power system configuration, the combinations of component failures resulting in a failed power delivery to loads, and the importance factors for components and subsystems.
Event and fault tree model for reliability analysis of the greek research reactor
2013
Fault trees and event trees are widely used in industry to model and to evaluate the reliability of safety systems. Detailed analyzes in nuclear installations require the combination of these two techniques. This work uses the methods of fault tree (FT) and event tree (ET) to perform the Probabilistic Safety Assessment (PSA) in research reactors. The PSA according to IAEA (International Atomic Energy Agency) is divided into Level 1, Level 2 and level 3. At Level 1, conceptually safety systems act to prevent the accident, at Level 2, the accident occurred and seeks to minimize the consequences, known as stage management of the accident, and at Level 3 are determined consequences. This paper focuses on Level 1 studies, and searches through the acquisition of knowledge consolidation of methodologies for future reliability studies. The Greek Research Reactor, GRR - 1, was used as a case example. The LOCA (Loss of Coolant Accident) was chosen as the initiating event and from there were d...
Application of the fault tree analysis for assessment of power system reliability
Reliability Engineering & System Safety, 2009
A new method for power system reliability analysis using the fault tree analysis approach is developed. The method is based on fault trees generated for each load point of the power system. The fault trees are related to disruption of energy delivery from generators to the specific load points. Quantitative evaluation of the fault trees, which represents a standpoint for assessment of reliability of power delivery, enables identification of the most important elements in the power system. The algorithm of the computer code, which facilitates the application of the method, has been applied to the IEEE test system. The power system reliability was assessed and the main contributors to power system reliability have been identified, both qualitatively and quantitatively.
IOP Conference Series: Materials Science and Engineering, 2018
The "fault tree" analysis is one of the most commonly used methods for determining reliability, calculating the probability of failure and thereby determining risk. The primary purpose of this analysis is to evaluate, using analytical and statistical methods, the likelihood of an unfavorable event occurring. These calculations involve the knowledge of system reliability data such as probability of failure, failure rate, time to failure, repair rate etc. Building a "fault tree" model can provide insight into how to pinpoint potential deficiencies within a functional system. In this paper, a defective tree structure was made for the main components of the 060-DA electric diesel locomotive. Five types of equipment part of the locomotive were taken into consideration: mechanical, pneumatic, thermal, power and auxiliary electrical. Each of these contains, in turn, other subassemblies and components. For the latter, some parameters needed to draw the fault tree diagrams were calculated on a statistical basis. In this way, the probability of the locomotive exiting operation was determined as a result of the defects that occurred in the component parts.
Reliability data update method for emergency diesel generator of Daya Bay Nuclear Power Plant
Annals of Nuclear Energy, 2011
In the field of Living Probabilistic Safety Assessment (LPSA) the reliability data updating is an important factor. In risk analysis equipment failure data is needed to estimate the frequencies of events contributing to risk posed by a facility. Five years data of emergency diesel generator (EDG) of Daya Bay Nuclear Power Plant (NPP) has been studied in this paper. The data updating process has been done by using two methods, i.e., the classical method and Bayesian method. The aim of using these methods is to calculate the operational failure rate (k) and demand failure probability (p). The results show that the operational failure rate is 1.7EÀ3 per hour and the demand failure probability is 2.4EÀ2 demand per day for Daya Bay NPP. By comparing the results obtain from classical and Bayesian methods with EDF (Electric De France) it is concluded that the design and construction of Daya Bay NPP is very different than EDF therefore the reliability parameters used in Daya Bay NPP is based on the classical method.
Fault tree and reliability analysis
1977
Originally presented as the first author's thesis, (Sc. D.)--in the M.I.T. Dept. of Nuclear Engineering, 1977Includes bibliographical references (p. 311-312