The Activation Sources of Reactor Internals During Decommissioning

2017 ◽  
Author(s):  
Jianchun Han ◽  
Yan Zhou ◽  
Hui Li ◽  
Qiliang Mei
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Neutron Flux ◽  
Nuclear Power ◽  
Power Plants ◽  
Neutron Transport ◽  
Three Dimensional ◽  
High Energy ◽  
Pressurized Water ◽  
Dimensional Distribution

As China’s first nuclear power plant connected to the grid, the first Qinshan nuclear power plant is approaching the decommissioning period. Other nuclear power plants also turn into the preparation phase of decommissioning in succession. In order to facilitate decommissioning, source survey is conducted during the pre-decommissioning phase, which can provide radioactive inventory, contamination distribution, species and quantities of nuclides. The internals of the reactor work under the most severe radiation environment. During the reactor operation, the materials of internals are irradiated by high-energy neutrons. So activated nuclides are generated due to the neutron capture reaction, which are the main radioactive waste to be treated during decommissioning. In this paper, the neutron irradiation and the generated activation source of the internals for pressurized water reactors (PWR) are studied and analyzed. Firstly, core modeling was carried out, and the neutron transport calculation is performed to obtain three-dimensional distribution of the neutron flux. Secondly, according to the three-dimensional distribution of the material composition and the neutron flux rate of the reactor, the activation calculation is carried out to obtain the activation source.

scholarly journals Validation and Evaluation of COSINE Software Package Based on the Operation Data of Third Generation Passive Pressurized Water Reactor

2021 ◽  
Author(s):  
Weibin Zhang ◽  
Chenglin Zhu ◽  
Qiao Zhang ◽  
Linlin Xu ◽  
Guoping Quan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Software Development ◽  
Nuclear Power ◽  
Power Plants ◽  
Hot Spot ◽  
Third Generation ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor

According to the historical experience of international nuclear power software development and the requirements of relevant guidelines at home and abroad, a large number of experiments and theoretical work must be carried out to verify and confirm the empirical formulas, models and calculation methods used in the software and evaluate the models related to safety evaluation in order to make the software be applied to the design and analysis of nuclear power plants. Validation and evaluation is the most important key link in the process of nuclear power software development, which is heavy workload and difficult, and needs a lot of actual power plant operation data. This paper proposed a research on the validation and evaluation of the COSINE software package’s calculation capability and accuracy based on the operation data of the third generation passive PWR (Pressurized Water Reactor) AP1000. The comparison results between the operation limit parameters of the nuclear power plant including critical boron concentration, heat pipe factor of nuclear enthalpy rise, heat flux hot spot factor and AO (Axial Offset) showed that the data calculated by COSINE met the running requirements of the nuclear power plant, and the calculation accuracy keeps also in a good way.

Aging Evaluation for the Extension of Qualified Life of Nuclear Power Plant Equipment Through Modulated Poisson Processes

2009 ◽  
Author(s):  
Pedro L. C. Saldanha ◽  
P. F. Frutuoso e Melo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Point Processes ◽  
Nuclear Regulatory Commission ◽  
Repairable Systems ◽  
Pressurized Water ◽  
Trade Offs ◽  
Service Water

This paper presents an application of the Modulated Point Process (MPPP) to the service water pumps of a typical pressurized water reactor, as a model for the rate of occurrence of failures (ROCOF) of a repairable system, in order to decide for an extension of the qualified life in the context of a nuclear power plant license renewal. The analysis was carried considering some field data spanning a 2,300 calendar day period, which is approximately equivalent to four burn-up cycles and refueling periods. The reliability is estimated, and maintenance strategies are discussed. As a conclusion, the MPPP is adequate for modeling the rate of occurrence of failures that are time dependent, and can be used where aging mechanisms are present in the operation of repairable systems. This means that equipment characteristics that are important may be inserted into the model and the results can help make decisions in the context of maintenance programs, as is the case with the maintenance rule concept that has been proposed by the Nuclear Regulatory Commission and is about to be implemented in nuclear power plants in Brazil, for instance. Trade-offs on the difficulty with data acquisition for applying point processes are discussed.

Protection of Nuclear Power Plants Against Severe Winds: Impact of the Local Building Configuration on the Wind Speed to Consider

2020 ◽  
Author(s):  
Arièle Défossez ◽  
Eric Dupont ◽  
Laurence Grammosenis ◽  
Hervé Cordier ◽  
Tiphaine Le Morvan
Keyword(s):  
Wind Speed ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Flow Behavior ◽  
Severe Weather ◽  
Wind Rose ◽  
Pressurized Water ◽  
Weather Events

Abstract Over the years, power plants have been hit by numerous severe weather events (storm, flood, heat wave...). EDF (Electricity of France) and ASN (Nuclear Safety Authority) want to assess the future impact of severe weather events on the power plants. Furthermore, recent research on storms estimates more accurate wind speed return values than before. For this reason, the severe wind value is an important parameter to quantify on a NPP (Nuclear Power Plant) site, in order to verify if the protection measures are sufficient or, if necessary, to design adequate protection. To cope with those objectives, wind flow behavior around a PWR (Pressurized Water Reactor) nuclear power plant is studied. The goal of this work is to check that there is no exceeding local wind speed relative to the wind entering the site. The severe winds are characterized locally near the buildings in terms of location and amplitude. Different kind of topology for the nuclear power plant sites are studied in the project: near a cliff, in a plain or in a basin. In our study, the CFD (Computational Fluid Dynamics) open source tool Code_Saturne developed at EDF-R&D is used to simulate the wind over a French PWR site located in nearly flat terrain in a plain. The 3D mesh includes buildings of the site. Several wind directions corresponding to the prevailing winds are studied. Two wind speeds corresponding to wind speed return values are studied (eg: the inlet wind speed is 25 m/s at 10 meter high for a return period of 50 years). Furthermore, several locations selected near buildings are studied carefully. Swirling flows have been viewed between buildings. Analysis of the results shows that the wind speed near the buildings does not exceed the wind speed at the entrance of the domain for the three directions studied except near the cooling towers and above buildings. However, this result should not be generalized to other PWR sites due to the specificities of each site such as relief, buildings position, buildings size, roughness, wind rose... This methodology could be applied at other nuclear power plant sites.

Benchmark Calculations of Pressurizer Model for Maanshan Nuclear Power Plant Using TRACE Code

2008 ◽  
Author(s):  
Yi-Hsiang Cheng ◽  
Chunkuan Shih ◽  
Jong-Rong Wang ◽  
Hao-Tzu Lin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Start Up ◽  
Simulation Results ◽  
Net Load ◽  
Coolant System

Pressurizer plays an important role in controlling the pressure of the primary coolant system in pressurized water reactor (PWR) power plants. An accurate modelling of the pressurizer is needed to determine the pressure histories of the primary coolant system, and thus to successfully simulate overall PWR power plant behavior during transients. The purpose of this study is to develop a pressurizer model, and to assess its pressure transients using the TRACE code version 5.0. The benchmark of the pressurizer model was performed by comparing the simulation results with those from the tests at the Maanshan nuclear power plant. Four start-up tests of the Maanshan nuclear power plant are collected and simulated: 1) turbine trip test from 100% power; 2) large-load reduction at 100% power; 3) net-load trip at 100% power; and 4) net-load trip at 50% power. The simulation results are in reasonable agreement with the start-up tests, and thus the pressurizer model built in this study is successfully verified and validated.

Sensitivity Analysis for Human Errors of a Chemical and Volume Control System at Nuclear Power Plant by Soft Control

2017 ◽  
Author(s):  
Zhang Yuxin ◽  
Yang Kunze
Keyword(s):  
Control System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Sensitivity Analyses ◽  
Volume Control ◽  
Pressurized Water ◽  
Human Errors

The introduction of soft controls into the main control room may provide a more convenient environment for operations, but also may introduce new types of human errors and new risks into the nuclear power plants. In this paper, taking the Chemical and Volume Control System (CVCS) at pressurized water reactor nuclear power plant as an example, the task analysis of operating procedures for starting the CVCS under a normal shut-down operation condition, the potential failure modes during operators executing each step of operating procedures and the dependency analysis of sub-tasks are presented. Furthermore, the sensitivity analyses are conducted for identifying probability importance and critical importance of each model parameter. The countermeasures for preventing and reducing the human errors of soft controls are discussed.

Research on the Computerized Symptom-Oriented Procedures of Nuclear Power Plants

2008 ◽  
Author(s):  
Fei Liu ◽  
Zhijian Zhang ◽  
Minjun Peng
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Interface Design ◽  
Nuclear Power ◽  
Power Plants ◽  
Test Results ◽  
Pressurized Water ◽  
Water Reactors ◽  
Steam Generator Tubes ◽  
Emergency Operating

New methods of information presentation and interface design are changing the working conditions in the modern Nuclear Power Plant (NPP) control room. Symptom-oriented EOPs (SOPs) with their structures and practical application are described. The Computerized Symptom-oriented Operating Procedures (CSOP) is researched, which can help the operator analyze all the symptom signals of steam generator tubes rupture (SGTR) and provide the computerized procedures corresponding to the symptom signals. This paper analyzes the accident of SGTR; the accident management of SGTR is important in reactor safety because SGTR is one of the relatively high-frequency events in pressurized water reactors PWRs. The symptom signals of SGTR and the possible accidents corresponding to the symptom signals are analyzed. The homologous measures of symptoms are summarized. The disposal of SGTR adopts the method of based on symptoms. The programs are developed by VxWorks that is a real-time operating system. The debugging of programs is processed on simulator. The test results indicated that the programs can provide operating procedures according to the symptoms of accidents. After adopting the Computerized Emergency Operating Procedures, the labor intensity and mental burden of operators are lightened. Computerized Emergency Operating Procedures can enhance the reliability, safety and efficiency of Nuclear Power Plant.

Fuzzy multi-objective decision making approach for nuclear power plant installation

2020 ◽  
Vol 39 (5) ◽  
pp. 6339-6350
Author(s):  
Esra Çakır ◽  
Ziya Ulukan
Keyword(s):  
Linear Programming ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Energy Supply ◽  
Energy Demand ◽  
Nuclear Power ◽  
Power Plants ◽  
Total Duration ◽  
Objective Functions ◽  
Multi Objective

Due to the increase in energy demand, many countries suffer from energy poverty because of insufficient and expensive energy supply. Plans to use alternative power like nuclear power for electricity generation are being revived among developing countries. Decisions for installation of power plants need to be based on careful assessment of future energy supply and demand, economic and financial implications and requirements for technology transfer. Since the problem involves many vague parameters, a fuzzy model should be an appropriate approach for dealing with this problem. This study develops a Fuzzy Multi-Objective Linear Programming (FMOLP) model for solving the nuclear power plant installation problem in fuzzy environment. FMOLP approach is recommended for cases where the objective functions are imprecise and can only be stated within a certain threshold level. The proposed model attempts to minimize total duration time, total cost and maximize the total crash time of the installation project. By using FMOLP, the weighted additive technique can also be applied in order to transform the model into Fuzzy Multiple Weighted-Objective Linear Programming (FMWOLP) to control the objective values such that all decision makers target on each criterion can be met. The optimum solution with the achievement level for both of the models (FMOLP and FMWOLP) are compared with each other. FMWOLP results in better performance as the overall degree of satisfaction depends on the weight given to the objective functions. A numerical example demonstrates the feasibility of applying the proposed models to nuclear power plant installation problem.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

scholarly journals Python TensorFlow Big Data Analysis for the Security of Korean Nuclear Power Plants

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1467
Author(s):  
Sangdo Lee ◽  
Jun-Ho Huh ◽  
Yonghoon Kim
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Network Traffic ◽  
Nuclear Power ◽  
Power Plants ◽  
Security Requirements ◽  
Republic Of Korea ◽  
Continuous Data ◽  
Cyber Attack ◽  
The Republic

The Republic of Korea also suffered direct and indirect damages from the Fukushima nuclear accident in Japan and realized the significance of security due to the cyber-threat to the Republic of Korea Hydro and Nuclear Power Co., Ltd. With such matters in mind, this study sought to suggest a measure for improving security in the nuclear power plant. Based on overseas cyber-attack cases and attacking scenario on the control facility of the nuclear power plant, the study designed and proposed a nuclear power plant control network traffic analysis system that satisfies the security requirements and in-depth defense strategy. To enhance the security of the nuclear power plant, the study collected data such as internet provided to the control facilities, network traffic of intranet, and security equipment events and compared and verified them with machine learning analysis. After measuring the accuracy and time, the study proposed the most suitable analysis algorithm for the power plant in order to realize power plant security that facilitates real-time detection and response in the event of a cyber-attack. In this paper, we learned how to apply data for multiple servers and apply various security information as data in the security application using logs, and match with regard to application of character data such as file names. We improved by applying gender, and we converted to continuous data by resetting based on the risk of non-continuous data, and two optimization algorithms were applied to solve the problem of overfitting. Therefore, we think that there will be a contribution in the connection experiment of the data decision part and the optimization algorithm to learn the security data.

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