Nuclear Reactor Pressure Vessel Integrity Assessment: Enhancement Provided by 3D Modeling Flaw Stability Calculations

2013 ◽  
Author(s):  
Adolfo Arrieta-Ruiz ◽  
Eric Meister ◽  
Henriette Churier
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Integrity Assessment ◽  
Potential Damage ◽  
Vessel Integrity ◽  
Reactor Pressure

Structural integrity of the Reactor Pressure Vessel (RPV) is one of the main considerations regarding safety and lifetime of Nuclear Power Plants (NPP) since this component is considered as not reasonably replaceable. Brittle fracture risk associated with the embrittlement of RPV steel in irradiated areas is the main potential damage. In France, deterministic integrity assessment for RPV is based on the crack initiation stage. The stability of an under-clad postulated flaw in the core area is currently evaluated under a Pressurized Thermal Shock (PTS) through a fracture mechanics simplified method. One of the axes of EDF’s implemented strategy for NPP lifetime extension is the improvement of the deterministic approach with regards to the input data and methods so as to reduce conservatisms. In this context, 3D finite element elastic-plastic calculations with flaw modelling have been carried out recently in order to quantify the enhancement provided by a more realistic approach in the most severe events. The aim of this paper is to present both simplified and 3D modelling flaw stability evaluation methods and the results obtained by running a small break LOCA event.

Assessment of the Reactor Pressure Vessel Integrity in PTS Conditions: Presentation and Demonstration of SECURE — A Numerical Tool Developed by EDF to Realise Automatically Integrity Assessments

2008 ◽  
Author(s):  
A. Dahl ◽  
C. Messelier-Gouze
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Reactor Pressure Vessel ◽  
Full Data ◽  
Integrity Assessment ◽  
Nuclear Plants ◽  
Numerical Tool ◽  
Vessel Integrity ◽  
Reactor Pressure

The reactor pressure vessel (RPV) is an essential component liable to limit the lifetime duration of PWR nuclear power plants. For the RPV assessment and Lifetime evaluation of the nuclear plants, French Utility applies a series of calculations including different approaches, more or less refined. These approaches combine different types of data : neutron physics, vessel geometry, material data, thermal and mechanical transients. SECURE, a numerical tool based on EDF finite element code, code_Aster, and full data bases was developed by EDF in order to make automatically RPV integrity assessment with simplified approaches (1D computations) and more refined approaches (2D and 3D computations). Then, with this tool, RPV integrity studies are made more quickly and with more reliability. This paper describes SECURE tool and presents an application with more and less refined methods on a 3D thermal computation of a transient. This application shows that this tool allowed to do easily refined numerical methods which improve the final margins. This tool, developed and validate by EDF Research and development division, must now be used by engineering division.

Upgrading the Operational Safety of Nuclear Power Plants Through the TACIS Nuclear Safety Assistance Programme

2004 ◽  
Author(s):  
M. Bie`th ◽  
R. Ahlstrand ◽  
C. Rieg ◽  
P. Trampus
Keyword(s):  
European Commission ◽  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Nuclear Safety ◽  
Reactor Pressure Vessel ◽  
Nuclear Safeguards ◽  
Integrity Assessment ◽  
Reactor Pressure

The European Union’ TACIS programme was established for the New Independent States since 1991. One priority for TACIS funding is nuclear safety. The European Commission has made available a total of € 944 million for nuclear safety programmes covering the period 1991–2003. The TACIS nuclear safety programme is devoted to the improvement of the safety of Soviet designed nuclear installations in providing technology and safety culture transfer. The Joint Research Center (JRC) of the European Commission is carrying out works in the following areas: • On-Site Assistance for TACIS Nuclear Power Plants; • Design Safety and Dissemination of TACIS results; • Reactor Pressure Vessel Embrittlement for VVER in Russia and Ukraine; • Regulatory Assistance; • Industrial Waste Management and Nuclear Safeguards. This paper gives an overview of the Scientific and Technical support that JRC is providing for the programming and the implementation of the TACIS nuclear safety programmes. In particular, two new projects are being implemented to get an extensive understanding of the VVER reactor pressure vessel embritttlement and integrity assessment.

Using a Probabilistic Approach in the Brittle Fracture Deterministic Integrity Assessment of a Nuclear Reactor Pressure Vessel

2011 ◽  
Author(s):  
Romain Beaufils ◽  
Eric Meister ◽  
Emmanuel Ardillon
Keyword(s):  
Brittle Fracture ◽  
Pressure Vessel ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Probabilistic Method ◽  
Probabilistic Approach ◽  
Reactor Pressure Vessel ◽  
Deterministic Method ◽  
Integrity Assessment ◽  
Reactor Pressure

This work deals with the possibility of the life extension of nuclear power plants in France. The aim is to justify the resistance of the pressure vessel, which is non-replaceable. The brittle fracture deterministic integrity assessment of the nuclear Reactor Pressure Vessel (RPV) is based on the analysis of a flaw under the austenitic cladding of the RPV. The demonstration of the RPV resistance is controlled by the regulations. It is proposed here to use a probabilistic method by propagating uncertainties into the deterministic mechanical model in order to quantify conservatism of the deterministic method. The regulatory requirements must be respected and the purpose of the work presented here is thus to link the probabilistic result to the deterministic method.

Ways for Extending the Reactor Pressure Vessel Lifetime

2008 ◽  
Author(s):  
Milan Brumovsky
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Integrity Assessment ◽  
Low Leakage ◽  
Vessel Integrity ◽  
Direct Use ◽  
Reactor Pressure ◽  
Lifetime Extension

Reactor pressure vessels are components that usually determine the lifetime of the whole nuclear power plant and thus also its efficiency and economy. There are several ways how to ensure conditions for reactor pressure vessel lifetime extension, mainly: - pre-operational, like: • optimal design of the vessel; • proper choice of vessel materials and manufacturing technology; - operational, like: • application of low-leakage core; • increase of water temperature in ECCS; • insertion of dummy elements; • vessel annealing; • decrease of conservatism during reactor pressure vessel integrity assessment e.g. using direct use of fracture mechanics parameters, like “Master Curve” approach. All these ways are discussed in the paper and some qualitative as well as quantitative evaluation is given.

The Delivery of Technical Training Within the European Style Project

2013 ◽  
Author(s):  
Adam Toft ◽  
John Sharples
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Nuclear Industry ◽  
Technical Training ◽  
Illustrative Case ◽  
Integrity Assessment ◽  
Leak Before Break ◽  
Reactor Pressure

The STYLE project considers structural integrity for lifetime management of non-reactor pressure vessel components of nuclear power plant. The project is funded under the seventh European Commission framework programme. A broad objective of the project is to assess, optimise and develop application of advanced tools for structural integrity assessment of reactor coolant pressure boundary components other than the reactor pressure vessel. One aspect of the STYLE project is intended to address the issue of succession planning within the European nuclear industry. With many key technical experts now approaching retirement it is essential to progress the technical expertise of those at an earlier stage of their career in the industry. The paper describes how technical training has been delivered as an integral part of the STYLE project to support retention of the current level of technical capability in future. Diverse aspects of training are described. These include participation in experimental work, numerical modelling and simulation, application of engineering assessment procedures, leak-before-break, probabilistic fracture mechanics and materials behaviour. An illustrative case study is described, in which trainees received practical instruction in the essential steps for technical justification of a leak-before-break argument.

The Importance of a Strong Training Element Within the European STYLE Project

2012 ◽  
Author(s):  
Adam Toft ◽  
John Sharples
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Nuclear Industry ◽  
Framework Programme ◽  
Integrity Assessment ◽  
Future Viability ◽  
European Nuclear ◽  
Reactor Pressure

With many key technical experts within the European nuclear industry now approaching retirement, the continued training and professional development of less experienced people is vital for the future viability of the industry. Consequently, European framework programme projects are including a strong training element within their work packages. The STYLE project considers structural integrity for lifetime management of non-reactor pressure vessel components of nuclear power plant. The project is funded under the seventh European Commission framework programme. The objective of the project is to assess, optimise and develop application of advanced tools for structural integrity assessment of reactor coolant pressure boundary components other than the reactor pressure vessel.

scholarly journals ANALYSIS OF 3D SEMI-ELLIPTICAL CRACK ON REACTOR PRESSURE VESSEL WALL WITH LOAD STRESS AND CRACK RATIO

2019 ◽  
Vol 21 (1) ◽  
pp. 33
Author(s):  
Mike Susmikanti ◽  
Roziq Himawan ◽  
Entin Hartini ◽  
Rokhmadi Rokhmadi
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Goodness Of Fit ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Elliptic Crack ◽  
J Integral ◽  
Integrity Assessment ◽  
Neutron Exposure ◽  
Reactor Pressure

Reactor Pressure Vessel (RPV) wall is an important component in the Nuclear Power Plant (NPP). During reactor operation, RPV is subjected to high temperature, pressure, and neutron exposure. This condition could lead to RPV structure failure. In order to assure the integrity of RPV during the reactor lifetime, it is mandatory to perform a structural integrity assessment of RPV by evaluating postulated crack in RPV. In the previous study, the crack has evaluated in 2-D. However, 3-D analysis of semi-elliptic crack shape in the surface of the thick plate for RPV wall using SA 508 Steel is yet to be analyzed. The objective of this study is to analyze and modeling the evaluation in variation crack ratio with some load stress in 3-D. The Stress Intensity Factor (SIF) and J-integral are used as crack parameter. The J-Integral were calculated using MSC MARC MENTAT based on Finite Element Method (FEM) for obtaining the SIF value. The inputs are a crack ratio, load stress, material property, and geometry. The modeling of SIF value and goodness of fit are using MINITAB. The fracture condition could be predicted in comparison to the SIF value and fracture toughness. For the load stress 70 MPa and 80 MPa, with a crack ratio 0.25, 0.33 and 0.5,  the material on RPV wall will in fracture condition.Keywords: Semi elliptic surface crack, 3-dimension, reactor pressure vessel, elastic-plastic fracture mechanics, J-integral

scholarly journals Evaluation of VVER-1200/V-491 Reactor Pressure Vessel integrity during large break LOCA along with SBO using MELCOR 1.8.6

2015 ◽  
Vol 5 (4) ◽  
pp. 54-63
Author(s):  
Thi Hoa Bui ◽  
Chi Thanh Tran
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Reactor Pressure Vessel ◽  
Severe Accident ◽  
Worst Case ◽  
Safety Requirements ◽  
Vessel Integrity ◽  
Reactor Pressure

After Fukushima accident and stress test recommended by IAEA for existing reactors, higher safety requirements are enforced upon nuclear power plants during design extension and severe accident conditions. Based on those arguments, Vietnam Government requests a lot of effective safety solutions, in designs proposed for the nuclear power plants in Ninh Thuan province of Vietnam, which can prevent the accident progression toward severe accidents and mitigate severe accident consequences. One of safety requirements is related to delay time of core melt during design extension condition. Especially, if the worst case of accidents occurs, the reactor vessel integrity must be maintained at least 24 hours from the beginning of the accident. With the aim at investigation of Reactor Pressure Vessel (RPV) integrity, in this study, MELCOR 1.8.6 code is used to evaluate the integrity of RPV lower head for VVER-1200/V-491 reactor during a Large Break Loss of Coolant Accident (LBLOCA) in combination with Station Blackout (SBO) event. The study figures out several parameters related to melt down progress such as: rupture position and rupture timing, the amount of hydrogen generated. Availability of the second stage hydro-accumulators (HA2) in the VVER-1200/V-491 is assumed as an additional improvement to delay the timing of core melt as well as to maintain the vessel integrity for long-term.

Achievements of the European Style Project Technical Training Programme

2014 ◽  
Author(s):  
Adam Toft ◽  
John Sharples
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Training Programme ◽  
Reactor Pressure Vessel ◽  
Nuclear Industry ◽  
Integrity Assessment ◽  
European Nuclear ◽  
Broad Objective ◽  
Reactor Pressure

The STYLE project considers structural integrity for lifetime management of non-reactor pressure vessel components of nuclear power plant. The project is funded under the seventh European Commission framework programme. A broad objective of the project is to assess, optimise and develop application of advanced tools for structural integrity assessment of reactor coolant pressure boundary components other than the reactor pressure vessel. One aspect of the STYLE project is intended to address the issue of succession planning within the European nuclear industry. With many key technical experts now approaching retirement it is essential to progress the technical expertise of those at an earlier stage of their career in the industry.

Chinese Innovative Patent Technologies for the Reactor Pressure Vessel

2014 ◽  
Author(s):  
Qian Shi ◽  
Tianqi Zhang ◽  
Xiang Fang ◽  
Wei Peng
Keyword(s):  
Pressure Vessel ◽  
Nuclear Power ◽  
High Performance ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Reactor Pressure Vessel ◽  
Operating Pressure ◽  
Energy And Environment ◽  
Airtight Container ◽  
Reactor Pressure

There is a huge and rapid growing demand for energy in China. The developing of new energy, including nuclear energy, is an important way to solve China’s energy and environment problems. Currently, Nuclear power is playing a more and more important role in China, especially in the coastal areas where the economy is developing rapidly. The main nuclear reactor equipment is the key guarantee to nuclear safety, such as the reactor pressure vessel. With the continuous development of science and technology, the reactor pressure vessel uses more and more of advanced design methods, high performance materials and industrial-proven technologies. As an airtight container who is directly exposed to the great operating pressure of reactor, the reactor pressure vessel plays a crucial role to the safety of reactor. In the paper, by retrieving Chinese Intellectual Property Office patent libraries, 12 Chinese innovative patents for the reactor pressure vessel are introduced, containing four kinds of main technologies: closure, body, nozzle safe end and other technologies. The patent results could lead the corresponding advice to the design of the equipment effectively, to the system arrangement reasonably, and further to the reference for designing a safe nuclear power plants. The paper is to exchange the latest technological progress of reactor pressure vessel, in order to promote technological innovation in the nuclear power field.

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