scholarly journals European Project ATLAS+: Small and Large Scale Ductile Tearing Experiments on Ferritic Steel WB36 to Study Transferability of Material Ductile Properties

2019 ◽  
Author(s):  
Anna Dahl ◽  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Willy Vincent
Keyword(s):  
Ferritic Steel ◽  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Test Facility ◽  
Small Scale ◽  
Feed Water ◽  
Ductile Tearing ◽  
Integrity Assessment ◽  
European Project

Abstract The 4-years European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) has been launched in June 2017. One of its objectives is to study the transferability of material ductile properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment. The study of properties transferability is based on a wide experimental programme which includes a full set of fracture experiments conducted on conventional fracture specimens and large scale components (mainly pipes). Three materials are considered in the programme : a ferritic steel WB36 typical from secondary feed water line in German PWR reactors, an aged stainless steel austenitic weld representative of EPR design and a typical VVER austenitic dissimilar weld (DMW). This paper describes the experimental work conducted on the ferritic steel WB 36 (15NiCuMoNb5) and summarizes the experimental results available after 2 years of work. Numerous mechanical tests have been conducted on a wide panel of fracture mechanics specimens for a full characterization of the ferritic steel: Tensile properties, Hardness, Charpy Energy, pre-cracked Charpy PCC, Master curve on CT and SENT specimens, ductile tearing properties on CT and SENT specimens. In parallel, it is planned to test three 4PB large scale tests on pipings (FP1, FP2 and FP3) at room temperature on the EDF test facility with 3 configurations (shape, size and location) of cracks: through wall crack (TWC), internal and external ½ elliptical cracks. Progress of these large scale experiments is described including first results.

European Project ATLAS+: Status of the WP1 Relative to the Experimental Program on Pipes and Specimens

2020 ◽  
Author(s):  
Dominique Moinereau ◽  
Tomas Nicak ◽  
Anna Dahl
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Ductile Material ◽  
Experimental Program ◽  
Small Scale ◽  
Integrity Assessment ◽  
European Project

Abstract The 4-year European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) was launched in June 2017. One of its objectives is to study the transferability of ductile material properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment. The study of properties transferability is based on a wide experimental program — within the framework of work-package 1 (WP 1) — which includes a full set of fracture experiments conducted on conventional fracture specimens and on large scale components (mainly pipes). Three materials are considered in the program: a low-alloy ferritic steel 15NiCuMoNb5 (WB36) typical from feedwater line in German PWR, an aged austenitic stainless steel weld typical (narrow gap) from EPR and a typical VVER austenitic stainless steel dissimilar weld (DMW). Several European organizations are involved in the experimental work: EDF, CEA, Framatome, ARMINES, KIWA, Framatome GmbH, VTT, BZN, MTA-EK, and CIEMAT.

Advanced Structural Integrity Assessment Tools for Safe Long Term Operation: ATLAS+ Project — Status of the Activities of the WP3 on Modelling

2019 ◽  
Author(s):  
Stéphane Marie ◽  
Arnaud Blouin ◽  
Tomas Nicak ◽  
Dominique Moinereau ◽  
Anna Dahl ◽  
...  
Keyword(s):  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Local Approach ◽  
Coupled Models ◽  
Large Defect ◽  
Ductile Tearing ◽  
Term Operation ◽  
Integrity Assessment

Abstract The main objective and mission of the ATLAS+ project is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. ATLAS+ WP3 focuses mainly on ductile tearing prediction for large defect in components: Several approaches have been developed to accurately model the ductile tearing process and to take into account phenomena such as the triaxiality effect, or the ability to predict large tearing in industrial components. These advanced models include local approach coupled models or advanced energetic approaches. Unfortunately, the application of these tools is today rather limited to R&D expertise. However, because of the continuous progress in the performance of the calculation tools and accumulated knowledge, in particular by members of ATLAS+, these models can now be considered as relevant for application in the context of engineering assessments. WP3 will therefore: • Illustrate the implementation of these models for industrial applications through the interpretation of large scale mock-ups (with cracks in weld joints for some of them), • Make recommendations for the implementation of the advanced models in engineering assessments, • Correct data from the conventional engineering approach by developing a methodology to produce J-Δa curve suitable case by case, based on local approach models, • Improve the tools, guidance and procedures for undertaking leak-before-break (LBB) assessments of piping components, particularly in relation to representing structural representative fracture toughness J-Resistance curves and the influence of weld residual stresses. To achieve these goals, WP3 is divided into 4 sub-WPs and this paper presents the progress of the work performed in each sub-WP after 24 months of activities.

The Experimental Work in Support to ATLAS+ Project

2018 ◽  
Author(s):  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Anna Dahl ◽  
Yann Kayser ◽  
Szabolcs Szavai ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Experimental Work ◽  
Large Scale ◽  
Nuclear Reactor ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Ductile Material ◽  
Small Scale ◽  
Term Operation ◽  
Integrity Assessment

The 4-years European project ATLAS+ project was launched in June 2017. Its main objective is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. The transferability of ductile material properties from small scale fracture mechanics specimens to large scale components is one of the topics of the project. A large programme of experimental work is to be conducted in support of the development and validation of advanced tools for structural integrity assessment within the framework of the work-package 1 (WP 1): Design and execution of simulation oriented experiments to validate models at different scales. The experimental work is based on a full set of fracture mechanics experiments conducted on standard specimens and large scale components (several pipes and one mock-up), including a full materials characterization. Three materials are considered: • a ferritic steel 15NiCuMoNb5 (WB 36) • an aged austenitic stainless steel weld • a VVER (eastern PWR) dissimilar metal weld (DMW) The paper presents the WP 1, the experimental programme and summarizes the first results.

Advanced Structural Integrity Assessment Tools for Safe Long Term Operation: ATLAS+ Project — Status of the Activities of the WP3 on Modelling in 2020

2020 ◽  
Author(s):  
Arnaud Blouin ◽  
Stéphane Marie ◽  
Tomas Nicak ◽  
Antti Timperi ◽  
Peter Gill
Keyword(s):  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Local Approach ◽  
Coupled Models ◽  
Large Defect ◽  
Ductile Tearing ◽  
Term Operation ◽  
Integrity Assessment

Abstract The main objective and mission of the ATLAS+ project is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. ATLAS+ WP3 focuses mainly on ductile tearing prediction for large defect in piping and associated components: Several approaches have been developed to accurately model the ductile tearing process and to take into account phenomena such as triaxiality effects, or the ability to predict large tearing in industrial components. These advanced models include local approach coupled models or advanced energetic approaches. Unfortunately, the application of these tools is currently rather limited to R&D expertise. However, because of the continuous progress in the performance of calculation tools and accumulated knowledge, in particular by members of the ATLAS+ consortium, these models can now be considered as relevant for application in the context of engineering assessments. WP3 has been planned to: • Illustrate the implementation of these models for industrial applications through the interpretation of large scale mock-ups (with cracks in weld joints for some of them), • Make recommendations for the implementation of the advanced models in engineering assessments, • Correct data from the conventional engineering approach by developing a methodology to produce J-Δa curve suitable case by case, based on local approach models, • Improve the tools, guidance and procedures for undertaking leak-before-break (LBB) assessments of piping components, particularly in relation to representing structural representative fracture toughness J-Resistance curves and the influence of weld residual stresses. To achieve these goals, WP3 is divided into 4 sub-WPs and this paper presents the progress of the work performed in each sub-WP after 36 months of activities.

European Project ATLAS+: Status of the WP1 Relative to the Experimental Program on Pipes and Specimens

2019 ◽  
Author(s):  
Patrick Le Delliou ◽  
Dominique Moinereau ◽  
Myriam Bourgeois ◽  
Szabolcs Szavai
Keyword(s):  
Fracture Mechanics ◽  
Experimental Work ◽  
Ferritic Steel ◽  
Large Scale ◽  
Assessment Tools ◽  
Ductile Material ◽  
Experimental Program ◽  
Small Scale ◽  
European Project ◽  
Experimental Programme

Abstract The 4-year European project ATLAS+ project was launched in June 2017. Its main objective is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. The transferability of ductile material properties from small scale fracture mechanics specimens to large scale components is one of the topics of the project. A large experimental work is conducted in support to development and validation of advanced tools for structural integrity assessment within the framework of the work-package 1 (WP 1): Design and execution of simulation oriented experiments to validate models at different scales. The experimental work is based on a full set of fracture mechanics experiments conducted on specimens and large scale components (several pipes and one mock-up), including a full materials characterization. Three materials are considered: • a ferritic steel 15NiCuMoNb5 (WB 36) • an aged austenitic stainless steel weld • a VVER dissimilar metal weld (DMW) This paper presents the WP 1, the experimental programme and summarizes the first results. A companion paper [1] presents in more details the experimental programme on the ferritic steel.

STYLE Project: A Large Scale Ductile Tearing Experiment on a Cladded Ferritic Pipe

2014 ◽  
Author(s):  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Elisabeth Keim ◽  
Tomas Nicak
Keyword(s):  
Crack Growth ◽  
Base Metal ◽  
Ferritic Steel ◽  
Large Scale ◽  
Bending Test ◽  
Test Facility ◽  
Outer Diameter ◽  
Ductile Tearing ◽  
Wide Range ◽  
Scale Experiment

Within the framework of the FP7 European project STYLE, a large scale experiment has been performed at EDF on a cladded ferritic pipe. The objective of such an experiment was to investigate transferability of material properties from small specimens to large scale components. The large scale experiment involves applying 4-point bending under displacement control at room temperature to a clad ferritic steel pipe with an internal surface crack. The goal of the experiment is to initiate ductile crack growth and track the resulting stable crack growth until the surface flaw fails by producing a through-wall crack. The test specimen is representative from a surge line consisting of a clad ferritic pipe with an outer diameter of 420 mm, length of 520 mm, and base metal wall thickness of 31 mm, with an internal austenitic stainless steel cladding layer of thickness 5 mm. The base metal is a low alloy 20MnMoNi55 steel (corresponding to the specifications of an SA 508 Grade 3, Class 1 steel), and the necessary extensions are made of a high strength ferritic steel. A wide range of instrumentation was implemented to provide data for mock-up behavior understanding and detect the ductile tearing initiation during the test. The test has been conducted with full success on the EDF 4 point bending test facility. After the experiment, samples have been taken from the mock-up for full SEM fractographic examinations of the fracture surface for identification of failure modes. The present paper describes the large scale experiment and presents the main experimental results and data. A synthesis of SEM fractographic examinations is also presented, to better understand the rupture behavior during the test.

Project STYLE: Post-Test Analysis of Mock-Up3

2014 ◽  
Author(s):  
Tomas Nicak ◽  
Herbert Schendzielorz ◽  
Elisabeth Keim ◽  
Gottfried Meier ◽  
Dominique Moinereau ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Large Scale ◽  
Structural Integrity ◽  
Small Scale ◽  
Primary Circuit ◽  
Term Operation ◽  
Integrity Assessment ◽  
Work Related ◽  
Post Test ◽  
Circuit Components

The safety and reliability of all systems has to be maintained throughout the lifetime of a nuclear power plant. Continuous R&D work is needed in targeted areas to meet the challenges of long term operation of existing and new plants designs. The European project STYLE aims to develop and validate advanced methods of structural integrity assessment applicable in the ageing and lifetime management of primary circuit components. There are three large scale mock-up tests in STYLE each of them dedicated to investigate specific effects. This paper presents the work related to Mock-up3, which is dedicated to investigate influence of cladding on the crack initiation and propagation as well as the transferability of material properties from small scale specimens to a large scale component. The performed post-test analyses focus on both the further understanding and interpretation of the Mock-up3 test and on the effect of cladding on structural integrity and LBB behavior of reactor coolant pressure boundary components.

Ductile Tearing Prediction of Ferritic Pipe Material by GTN Model for ATLAS+ European Project

2020 ◽  
Author(s):  
Kiminobu Hojo ◽  
Takatoshi Hirota ◽  
Naoki Ogawa ◽  
Satoshi Kumagai
Keyword(s):  
Fracture Behavior ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Pipe Material ◽  
Work Package ◽  
Gtn Model ◽  
Term Operation ◽  
Integrity Assessment ◽  
European Project

Abstract The main objective and mission of the European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe Long Term Operation) are to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. This project includes the development and validation of advanced simulation tools based on fracture mechanics methods using physically based mechanistic models. In the Work Package 3 (WP3), benchmark calculations using different available models are conducted to investigate the accuracy and the capability of the different models for ductile crack growth of different constraint condition, such as laboratory specimens and piping structure, which were tested in the Work Package 1 (WP 1). The authors joined the WP3 activity and investigated the effect of the parameters of the GTN (Gurson-Tvergaard-Needleman) model on the fracture behavior of the specimens. In this paper, the parameters of the GTN model were calibrated to simulate the fracture behavior of CT specimens, notched tensile (NT) specimens and single edge notched tensile (SENT) specimens of ferritic pipe material and the applicability of the GTN model. The adjusted parameters by the CT specimen predicted the fracture behavior of the SENT specimens, but did not those of the NT specimens. The adjusted parameters by the CT specimens were applied to the piping structure mock-up and they predicted the maximum load in high accuracy.

Four Points Bending Test on an EPR Type DMW Pipe Containing a Through-Wall Defect: Experimental and Numerical Analysis From Small Specimens Until Pipe Scale

2014 ◽  
Author(s):  
M. Bourgeois ◽  
S. Chapuliot ◽  
S. Marie ◽  
O. Ancelet ◽  
Y. Kayser
Keyword(s):  
Numerical Analysis ◽  
Ferritic Steel ◽  
Large Scale ◽  
Bending Test ◽  
Small Scale ◽  
Narrow Gap ◽  
Fracture Test ◽  
Ductile Tearing ◽  
Four Point Bending ◽  
Four Point Bending Test

Within the framework of European project STYLE [1], a fracture test on a pipe containing a through wall crack in a narrow gap Inconel Dissimilar Metals weld (welds named hereafter DMW) has been performed. The work is focusing on the Inconel - ferritic steel interface which is the weakest area of such welded pipes in front of ductile tearing. The study temperature is 300°C, which covers typical temperatures in components like hot pipes in the primary coolant system of pressurized water reactors. The four point bending test was carried out by the French Atomic Energy Commission and Alternative Energies (CEA), in order to study the mechanical properties and integrity of component such as the DMW pipes provided and designed by AREVA France. The observations made post-mortem showed a small 2.5 mm ductile tearing at the interface of Inconel and ferritic steel, and after this point, a large crack that has deviated from the interface to propagate in the Inconel and then in the stainless steel. The DMW Mock-up is presented with previous results concerning the mechanical characterizations of his constitutive materials. The second part of this paper is devoted to the four point bending test at 300°C: procedure, instrumentation and interpretation of large-scale test in terms of initiation and propagation of cracks. A comparison is made with tests performed at a smaller scale on multi-material CT specimens. The third part deals with first numerical analysis of fracture test. The results are interpreted on a small scale using finite element analysis to obtain the parameters of damage models that are needed for global approach. Finally, numerical approaches is presented and applied to simulate the fracture of the large-scale pipe. The aim of this paper is to propose and discuss the validity of new assessment methods of ductile propagation in a large scale pipe containing a through wall crack in a narrow gap dissimilar metal weld.

STYLE: Project Overview

2010 ◽  
Author(s):  
Tomas Nicak ◽  
Elisabeth Keim
Keyword(s):  
Time Management ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Best Practice ◽  
Structural Integrity ◽  
Life Time ◽  
Assessment Tools ◽  
Integrity Assessment ◽  
University Of Bristol

The purpose of this paper is to introduce a new EUROATOM project focusing on the structural integrity assessment of reactor coolant pressure boundary components (RCPB) relevant to ageing and life time management. The project started in January 2010 and will last 4 years. The project is coordinated by AREVA NP GmbH with 20 partner organizations from Europe, one collaborator from USA and one collaborator from Russia: AEKI, Hungary; AREVA NP GmbH, Germany (coordination, WP2 leader); AREVA NP SAS, France; Bay Zoltan, Hungary; British Energy Generation Ltd., UK (WP7 leader); CEA, France (WP1 leader); EDF, France; IdS, France; INR, Romania; IWM, Germany; JRC, Netherlands (WP4 leader); NRI, Czech Republik; NRG, Netherlands; SCK-CEN, Belgium; Serco Assurance Technical Services, UK (WP3 and WP5 leader); University of Bristol, UK; University of Manchester, UK; Technatom, Spain; Vattenfall, Sweden (WP6 leader); VTT, Finland. Within STYLE (Structural integrity for lifetime management – non-RPV components) realistic failure models for some of the key components will be identified. The range of assessment tools considered will include those for assessment of component failure by advanced fracture mechanics analyses validated on small and large scale experiments, quantification of weld residual stresses by numerical analysis and by measurements, stress corrosion crack initiation/ growth effects and assessment of RCPB components (excluding the reactor pressure vessel) under dynamic and seismic loading. Based on theoretical and experimental results, performance assessment and further development of simplified engineering assessment methods (EAM) will be carried out considering both deterministic and probabilistic approaches. Integrity assessment case studies and large scale demonstration experiments will be performed on Mock-ups of safety-relevant components. These will include a repair weld in an aged butt-welded austenitic pipe, a dissimilar narrow gap TIG weld (following the EPR design) and a cladded ferritic pipe. Moreover experiments on specimens and feature test pieces will be carried out to support the large scale Mock-up analyses. The end product of the project (“STYLE TOOLS”) will comprise best practice guidelines on the use of advanced tools, on improvement and qualification of EAM as a part of European Leak-before-break (LBB) procedures and on life time management of the integrity of RCPB components in European nuclear power plants. The project will interact with the European Network of Excellence NULIFE.

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