INCEFA-PLUS: Increasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment

2020 ◽  
Author(s):  
Kevin Mottershead ◽  
Matthias Bruchhausen ◽  
Sergio Cicero ◽  
Sam Cuvilliez
Keyword(s):  
Strain Amplitude ◽  
Surface Finish ◽  
Nuclear Power ◽  
Power Plants ◽  
Hold Time ◽  
Austenitic Stainless Steels ◽  
Common Interest ◽  
The Status ◽  
Assessment Guidelines ◽  
Mean Strain

Abstract INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 programme. The project concludes in June 2020. 16 organisations from across Europe have combined forces to deliver new experimental data which is being used to develop improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain and stress, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments have been studied experimentally, these being issues of common interest to all participants. The data obtained has been collected and standardised in an online environmental fatigue database, implemented with the assistance of an INCEFA-PLUS led CEN workshop on this aspect. As the end of the project approaches, INCEFA-PLUS is developing and disseminating methods for including the new data into assessment approaches for environmental fatigue degradation. This paper provides an overall update to project developments since it was last presented at PVP2019 (PVP2019-93276), and provides provisional project conclusions (which will be finalised for presentation at the conference). As well as being a standalone paper, the paper will also serve as an introduction to other papers being submitted covering specific aspects of the project. In particular this paper summarises: • The results of 3 years of testing (nearly concluded at the time of paper submission) • A summary of revealed sensitivities to, and inter-dependencies between: ○ Mean strain and stress, surface finish, strain amplitude and hold time. ○ Environment ○ Material ○ Laboratory (including specimen size and form) • The latest thoughts on how the project results will be used to advance development of improved assessment guidelines. • Progress developing an International EAF database. • A summary of dissemination achieved and planned. • The status of INCEFA-SCALE plans for work after the end of INCEFA-PLUS.

INCEFA-PLUS: Increasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment

2019 ◽  
Author(s):  
Kevin Mottershead ◽  
Matthias Bruchhausen ◽  
Sergio Cicero ◽  
Sam Cuvilliez
Keyword(s):  
Strain Amplitude ◽  
Surface Finish ◽  
Nuclear Power ◽  
Power Plants ◽  
Hold Time ◽  
Austenitic Stainless Steels ◽  
Companion Paper ◽  
Common Interest ◽  
Assessment Guidelines ◽  
Mean Strain

Abstract INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 programme. The project commenced in mid-2015. Sixteen organisations from across Europe have combined forces to deliver new experimental data which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain and stress, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments are being studied experimentally, these being issues of common interest to all participants. The data obtained is being collected and standardised in an online environmental fatigue database, implemented with the assistance of an INCEFA-PLUS led CEN workshop on this aspect. Towards the end of the project it is planned that INCEFA-PLUS will develop and disseminate methods for including the new data into assessment approaches for environmental fatigue degradation. This paper provides an overall update on project developments since it was last presented at PVP2018 [1]. As well as being a standalone paper, this document will also serve as an introduction to a companion paper being submitted to cover data generated by the project in more detail [2]. In particular, this paper summarises: • The results for Phases 1 & 2 testing. • The plans for Phase 3 testing. • A summary of emerging sensitivities to, and interdependencies between: o Mean strain and stress, surface finish, strain amplitude and hold time. o Environment. o Material. o Laboratory. • The latest thinking on the direction of the project in its final year. • The latest thoughts on how the project results will be used to advance development of improved assessment guidelines. • A summary of dissemination achieved and planned. • Ideas for work after the end of INCEFA-PLUS.

INCEFA-PLUS: Increasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment

2018 ◽  
Author(s):  
Kevin Mottershead ◽  
Matthias Bruchhausen ◽  
Sam Cuvilliez ◽  
Sergio Cicero
Keyword(s):  
Strain Amplitude ◽  
Surface Finish ◽  
Nuclear Power ◽  
Power Plants ◽  
Phase 1 ◽  
Hold Time ◽  
Austenitic Stainless Steels ◽  
Common Interest ◽  
Horizon 2020 ◽  
Mean Strain

INCEFA-PLUS is a five-year project supported by the European Commission HORIZON 2020 programme. The project commenced in mid-2015. Sixteen organisations from across Europe have combined forces to deliver new experimental data which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain and stress, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments are being studied experimentally, these being issues of common interest to all participants. The data obtained is being collected and standardised in an online environmental fatigue database, implemented with the assistance of an INCEFA-PLUS led CEN (European Committee for Standardization) workshop on this aspect. Later in the project it is planned that INCEFA-PLUS will develop and disseminate methods for including the new data into assessment approaches for environmental fatigue degradation. This paper provides an overall update to project developments since it was last presented at PVP2017 [[1]]. As well as being a standalone paper, the paper will also serve as an introduction to more detailed papers also being submitted covering 4 specific aspects of the project. In particular, this paper summarises: • The results for Phase 1 testing. • The agreed plans for Phase 2 testing • A summary of emerging sensitivities to, and inter-dependencies between: ○ Mean strain and stress, surface finish, strain amplitude and hold time. ○ Environment ○ Material ○ Laboratory • Latest thinking on direction for the project in its last two years. • The latest thoughts on how the project results will be used to advance development of improved assessment guidelines. • A summary of dissemination achieved and planned for the forthcoming year.

scholarly journals INCEFA-PLUS (Increasing Safety in Nuclear Power Plants by Covering Gaps in Environmental Fatigue Assessment)

2016 ◽  
Author(s):  
Kevin Mottershead ◽  
Matthias Bruchhausen ◽  
Thomas Métais ◽  
Sergio Cicero ◽  
David Tice ◽  
...  
Keyword(s):  
Surface Finish ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Hold Time ◽  
Austenitic Stainless Steels ◽  
Mean Stress ◽  
Stress Strain ◽  
Assessment Procedures ◽  
Strain Hold

INCEFA-PLUS is a major new five year project supported by the European Commission HORIZON2020 program. The project commenced in mid 2015. 16 organizations from across Europe have combined forces to deliver new experimental data which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Prior to the start of INCEFA-PLUS, an in-kind study was undertaken by several European organizations with the aim of developing the current state of the art for this technical area. In addition to stress/strain amplitude, this study identified three additional experimental variables which required further study in order to support improved assessment methodology for environmental fatigue, namely the effects of mean stress/strain, hold time and surface finish. Within INCEFA-PLUS, the effects of these three variables on fatigue endurance of austenitic stainless steels in light water reactor environments are therefore being studied experimentally. The data obtained will be collected and standardized in an online environmental fatigue database. A dedicated CEN workshop will deliver a harmonized data format facilitating the exchange of data within the project but also beyond. Based on the data generated and the resulting improvement in understanding, it is planned that INCEFA-PLUS will develop and disseminate methods for including the new data into assessment procedures for environmental fatigue degradation. This will take better account of the effects of mean stress/strain, hold time and surface finish. This paper will describe the background to the project and will explain the expectations for it.

scholarly journals INCEFA-PLUS (Increasing Safety in Nuclear Power Plants by Covering Gaps in Environmental Fatigue Assessment)

2017 ◽  
Author(s):  
Kevin Mottershead ◽  
Matthias Bruchhausen ◽  
Thomas Métais ◽  
Sergio Cicero ◽  
David Tice
Keyword(s):  
Test Data ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Phase 1 ◽  
Hold Time ◽  
Austenitic Stainless Steels ◽  
Common Interest ◽  
Mean Stress ◽  
Surface Finishes

INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 program. The project commenced in mid-2015. 16 organizations from across Europe have combined forces to deliver new experimental data which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments are being studied experimentally, these being issues of common interest to all participants. The data obtained are being collected and standardized in an online environmental fatigue database, implemented with the assistance of a CEN workshop led by members of the INCEFA-PLUS project. Later in the project it is planned that INCEFA-PLUS will develop and disseminate methods for including the new data into assessment approaches for environmental fatigue degradation. This paper provides an update to the project introduction presented at PVP2016 (PVP2016-63149). In particular the paper presents the finalized matrix of test conditions for Phase 1 testing planned for 2017, including the agreed positions on testing for the effects of mean stress/strain and hold time. The materials being tested are summarized, together with available material characterization data. The specimen surface finishes used in the phase 1 testing are described, including measures taken to ensure uniformity of surface conditions throughout the consortium and characterization results for the two chosen surface finishes for each specimen geometry and material. The emerging plans for Phase 2 testing is also described, with a focus on steps being taken to enable more plant-relevant testing for the effects of mean stress and exploration of sensitivities to hold times within plant transients. The latest view on how the project results will be used to advance development of improved assessment guidelines is also discussed. An update is provided on the discussions at the CEN workshop on Standards-Compliant Formats for Fatigue Test Data (FATEDA) including progress towards agreeing test data formats and trials of XML data transfers from laboratory to database. Finally, a summary is provided of project dissemination activities.

scholarly journals Characterization of Austenitic Stainless Steels with Regard to Environmentally Assisted Fatigue in Simulated Light Water Reactor Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 307
Author(s):  
Matthias Bruchhausen ◽  
Gintautas Dundulis ◽  
Alec McLennan ◽  
Sergio Arrieta ◽  
Tim Austin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Elevated Temperature ◽  
Strain Rate ◽  
Power Plants ◽  
Research Effort ◽  
Hold Time ◽  
Strain Range ◽  
Austenitic Steels ◽  
Mean Strain

A substantial amount of research effort has been applied to the field of environmentally assisted fatigue (EAF) due to the requirement to account for the EAF behaviour of metals for existing and new build nuclear power plants. We present the results of the European project INcreasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment (INCEFA-PLUS), during which the sensitivities of strain range, environment, surface roughness, mean strain and hold times, as well as their interactions on the fatigue life of austenitic steels has been characterized. The project included a test campaign, during which more than 250 fatigue tests were performed. The tests did not reveal a significant effect of mean strain or hold time on fatigue life. An empirical model describing the fatigue life as a function of strain rate, environment and surface roughness is developed. There is evidence for statistically significant interaction effects between surface roughness and the environment, as well as between surface roughness and strain range. However, their impact on fatigue life is so small that they are not practically relevant and can in most cases be neglected. Reducing the environmental impact on fatigue life by modifying the temperature or strain rate leads to an increase of the fatigue life in agreement with predictions based on NUREG/CR-6909. A limited sub-programme on the sensitivity of hold times at elevated temperature at zero force conditions and at elevated temperature did not show the beneficial effect on fatigue life found in another study.

INCEFA-PLUS Project: Lessons Learned From the Project Data and Impact on Existing Fatigue Assessment Procedures

2020 ◽  
Author(s):  
Sam Cuvilliez ◽  
Alec McLennan ◽  
Kevin Mottershead ◽  
Jonathan Mann ◽  
Matthias Bruchhausen
Keyword(s):  
Surface Finish ◽  
Environmental Effects ◽  
Nuclear Power ◽  
Power Plants ◽  
Lessons Learned ◽  
Fatigue Assessment ◽  
Data Points ◽  
Project Data ◽  
Assessment Procedures ◽  
Surface Finish Effect

Abstract The INCEFA+ project (INcreasing Safety in nuclear power plants by Covering gaps in Environmental Fatigue Assessment) is a five year project supported by the European Commission HORIZON2020 programme, which will conclude in June 2020. This project aims to generate and analyse Environmental Assisted Fatigue (EAF) experimental data (approximately 230 fatigue data points generated on austenitic stainless steel), and focuses on the effect of several key parameters such as mean strain, hold times and surface finish, and how they interact with environmental effects (air or PWR environment). This work focuses on the analysis of the data obtained during the INCEFA+ project. More specifically, this paper discusses how the outcome of this analysis can be used to evaluate existing fatigue assessment procedures that incorporate environmental effects in a similar way to NUREG/CR-6909. A key difference between these approaches and the NUREG/CR-6909 is the reduction of conservatisms resulting from the joint implementation of the adjustment sub-factor related to surface finish effect (as quantified in the design air curve derivation) and a Fen penalization factor for fatigue assessment of a location subjected to a PWR primary environment. The analysis presented in this paper indicates that the adjustment (sub-)factor on life associated with the effect of surface finish in air (as described in the derivation of the design air curve in NUREG/CR-6909) leads to substantial conservatisms when it is used to predict fatigue lifetimes in PWR environments for rough specimens. The corresponding margins can be explicitly quantified against the design air curve used for EAF assessment, but may also depend on the environmental correction Fen factor expression that is used to take environmental effects into account.

Fracture Toughness Predictive Models Within the SOTERIA EU Project

2018 ◽  
Author(s):  
P. M. James ◽  
M. Berveiller
Keyword(s):  
Cleavage Fracture ◽  
Nuclear Power ◽  
Power Plants ◽  
Radiation Effects ◽  
Austenitic Stainless Steels ◽  
Irradiation Damage ◽  
Tensile Behaviour ◽  
Horizon 2020 ◽  
Term Operation

SOTERIA is focused on the ‘safe long term operation of light water reactors’. This will be achieved through an improved understanding of radiation effects in nuclear structural materials. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under agreement No 661913. The overall aim of the SOTERIA project is to improve the understanding of the ageing phenomena occurring in ferritic reactor pressure vessel steels and in the austenitic internals in order to provide crucial information to regulators and operators to ensure safe long-term operation (LTO) of existing European nuclear power plants (NPPs). SOTERIA has set up a collaborative research consortium which gathers the main European research centers and industrial partners who will combine advanced modelling tools with the exploitation of experimental data to focus on two major objectives: i) to identify ageing mechanisms when materials face environmental degradation (such as e.g. irradiation and corrosion) and ii) to provide a single platform containing data and tools for reassessment of structural components during NPPs lifetime. This paper provides an overview of the ongoing activities within the SOTERIA Project that are contained within the analytical work-package (WP5.3). These fracture aspects are focused on the estimates of fracture in both ferritic steels and irradiation assisted stress corrosion cracking (IASCC) in austenitic stainless steels, under irradiated conditions. This analytical development is supported by analytical estimates of irradiation damage and the resulting changes in tensile behaviour of the steels elsewhere in SOTERIA, as well as a wider number of experimental programmes. Cleavage fracture estimates are being considered by a range of modelling estimates including the Beremin, Microstructurally Informed Brittle Fracture Model (MIBF), JFJ and Bordet Models with efforts being made to understand the influence of heterogeneity on the predicted toughness’s. Efforts are also being considered to better understand ductile void evolution and the effect of plasticity on the cleavage fracture predictions. IASCC is being modelled through the INITEAC code previously developed within the predecessor project Perform 60 which is being updated to incorporate recent developments from within SOTERIA and elsewhere.

Online Fault Diagnosis of Nuclear Power Plants Using Signed Directed Graph and Fuzzy Theory

2017 ◽  
Author(s):  
Guohua Wu ◽  
Liguo Zhang ◽  
Jiejuan Tong
Keyword(s):  
Directed Graph ◽  
Nuclear Power ◽  
Power Plants ◽  
Fuzzy Theory ◽  
Fault Detection And Diagnosis ◽  
Propagation Path ◽  
Simulation Experiments ◽  
Safety Standards ◽  
Signed Directed Graph ◽  
The Status

When nuclear power plant (NPPs) is in fault, it may release radioactivity into the environment. Therefore, extremely high safety standards specification are required during its working. So it is critically important for fault detection and diagnosis (FDD). NPPs are composed of large and complex systems, it is of great significance to obtain the up-to-date information of NPPs’ running state. So FDD is used to provide the state of system accurately and timely in NPPs. Signed directed graph (SDG) can show the complex relationship between parameters and has advantages of conveniently modeling, flexible inference and so on, so SDG is adopted for FDD. To achieve SDG inference better, fuzzy theory is utilized for signal processing in the paper. Firstly, SDG model is built according to the basic steps and principles of SDG modeling, and the parameters are divided into three states which is monitored by fuzzy theory. Secondly, according to the status of parameters, SDG is used for FDD and to reveal the fault propagation path, thus possibility of each fault occurred is achieved. Finally, to verify the validity of the method, the simulation experiments are done for NPPs and the simulation experiments show that SDG-fuzzy theory framework for FDD can get the fault possibility and deeply explain the reasons of fault.

AP1000 Operation Procedures System and Development

2010 ◽  
Author(s):  
Fang Wen
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Flow Process ◽  
Human Factor Engineering ◽  
Data Process ◽  
Operation Procedure ◽  
The Status ◽  
Procedure Classification ◽  
Plant Data ◽  
Westinghouse Electric

This paper makes a brief introduction on AP1000 operation procedure system, including procedure classification, function and composition. In addition, key points of work flow process and the advantages of AP1000 operation procedures are described, among which the application of CPS (computerized procedure system) on AP1000 operation area and human factor engineering are highlighted. CPS, as an advanced procedure system, which is relatively new to existing nuclear power plants in China, does not only have the function of electronic indication for procedures, but also have the ability to monitor plant data, process the data and then present the status of the procedure steps to the reactor operator. Moreover, based on current situation, this paper offers several suggestions on procedure development for Sanmen AP1000 nuclear power project, i.e. first, we can ensure the quality of operation procedures by preparing a precise writer’s guideline, a friendly-interfaced procedure template, an efficient work configuration and an appropriate schedule; then determine the way how we are going to use operation procedures in English version; finally realize CPS Chinesization and localization gradually by digesting and absorbing API 000 technology from Westinghouse Electric Company. This paper gives an intact and systematic discourse on AP1000 operation procedure system and its characteristics. Besides, the latter part of this paper focuses on development of AP1000 operation procedures for Sanmen nuclear power plant and it would be a worthwhile reference for newly-built AP1000 units in China.

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