scholarly journals Broadening the Amplitude in the Definition of Structural Integrity: A Tribute to Galileo Galilei

2021 ◽  
Vol 33 ◽  
pp. 1123-1130
Author(s):  
Jesús Toribio
Keyword(s):  
Structural Integrity ◽  
Galileo Galilei ◽  
Definition Of

French R&D Program for RPV Aging Management

2004 ◽  
Author(s):  
H. Churier-Bossennec ◽  
D. Moinereau ◽  
P. Todeschini ◽  
C. Faidy ◽  
G. Bezdikian
Keyword(s):  
Structural Integrity ◽  
Probabilistic Approach ◽  
Development Program ◽  
Surveillance Program ◽  
Integrity Assessment ◽  
Large Program ◽  
Periodic Safety ◽  
Long Lifetime ◽  
Definition Of ◽  
Mitigation Methods

Until now French approach for RPV PTS assessment is based on at least 40 years lifetime. This lifetime has been taken into account at each step of the the RPV life: first early in the design, then at each periodic safety demonstration by including the surveillance program, the national and international feedback and R&D results. All of them confirm that all the 3-loop French RPV fulfill the existing criteria for at least 40 years of operation. In order to evaluate their capability to operate for 60 years, an Engineering and Research and Development program has been recently established and engaged by EDF. This large program of activities between all of divisions of EDF is focused on the different fields involved in the risk of fast rupture of the irradiated core vessel. The main purposes of this programme are: • the research of specific data corresponding to a long lifetime of about 60 years; • the studies of new methods to improve the demonstration including several themes such as fluence evaluation, determination of fracture toughness, structural integrity assessment including probabilistic approach, definition of transients; • the evaluation of mitigation methods. This paper contains first a description of what was done at each RPV PTS assessment and an overview of the present program.

Material Properties of Reactor Pressure Vessel Shells Affected by Hydrogen Flaking

2016 ◽  
Author(s):  
Robert Gérard ◽  
Michel De Smet ◽  
Rachid Chaouadi
Keyword(s):  
Fracture Toughness ◽  
Material Properties ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Operating Cycle ◽  
Safety Case ◽  
Safety Cases ◽  
Definition Of ◽  
Reactor Pressure ◽  
Trend Curve

During the summer outages of 2012, large numbers of nearly-laminar indications were found in the core shells of the Doel 3 and Tihange 2 reactor pressure vessels (RPV). As a consequence, both units remained in cold shutdown with their core unloaded. A series of examinations, tests and inspections were performed leading to the conclusion that the indications are hydrogen flakes and that they do not affect the structural integrity of the RPV, regardless of the operating mode, transient or accident condition. All this was documented in the Safety Case reports issued in December 2012 and in the Safety Case Addenda issued in April 2013 [1]. Based on those reports, the Belgian Federal Agency for Nuclear Control (FANC) authorized the restart of both units which went back on-line in June 2013. A key input required for this Safety Case was the definition of the appropriate material properties, in particular fracture toughness, for the RPV shells affected by hydrogen flakes. A material testing program on non-irradiated materials evaluated aspects like the possible effects of macro-segregations and local segregations (ghost lines) and of specimen orientation on the fracture toughness. The irradiation embrittlement sensitivity of the zone of macro-segregation in which the flakes are located was evaluated on the basis of the maximum enrichment in Cu, P and Ni in macro-segregations based on literature data. This was the basis of the trend curve of RTNDT evolution vs. fluence used in the Safety Cases submitted in 2012–2013. The restart authorization in 2013 was accompanied by a number of “mid-term” requirements, to be completed during the first operating cycle after the restart. One of these requirements was the mechanical testing of irradiated specimens containing hydrogen flakes, in order to confirm the conservativeness of the RTNDT trend curve used for the structural integrity analyses. After a first irradiation campaign of a material containing hydrogen flakes in the BR2 reactor of the Belgian Nuclear Research Center SCK.CEN, atypical results were obtained and the utility decided to shut down the units in March 2014. Detailed investigations involving three additional irradiation campaigns in BR2 including other reference materials, among which another material affected by hydrogen flakes, were performed in order to characterize this atypical behaviour and to derive a new conservative RTNDT trend curve. The resulting trend curve was accepted by the FANC and was used in the 2015 Safety Cases [1]. An overview of the Doel 3 and Tihange 2 safety cases is given in [6]. The paper summarizes the results of the material investigations on non-irradiated and irradiated materials and the process leading to the definition of this conservative RTNDT trend curve.

Safety Format and Acceptance Criteria for Analysis of Marine Structures Using Non-Linear Methods

2011 ◽  
Author(s):  
Gunnar Solland ◽  
Atle Johansen ◽  
Gudfinnur Sigurdsson
Keyword(s):  
Cross Sections ◽  
Structural Integrity ◽  
Linear Analysis ◽  
Acceptance Criteria ◽  
Existing Structures ◽  
Analysis Methods ◽  
Structural Details ◽  
Non Linear ◽  
Definition Of ◽  
Novel Design

This paper deals with how structural integrity can be documented by use of non-linear analysis methods. The focus is on structures that are exposed to extreme environmental loads. In order to prove the structural integrity for aging offshore installation, non-linear analysis methods are finding increased applications. The codes ISO 19902, API RP 2A and Norsok N-006 give recommendations for use of non-linear methods for capacity checks of existing structures. This paper discusses the different safety formats given in these codes. Also presented is how practical acceptance criteria that have to be applied in conjunction with such analyses can be formulated. The topics that are dealt with are issues that the analyst performing such analyses needs to address like: definition of failure, representation of joints, issues on cyclic loading, instability of cross sections and member buckling. In cases of novel design solutions or special structural details, non-linear analysis methods may also find application when planning new structures.

scholarly journals Multi-Genre Strategies of “Walking with Pushkin” by A. Terts (A. Sinyavsky)

2021 ◽  
pp. 173-191
Author(s):  
O. V. Bogdanova ◽  
E. A. Vlasova
Keyword(s):  
World Literature ◽  
Structural Integrity ◽  
State University ◽  
Narrative Strategies ◽  
History Of ◽  
Characteristic Features ◽  
Definition Of ◽  
Academy Of Sciences ◽  
Structural Research ◽  
Relationship Of

Based on the material of the book “Walking with Pushkin” by Abram Terts (Andrey Sinyavsky), the goal is to determine the main narrative strategies that the writer implemented. The authors demonstrate that along with the genre definitions of “novel”, “novella”, “essay”, the narrative is mediated by the techniques of “philological prose” and scientific discourse. It is shown that markers of scientific discursively narrative SinyavskyTerts in “Walking with Pushkin” is the number of characteristic features: composite partitioning, the extension of the goals and objectives  of  the   analysis,   the   coverage of  the  history  of  the  problem,  selection   of  research  methodology,  the   definition   of the novelty of the work, the establishment of perspectives, providing structural integrity, respect of chronology in understanding material, the use of the bibliographic apparatus, etc. According to the authors, the experience of Sinyavsky, a research scientist, who defended the dissertation at MSU, working in world literature of the Academy of Sciences of the USSR, who read lectures at Moscow state University and the Moscow art theatre Studio, influenced the nature of the material in  the  “Walking.” and served as canon  of  structural  research. It is established that a “free”    manner    of    presentation of scientific observations is expressive means of focusing attention on the most pressing issues  of  domestic scientists  to update the relationship of history and modernity (his understanding of own creativity, manifestation of the principle of “pure art”, the semantics  of the principle of freedom within the literature of socialist realism, etc.).

Validation of Constraint Based Methodology in Structural Integrity – VOCALIST: Project Overview

2002 ◽  
Author(s):  
David Lidbury ◽  
Richard Bass ◽  
Elisabeth Keim ◽  
Surender Bhandari ◽  
David Connors ◽  
...  
Keyword(s):  
Best Practice ◽  
Structural Integrity ◽  
Crack Tip ◽  
Constraint Effect ◽  
Defect Assessment ◽  
Safety Margins ◽  
Action Project ◽  
Definition Of ◽  
Crack Tip Constraint ◽  
Energy Community

VOCALIST (Validation of Constraint Based Methodology in Structural Integrity) is a shared cost action project co-financed by the European Commission under the Fifth Framework of the European Atomic Energy Community (EURATOM). The motivation for VOCALIST is based on the observation that the pattern of crack-tip stresses and strains causing plastic flow and fracture in components is different to that in test specimens. This gives rise to the so-called constraint effect. Crack-tip constraint in components is generally lower than in test specimens. Effective toughness is correspondingly higher. The fracture toughness measured on test specimens is thus likely to underestimate that exhibited by cracks in components. The purpose of VOCALIST is to develop validated models of the constraint effect, and associated best practice advice, with the objective of achieving (i) an improved defect assessment methodology for predicting safety margins; (ii) improved lifetime management arguments. The work is intended to be of benefit to both plant operators and their regulators. The project started in October 2000 and will run for thirty-six months. The main achievements to date are as follows: • Identification and assessment of current issues affecting the application of constraint-based fracture assessment methods in practical situations. • Materials selection and identification of test matrices. • Initiation of characterisation testing. • Detailed definition of analytical programme and alignment with experimental programme. • Definition of test conditions for Benchmark and Features tests. • Procurement and execution of Benchmark tests. • Procurement and execution of scoping Features tests. This paper provides an overview of VOCALIST, describes its various Work Packages, and provides an up-to-date summary of progress as the project reaches mid-term.

How to Select the Optimized Time Step and Mesh Size for FEM Thermal Transients Simulations of PWR Vessels and Nozzles by Means of Artificial Neural Networks

2019 ◽  
Author(s):  
Nicolas Santucho ◽  
Martin Chimenti ◽  
Jose Duo
Keyword(s):  
Data Base ◽  
Structural Integrity ◽  
Mesh Size ◽  
Time Step ◽  
Thermal Transients ◽  
Element Size ◽  
Mechanical Models ◽  
Allowable Error ◽  
Artificial Neural ◽  
Definition Of

Abstract This paper describes the development of a data base and associated interpolation tool used to perform the validation of FEA thermo-mechanical models designed to verify the structural integrity of a self-pressurized modular Reactor Pressure Vessel (RPV) and its nozzles under service transient thermal loads. The main goal is to assess the element’s size and time steps that provide a confidence level on the obtained solutions. The validation process implies the definition of the geometry under study, its material’s properties, thermal load conditions and type of mesh element. With all this information, the program gives the user a set of curves for maximum time steps vs. temperature change rates for each typical thickness section in the modeled geometry for a chosen element size. Any point located below those curves assures a solution underneath a user specified allowable error (e.g.: 5%). All calculations are processed using dimensionless variables in order to create a universal data base enabling the analysis of many different situations of geometries, materials and loads. To improve performance, an Artificial Neural Network algorithm was developed. The resulting application significantly reduces the convergence study time and efforts.

Structural Integrity Assessment of a Pipeline Subjected to an Underwater Explosion

2011 ◽  
Author(s):  
Paolo Monti ◽  
Caterina Molinari ◽  
Massimiliano Bocciarelli ◽  
Alberto Corigliano ◽  
Stefano Mariani
Keyword(s):  
Structural Integrity ◽  
Underwater Explosion ◽  
Structural Response ◽  
Potential Hazard ◽  
Limit States ◽  
Integrity Assessment ◽  
Definition Of ◽  
Bubble Pulsation ◽  
Numerical Approaches

Several trunklines cross either areas which in the recent past were war theatre or dumping areas used for burying weapons after the last war. The presence of unexploded mines, bombs or torpedoes on the seabed constitutes a potential hazard for the structural integrity of submarine pipelines. Before laying, it is therefore necessary to remove the unexploded charges within a corridor including the route. Risk still remains during the pipeline life, since annual surveys can show evidences of unexploded mines or torpedoes dragged by fishing gears till the protruding pipeline. Consequently, the structural integrity assessment of a submarine pipeline subjected to underwater explosions is of the utmost importance. The aforementioned assessment involves several aspects: the characterization of shock wave and gas bubble pulsation in water; the definition of loading conditions on the pipeline; the characterisation of the strain-rate properties of the steel; the local and global structural analysis; the pipe verification criteria. Aim of this study is to describe how the aforementioned aspects can be managed. Analytical and numerical approaches concerning the assessment of the structural response of the pipeline are presented, and criteria for Serviceability and Accidental Limit States are proposed.

On-Line Monitoring and Warning of Important In-Service Pressure Equipment Based on Characteristic Safety Parameters

2017 ◽  
Author(s):  
Xuedong Chen ◽  
Tiecheng Yang ◽  
Zhichao Fan ◽  
Yunrong Lv
Keyword(s):  
Big Data ◽  
Real Time ◽  
Failure Mechanism ◽  
Failure Modes ◽  
Structural Integrity ◽  
Safety Margin ◽  
Measurement Monitoring ◽  
Safety Parameters ◽  
Safety Parameter ◽  
Definition Of

Characteristic safety parameter refers to the parameter that reflects the inherent safety margin of pressure equipments subjected to certain failure mechanism. It has three main characteristics. Firstly, it is sensitive to the change in failure mechanism. Secondly, the safety of pressure equipments can be guaranteed by controlling this parameter. Thirdly, it is easy to measure. By real-time monitoring of this characteristic safety parameter, the quantitative assessment of the structural integrity and furhter the diagnosis and warning on the safety of in-service pressure equipments can be realized. In this paper, the definition of characteristic safety parameter is given first for the pressure equipments subjected to several typical failure modes. After that, the selection principle, measurement technique and determination of its critical value, etc., are then introduced by analyzing typical examples. In combination with the technical concepts of the Internet of Things and Big-Data, some research suggestions are proposed with respect to the remote monitoring and diagnosis techniques based on the characteristic safety parameter, including the sensing measurement, monitoring and analysis of big data, real-time diagnosis and early warning of safety condition, etc.

scholarly journals Remote Monitoring of Floating Covers Using UAV Photogrammetry

2020 ◽  
Vol 12 (7) ◽  
pp. 1118 ◽  
Author(s):  
Leslie Wong ◽  
Benjamin Steven Vien ◽  
Yue Ma ◽  
Thomas Kuen ◽  
Frank Courtney ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Wastewater Treatment Plants ◽  
Health Assessment ◽  
Treatment Plant ◽  
Renewable Resource ◽  
The State ◽  
Integrity Assessment ◽  
Structural Health Assessment ◽  
Aerial Vehicle ◽  
Definition Of

High-density polyethylene (HDPE) is commonly the material of choice for covered anaerobic lagoons (CAL) at wastewater treatment plants. The membrane floats on the wastewater, and hence is called a “floating cover”, and is used for odour control and to harvest the methane-rich biogas as a renewable resource to generate electricity. The floating cover is an expensive and high-value asset that demands an efficient methodology for the determination of a set of engineering quantities for structural integrity assessment. Given the dynamics of the anaerobic activities under the floating cover, the state of deformation of the floating cover is an engineering measurand that is useful for its structural health assessment. A non-contact measurement strategy is preferred as it offers practical and safety-related benefits over other methods. In collaboration with Melbourne Water Corporation (MWC), an unmanned aerial vehicle (UAV) assisted photogrammetry approach was developed to address this need. Following the definition of the appropriate flight parameters required to quantify the state of deformation of the cover, a series of periodic flights were operated over the very large floating covers at MWC’s Western Treatment Plant (WTP) at Werribee, Victoria, Australia. This paper aims to demonstrate the effectiveness and practicality of this inspection technique to determine the state of deformation of the floating covers measured over a ten-month period.

Sign in / Sign up

Export Citation Format

Share Document