Structural integrity assessment and lifetime prediction for the control rods couplings of the WWER-440 reactor. Part 2. Assessment of the coupling structural integrity and justification of its material degradation monitoring interval

2021 ◽  
pp. 163-176
Author(s):  
A. J. Minkin ◽  
B. Z. Margolin ◽  
V. G. Fedosov
Keyword(s):  
Stainless Steel ◽  
Vickers Hardness ◽  
Structural Integrity ◽  
Steel Grade ◽  
Material Degradation ◽  
Control Rod ◽  
Integrity Assessment ◽  
Degradation Monitoring ◽  
Radiation Induced ◽  
Control Rods

The structural integrity of the control rods couplings of the WWER-440 reactor is analyzed. On the basis of material investigation of the control rod couplings (martensitic-ferritic stainless steel grade 14Kh17N2, analogue of AISI 431 steel) that were under operation in the Unit 3 of Novovoronezh NPP it is shown that the structural integrity of the coupling is satisfied until the radiation-induced hardening of its material does not exceed 423 units of Vickers hardness.

Structural integrity assessment and lifetime prediction for the control rods couplings of the WWER-440 reactor. Part 3. Optimi- zation of post-irradiation recovery annealing of the control rods couplings

2021 ◽  
pp. 177-191
Author(s):  
A. J. Minkin ◽  
B. Z. Margolin ◽  
L. A. Belyaeva ◽  
N. E. Pirogova ◽  
A. M. Shumko ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Structural Integrity ◽  
Complete Recovery ◽  
Steel 08Kh18n10t ◽  
Control Rod ◽  
Integrity Assessment ◽  
Post Irradiation ◽  
Recovery Annealing ◽  
Aisi 321 ◽  
Control Rods

The optimization of post-irradiation recovery annealing of metal of control rods couplings (marten- sitic-ferritic stainless steel 14Kh17N2 grade, analogue of AISI 431 steel) is carried out. It is shown that the optimized recovery annealing leads to complete recovery of the mechanical properties of coupling metal embrittled under neutron irradiation. The recovery annealing does not reduce corrosion resistance of control rod tube made of austenitic stainless steel 08Kh18N10T grade (analogue of AISI 321 steel).

Elastic-Plastic Fracture Mechanics Analysis of Cast Stainless Steel Pipes (Influence of Axial Load on Z-Factor of Pipes With Circumferential Crack Under Bending Load)

2013 ◽  
Author(s):  
Masayuki Kamaya ◽  
Kiminobu Hojo
Keyword(s):  
Stainless Steel ◽  
Axial Load ◽  
Power Plants ◽  
Structural Integrity ◽  
Term Operation ◽  
Steel Pipes ◽  
Integrity Assessment ◽  
Plastic Failure ◽  
Elastic Plastic ◽  
Bending Load

Since the ductility of cast austenitic stainless steel pipes decreases due to thermal aging embrittlement after long term operation, not only plastic collapse failure but also unstable ductile crack propagation (elastic-plastic failure) should be taken into account for the structural integrity assessment of cracked pipes. In the ASME Section XI, the load multiplier (Z-factor) is used to derive the elastic-plastic failure of the cracked components. The Z-factor of cracked pipes under bending load has been obtained without considering the axial load. In this study, the influence of the axial load on Z-factor was quantified through elastic-plastic failure analyses under various conditions. It was concluded that the axial load increased the Z-factor; however, the magnitude of the increase was not significant, particularly for the main coolant pipes of PWR nuclear power plants.

Environmental Crack Growth Predictions for Piping Components

2007 ◽  
Author(s):  
Sam Ranganath ◽  
Guy DeBoo
Keyword(s):  
Stainless Steel ◽  
Crack Growth ◽  
Test Data ◽  
Structural Integrity ◽  
Reference Curve ◽  
Pressurized Water ◽  
Water Reactor ◽  
Integrity Assessment ◽  
Asme Code ◽  
Reference Curves

Structural integrity assessment of reactor components requires consideration of crack growth. A key input to this is the development of reference stress corrosion crack (SCC) growth rate curves for use in the structural evaluation. The ASME Section XI Task Group on SCC Reference Curve is looking into available SCC data for stainless steel and nickel based alloys and associated weldment in both pressurized water reactor (PWR) and boiling water reactor (BWR) environments. The test data show significant data scatter in crack growth rates (CGR). The conservative approach is to develop reference curves that bound all available data so that upper bound crack growth predictions. While this approach may be conservative, it may lead to excessive estimates of crack growth and result in unrealistic (and often meaningless) structural margin predictions. Selection of the appropriate SCC reference curves requires realistic interpretation of test data so that the predictions are consistent with field behavior and provide reasonable, but conservative assessment. This paper describes crack growth assessment for stainless steel piping and Alloy 600 safe end components with Alloy 182/82 welds in BWR environment. The results from the crack growth analysis for piping can be used to determine whether a proposed reference curve provides reasonable results. The objective is to use the piping and safe end crack growth predictions to develop optimal SCC Reference Curves for use in ASME Code evaluations.

The Influence of AGR Gas Carburisation on the Creep and Fracture Properties of Type 316H Stainless Steel

2016 ◽  
Author(s):  
Mustafa Nasser ◽  
Catrin M. Davies ◽  
Kamran Nikbin
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Structural Integrity ◽  
Substantial Reduction ◽  
Creep Crack Growth ◽  
Creep Rupture ◽  
Rupture Time ◽  
Metallographic Examination ◽  
Fracture Properties ◽  
Integrity Assessment

Defects in the UK’s AGR nuclear reactors have been historically found in superheater regions of the boilers. These components are fabricated from type 316H austenitic stainless steel and operate in carbon dioxide gas coolant environments under creep conditions, at temperatures up to 550°C. As a result, some components maybe carburised throughout their life resulting in the formation of a hardened outer surface layer. This layer results from interstitial carbon diffusion and is thought to impact on the creep, creep-fatigue and fracture properties of 316H. Carburisation is currently unaccounted for within high temperature structural integrity assessment procedures. It is essential that carburisation and resulting damage mechanisms are well understood in order to accurately predict the failure of components. This paper aims to investigate the effect of AGR gas carburisation on the creep and fracture properties of type 316H stainless steel. Specimens have been preconditioned within a simulated AGR gas environment. The presence of carburisation has been confirmed through metallographic examination, hardness testing and surface analysis techniques. A series of constant load high-temperature creep tests have been conducted on preconditioned specimens. Compared to as-received material, carburised specimens displayed a significant reduction in creep rupture time with cracking of the outer carburised layer initiating creep crack growth. This phenomenon is seen to occur at very low strains and has been confirmed through interrupted creep testing. The substantial reduction in creep rupture time is postulated to result from embrittlement of the carburised material owing to strong precipitation of carbides along grain boundaries. It is concluded that carburisation can lead to a severe reduction in creep rupture life in test conditions; the possible implications of this with regards to plant conditions are discussed.

scholarly journals Residual Stress Measurement in a Stainless Steel Clad Ferritic Plate Using the Contour Method

2013 ◽  
Author(s):  
Nida Naveed ◽  
Foroogh Hosseinzadeh ◽  
Jan Kowal
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Stress Measurement ◽  
Base Material ◽  
Pressure Vessels ◽  
Contour Method ◽  
Steel Weld ◽  
Integrity Assessment ◽  
Stainless Steel Weld

In pressure vessels stainless steel weld-overlay cladding is a widely used technique to provide a protective barrier between the corrosive environment and the ferritic low alloy base metal. While the cladding layers enhance corrosion resistance, the induced residual stresses due to the deposition of weld layers are of major concern. It is of paramount importance to understand how residual stresses interact with service loading when the vessel is pressurized. Therefore, knowledge of the initial residual stresses due to cladding is an essential input for structural integrity assessment of pressure vessels. In the present paper the Contour Method was conducted to measure residual stresses in an austenitic steel cladded plate that was fabricated from a ferritic steel base plate with three layers of austenitic stainless steel weld metal cladding deposited on the top surface. The Contour Method was chosen for various reasons. First, it provides a full 2D variation of residual stresses over the plane of interest. Second, it is not limited by the thickness of components or microstructural variations and finally it should potentially capture the variation of residual stresses in each individual weld beads and due to the possible phase transformation in the ferritic base material. The map of longitudinal residual stresses was measured by sectioning the test component along a transverse plane at mid-length. The measured residual stresses were in good agreement with published results in the open literature.

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.

Fracture Assessment of the High Strength Super-Martensitic Stainless Steel Welds by SINTAP Defect Assessment Procedure

2003 ◽  
Author(s):  
A. K. Motarjemi ◽  
M. Koc¸ak ◽  
R. Segar ◽  
S. Riekehr
Keyword(s):  
Stainless Steel ◽  
Carrying Capacity ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Welding Process ◽  
Assessment Procedure ◽  
Load Carrying Capacity ◽  
Deformation And Failure ◽  
Integrity Assessment ◽  
Load Carrying

13% Cr supermartensitic stainless steel is an adequate substitute material for the conventional carbon and duplex stainless steel pipes for mild corrosive environments in the oil and gas industries. By development of these new steel and respective welding technologies, structural integrity analysis of the welded pipes, is essential and a challenging task. Depending on the welding process, filler wire used, the deformation and failure behaviours of the welded pipes could be different. In this study, fitness for service analysis verified with Submerged Arc welded Middle Tension, M(T), plates as well as for the reeling deformation during the pipe-laying process. This was done by applying analysis Levels 0, I, II and III of a recently developed European Structural Integrity Assessment Procedure (SINTAP). The goal was first of all to verify SINTAP’s load-carrying capacity predictions for welded M(T) specimens (wide plates) by comparing them with corresponding experimental data. SINTAP was also used for estimating the maximum tolerable crack size within the base or weld regions under about 2.7% applied strain, which is the strain equal to the reeling process. The estimated load-carrying capacity of the plates were found on the safe side with acceptable conservatism for all the SINTAP analysis Levels.

scholarly journals Structural Integrity Assessment of Independent Type-C Cylindrical Tanks Using Finite Element Analysis: Comparative Study Using Stainless Steel and Aluminum Alloy

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1632
Author(s):  
Young-IL Park ◽  
Jin-Seong Cho ◽  
Jeong-Hwan Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Structural Integrity ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Type C ◽  
Materials Used ◽  
Lng Fuel ◽  
Cylindrical Tanks

The International Maritime Organization stipulates that greenhouse gas emissions from ships should be reduced by at least 50% relative to the amount observed in 2008. Consequently, the demand for liquefied natural gas (LNG)-fueled ships has increased significantly. Therefore, an independent type-C cylindrical tank, which is typically applied as an LNG fuel tank, should be investigated. In this study, structural integrity assessments using finite element analysis are performed on C-type LNG fuel tanks for a sea-cleaning vessel. In addition, the applicability of stainless steel and aluminum alloys is evaluated for LNG tank construction. Structural analyses and fatigue limit evaluations, including heat transfer analyses for the tank based on IGC code requirements, are performed, and the results are compared. The results of this study are expected to facilitate the selection of materials used for independent type-C tanks.

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