Technical Basis for ASME Section VIII Code Case 2235 on Ultrasonic Examination of Welds in Lieu of Radiography

2000 ◽  
Vol 123 (3) ◽  
pp. 338-345 ◽  
Author(s):  
Mahendra D. Rana ◽  
Owen Hedden ◽  
Dave Cowfer ◽  
Roger Boyce
Keyword(s):  
Fracture Mechanics ◽  
Linear Elastic Fracture Mechanics ◽  
Acceptance Criteria ◽  
Ultrasonic Examination ◽  
Linear Elastic ◽  
Division 1 ◽  
Section Viii ◽  
Elastic Fracture ◽  
Technical Basis ◽  
Division 2

In 1996, Code Case 2235, which allows ultrasonic examination of welds in lieu of radiography for ASME Section VIII Division 1 and Division 2 vessels, was approved by the ASME B&PV Code Committee. This Code Case has been revised to incorporate: 1) a reduction in minimum usable thickness from 4″ (107.6 mm) to 0.5″ (12.7 mm), and 2) flaw acceptance criteria including rules on multiple flaws. A linear elastic fracture mechanics procedure has been used in developing the flaw acceptance criteria. This paper presents the technical basis for Code Case 2235.

Proposal of Revised Flaw Acceptance Criteria for Ultrasonic Examination of Welds in Section VIII Division 3: Part 1

2012 ◽  
Author(s):  
Susumu Terada ◽  
Toshio Yoshida
Keyword(s):  
Fracture Mechanics ◽  
Stress Gradient ◽  
Charpy Impact ◽  
Surface Flaw ◽  
Membrane Stress ◽  
Acceptance Criteria ◽  
Ultrasonic Examination ◽  
Stress Levels ◽  
Section Viii ◽  
Division 2

The current flaw acceptance criteria for ultrasonic examination of welds in Table KE-301-1 and KE-301-2 of ASME Section VIII Division 3 (hereinafter Div.3) are almost similar to Code Case 2235 on ultrasonic examination of welds in lieu of radiography. This code case is based on general membrane stress and Charpy impact values of Section VIII Division 2 (hereinafter Div.2). The stress levels of Div.3 are higher due to lower design margin and larger stress gradient through the thickness due to large wall ratio than those of Div.2, and Charpy impact values requirements of Div.3 are also different from those of Div.2. Therefore, the flaw acceptance criteria on ultrasonic examination of welds for Div.3 should be reviewed. This paper is the first part of a two part paper. It describes the basic idea for review of flaw acceptance criteria in Div.3 and the proposed revised surface flaw acceptance criteria for welds based on fracture mechanics evaluation.

Proposal of Revised Flaw Acceptance Criteria for Ultrasonic Examination of Welds in Section VIII Division 3: Part 2

2012 ◽  
Author(s):  
Susumu Terada ◽  
Toshio Yoshida
Keyword(s):  
Fracture Mechanics ◽  
Stress Gradient ◽  
Charpy Impact ◽  
Membrane Stress ◽  
Acceptance Criteria ◽  
Ultrasonic Examination ◽  
Stress Levels ◽  
Section Viii ◽  
Division 2 ◽  
Design Margin

The current flaw acceptance criteria for ultrasonic examination of welds in Table KE-301-1 and KE-301-2 of ASME Section VIII Division 3 (hereinafter Div.3) are almost similar to Code Case 2235 on ultrasonic examination of welds in lieu of radiography. This code case is based on general membrane stress and Charpy impact values of Section VIII Division 2 (hereinafter Div.2). The stress levels of Div.3 are higher due to lower design margin and larger stress gradient through the thickness due to large wall ratio than those of Div.2, and Charpy impact values requirements of Div.3 are also different from those of Div.2. Therefore, the flaw acceptance criteria on ultrasonic examination of welds for Div.3 should be reviewed. This paper is the second part of a two part paper. It describes the basic idea for review of flaw acceptance criteria in Div.3 and the proposed revised surface and subsurface flaw acceptance criteria for welds based on fracture mechanics evaluation.

Alternative Acceptance Criteria for Flaws in Ferritic Steel Components Operating in the Upper Shelf Temperature Range

2012 ◽  
Author(s):  
H. L. Gustin ◽  
R. C. Cipolla ◽  
S. X. Xu ◽  
D. A. Scarth
Keyword(s):  
Fracture Mechanics ◽  
Ferritic Steel ◽  
Linear Elastic Fracture Mechanics ◽  
Acceptance Criteria ◽  
Temperature Range ◽  
Linear Elastic ◽  
Flaw Tolerance ◽  
Elastic Fracture ◽  
Shelf Temperature ◽  
Reactor Pressure

The flaw evaluation rules for ferritic vessels in IWB-3610, IWB-3620 and Appendix A of ASME Section XI are based on linear elastic fracture mechanics techniques and were developed primarily for the irradiated reactor pressure vessel beltline region and other low temperature carbon and low-alloy steel applications in which the material exhibits limited or no ductility prior to failure. There are situations in which ferritic steel components operate in the upper shelf temperature range and therefore exhibit significant ductility and increased flaw tolerance. Application of linear elastic fracture mechanics techniques to these cases can be very conservative. In order to address flaw evaluation of ferritic materials exhibiting upper shelf toughness and high ductility, the proposed Code Case N-749 of ASME Section XI was developed and is currently under committee review. This proposed Code Case provides alternate acceptance criteria for situations in which the component is operating in the upper shelf temperature range and therefore has adequate ductility to allow the use of elastic-plastic fracture mechanics techniques.

An Investigation of the Adequacy of a Simplified Boundary Integral Equation / Influence Function Equation Linear Elastic Fracture Mechanics Solution for Nozzle Corner Cracking

2011 ◽  
Author(s):  
Daniel Sommerville ◽  
Minghao Qin ◽  
Eric Houston
Keyword(s):  
Fracture Mechanics ◽  
Boundary Integral ◽  
Linear Elastic Fracture Mechanics ◽  
Boiling Water Reactors ◽  
Nozzle Design ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Water Reactors ◽  
Technical Basis ◽  
Reactor Pressure

As plants pursue operation for longer periods (i.e. 60 years) the region of the reactor pressure vessel (RPV) which must be considered as the beltline region for generation of pressure-temperature (P-T) curves and satisfaction of 10CFR50 Appendix G requirements for prevention of brittle fracture has increased in size as the region of the vessel with a cumulative fluence greater than 1E17 n/cm has increased with plant age. In recent years nozzles have been identified as being located inside the beltline region of Boiling Water Reactors (BWRs). Consequently fracture mechanics evaluations of the nozzles in the beltline must be performed when developing beltline P-T curves. This paper evaluates adequacy of an existing simplified method for performing a Linear Elastic Fracture Mechanics (LEFM) analysis of a corner cracked, partial penetration, nozzle present in the beltline region of many BWRs. The nozzle design considered in this paper is representative of the BWR water level instrument nozzle. The results of this investigation are intended to provide a technical basis for the adequacy of the simplified nozzle solution considered in this paper for performing ASME Section XI, Appendix G evaluations of the instrument nozzle design.

Fracture Mechanics Assessment of Hydrogen Storage Vessel

2021 ◽  
Author(s):  
Xiaoliang Jia ◽  
Zhiwei Chen ◽  
Fang Ji
Keyword(s):  
High Pressure ◽  
Fracture Mechanics ◽  
Hydrogen Storage ◽  
High Strength Steel ◽  
High Strength ◽  
Linear Elastic Fracture Mechanics ◽  
Storage Vessel ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Hydrogen Storage Vessel

Abstract High strength steel is usually used in fabrication of hydrogen storage vessel. The fracture toughness of high strength steel will be decreased and the crack sensitivity of the structures will be increased when high strength steels are applied in hydrogen environment with high pressure. Hence, the small cracks on the surface of pressure vessel may grow rapidly then lead to rupture. Therefore, this paper makes a series of research on how to evaluate the 4130X steel hydrogen storage vessel with fracture mechanics. This study is based on the assumption that there is a semi-elliptic crack on internal surface of hydrogen storage vessel. First of all, based on linear elastic fracture mechanics, the stress intensity factors and crack tolerance of 4130X steel hydrogen storage vessel have been calculated by means of finite element method based on interaction integral theory and polynomial-approximated approach from GB/T 34019 Ultra-high pressure vessels. Then, a comparative study has been made from the results of above methods to find out the difference between them. At last, the fatigue life of a 4130X steel hydrogen storage vessel has been predicted based on linear elastic fracture mechanics and Paris formula. The calculation methods and analysis conclusion can be used to direct the design and manufacture of hydrogen storage vessel.

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