Technical Basis for Code Case N-806, Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench

2012 ◽  
Author(s):  
Robert O. McGill ◽  
Mark A. Moenssens ◽  
George A. Antaki ◽  
Douglas A. Scarth
Keyword(s):  
Ease Of Use ◽  
Nuclear Industry ◽  
Task Group ◽  
Metal Loss ◽  
Buried Pipe ◽  
Acceptance Criteria ◽  
Case Methods ◽  
Evaluation Procedures ◽  
Division 1 ◽  
Technical Basis

This paper presents the technical basis for Code Case N-806, Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-filled Trench – Section XI, Division 1. This Code Case has been prepared in the ASME Section XI Task Group on Evaluation Procedures for Degraded Buried Pipe. It addresses the nuclear industry need for evaluation procedures and acceptance criteria for the disposition of metal loss that may be discovered during the inspection of piping buried in a back-filled trench. This paper provides background discussion, scope of the Code Case, key definitions and a summary of Code Case methods followed by the basis explanation where necessary. It is organized to follow the same structure as the Code Case for ease of use.

Further Improvements to ASME Section XI Code Case N-806 for Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench

2015 ◽  
Author(s):  
Robert O. McGill ◽  
Mark A. Moenssens ◽  
George A. Antaki ◽  
Douglas A. Scarth
Keyword(s):  
Corrosion Rate ◽  
Ease Of Use ◽  
Nuclear Industry ◽  
Task Group ◽  
Metal Loss ◽  
Buried Pipe ◽  
Acceptance Criteria ◽  
Evaluation Procedures ◽  
Technical Basis

ASME Section XI Code Case N-806, for evaluation of metal loss in Class 2 and 3 metallic piping buried in a back-filled trench, was first published in 2012. This Code Case has been prepared by the ASME Section XI Task Group on Evaluation Procedures for Degraded Buried Pipe. The Code Case addresses the nuclear industry need for evaluation procedures and acceptance criteria for the disposition of metal loss that is discovered during the inspection of metallic piping buried in a back-filled trench. A number of additional improvements have been proposed for Code Case N-806. These include expanded guidance for the determination and validation of a corrosion rate and other clarifications to improve ease of use. This paper presents an update of details of the proposed revisions to Code Case N-806 and their technical basis.

Technical Basis for Proposed Revisions to Code Case N-806, Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench

2014 ◽  
Author(s):  
Robert O. McGill ◽  
Mark A. Moenssens ◽  
George A. Antaki ◽  
Douglas A. Scarth
Keyword(s):  
Soil Properties ◽  
Structural Integrity ◽  
Ease Of Use ◽  
Nuclear Industry ◽  
Task Group ◽  
Metal Loss ◽  
Buried Pipe ◽  
Acceptance Criteria ◽  
Evaluation Procedures ◽  
Technical Basis

ASME Section XI Code Case N-806, for evaluation of metal loss in Class 2 and 3 metallic piping buried in a back-filled trench, was published in 2012. This Code Case has been prepared by the ASME Section XI Task Group on Evaluation Procedures for Degraded Buried Pipe. The Code Case addresses the nuclear industry need for evaluation procedures and acceptance criteria for the disposition of metal loss that is discovered during the inspection of metallic piping buried in a back-filled trench. A number of improvements have been proposed for Code Case N-806. These include improvements to the analytical procedures for structural integrity evaluation under soil and surcharge loads. In addition, tables of soil properties and other parameters needed in the evaluation are proposed to be provided to improve ease of use. This paper presents the technical basis for the proposed revision to Code Case N-806.

Further Improvements to ASME Section XI Code Case N-806 in a Proposed Second Revision

2019 ◽  
Author(s):  
Robert O. McGill ◽  
George A. Antaki ◽  
Mark A. Moenssens ◽  
Douglas A. Scarth
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Nuclear Industry ◽  
Metal Loss ◽  
Soil Reaction ◽  
Buried Pipe ◽  
Element Analysis ◽  
Design Factor ◽  
Evaluation Procedures ◽  
Need To Evaluate

Abstract ASME Section XI Code Case N-806, for evaluation of metal loss in Class 2 and 3 metallic piping buried in a backfilled trench, was first published in 2012. This Code Case has been prepared by the ASME Section XI Task Group on Evaluation Procedures for Degraded Buried Pipe. The Code Case addresses the nuclear industry need for evaluation procedures and acceptance criteria for the disposition of metal loss that is discovered during the inspection of metallic piping buried in a back-filled trench. In a second revision of the Code Case, several changes are proposed. First, guidance is provided for analytical evaluation of greater detail including finite element analysis methods. A new nonmandatory appendix is included to provide procedures for the evaluation of soil and surcharge loads using finite element analysis. Next, a second new nonmandatory appendix is provided giving detailed guidance on the evaluation of seismic loads. Finally, the need to evaluate the fatigue life of buried piping subjected to cyclic surface loading is now included and a design factor applied to the modulus of soil reaction is introduced. This paper presents details of the proposed changes to Code Case N-806-1 and their technical basis where applicable.

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.

Technical Basis and Strategy for Consolidation of ASME Boiler and Pressure Vessel Code, Section III, Subsection NC (Class 2) and Subsection ND (Class 3) Into a Single Subsection

2019 ◽  
Author(s):  
Jie Wen ◽  
Robert Keating ◽  
Timothy M. Adams
Keyword(s):  
Pressure Vessel ◽  
Task Group ◽  
Detailed Result ◽  
Code Change ◽  
Component Design ◽  
Division 1 ◽  
The Status ◽  
Code Maintenance ◽  
Technical Basis

Abstract ASME Boiler Pressure Vessel Code, Section III, Division 1, Subsection NC, Class 2 components, and Subsection ND, Class 3 components, have significant technical and administrative similarities. The ASME BPV III Standards Committee has a long-standing goal of combining these two subsections (NC and ND). Consolidating Subsections NC and ND will simplify, reduce repetitions and make the Code easier to use. Additionally, a combined Subsection NC/ND will simplify Code maintenance. To facilitate this consolidation, the Subgroup on Component Design, under the BPV III Standards Committee assigned a Task Group to develop a strategy to combine the two subsections into a single subsection while maintaining both Class 2 and Class 3 as separate classes of construction. Both Subsections NC and ND of the Code have been completely reviewed, compared and the technical bases for the differences have been established. The conclusion of this review is that there are only a few major technical differences between the two code class rules; however, there are a significant number of editorial differences. Based on the review, the Task Group developed a strategy that completes the consolidation within two publishing cycles of Code edition. For the Code Edition 2019, two separate Subsections NC and ND books will be published to resolve editorial differences and otherwise align the two subsections. For the Code Edition 2021, a single merged subsection will be published. This paper provides the background for the proposed code change, discusses the detailed result of the NC/ND comparison, and provides the basis for the major technical differences. The paper will also update the status of the project and code actions needed to consolidate to a single subsection.

Technical Basis for Revisions to ASME Section XI Code Case N-597-2 on Requirements for Analytical Evaluation of Pipe Wall Thinning

2015 ◽  
Author(s):  
Douglas A. Scarth ◽  
Michael Davis ◽  
Phil Rush ◽  
Steven X. Xu
Keyword(s):  
Nuclear Regulatory Commission ◽  
Pressure Vessels ◽  
Acceptance Criteria ◽  
Accelerated Corrosion ◽  
Evaluation Procedures ◽  
Technical Requirements ◽  
Wall Thinning ◽  
Regulatory Commission ◽  
Technical Basis ◽  
Flow Accelerated Corrosion

Code Case N-597-2 provides procedures and acceptance criteria for the evaluation of piping items subjected to wall thinning mechanisms such as flow-accelerated corrosion (FAC). The acceptance criteria ensure that margins equivalent to those of the ASME B&PV Code are maintained. Subsequent to the publication of Code Case N-597-2, the U.S. Nuclear Regulatory Commission (NRC) found the Code Case conditionally acceptable. A number of task items have been undertaken by the ASME Section XI Working Group on Pipe Flaw Evaluation (WGPFE) to address the NRC conditions. A 2006 ASME Pressure Vessels and Piping (PVP) Division conference paper was published to provide an expanded explanation of the technical basis for Code Case N-597-2. A 2009 PVP paper was published to provide results of validation of evaluation procedures and acceptance criteria in Code Case N-597-2 against experimental and historic wall thinning events. More recently, revisions to Code Case N-597-2 have been made and were proposed as N-597-3. Significant changes have been made in the proposed revised Code Case to clarify the technical requirements and address the NRC concerns over N-597-2. The technical basis for revising Code Case N-597-2 is provided in this paper.

A Tiered Approach to Girth Weld Defect Acceptance Criteria for Stress-Based Design of Pipelines

2006 ◽  
Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
David Horsley ◽  
Gery Bauman
Keyword(s):  
Test Data ◽  
Plastic Collapse ◽  
Department Of Transportation ◽  
Acceptance Criteria ◽  
Weld Defect ◽  
The Us ◽  
Welding Procedure ◽  
Assessment Procedures ◽  
Technical Basis ◽  
New Procedures

Alternative girth weld defect acceptance criteria implemented in major international codes and standards vary significantly. The requirements for welding procedure qualification and the allowable defect size are often very different among the codes and standards. The assessment procedures in some of the codes and standards are more adaptive to modern micro-alloyed TMCP steels, while others are much less so as they are empirical correlations of test data available at the time of the standards creation. A major effort funded jointly by the US Department of Transportation and PRCI has produced a comprehensive update to the girth weld defect acceptance criteria. The newly proposed procedures have two options. Option 1 is given in an easy-to-use graphical format. The determination of allowable flaw size is extremely simple. Option 2 provides more flexibility and generally allows larger flaws than Option 1, at the expense of more complex computations. Option 1 also has higher fracture toughness requirements than Option 2, as it is built on the concept of plastic collapse. In comparison to some existing codes and standards, the new procedures (1) provide more consistent level of conservatism, (2) include both plastic collapse and fracture criteria, and (3) give necessary considerations to the most frequently occurring defects in modern pipeline constructions. This paper provides an overview of the technical basis of the new procedures and validation against experimental test data.

Technical Basis for Application of Collapse Moments for Locally Thinned Pipes Subjected to Torsion and Bending Proposed for ASME Section XI

2014 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong H. Hoang ◽  
Howard J. Rathbun
Keyword(s):  
Power Plants ◽  
Bending Moments ◽  
Finite Element Analyses ◽  
Pure Bending ◽  
Plastic Bending ◽  
Evaluation Procedures ◽  
Wall Thinning ◽  
Applicable Range ◽  
Technical Basis ◽  
Local Wall Thinning

Piping components in power plants may experience combined bending and torsion moments during operation. There is a lack of guidance for pipe evaluation for pipes with local wall thinning flaws under the combined bending and torsion moments. ASME B&PV Code Section XI Working Group is currently developing fully plastic bending pipe evaluation procedures for pressurized piping components containing local wall thinning subjected to combined torsion and bending moments. Using elastic fully plastic finite element analyses, plastic collapse bending moments under torsions were obtained for 4 (114.3) to 24 (609.6) inch (mm) diameter pipes with various local wall thinning flaw sizes. The objective of this paper is to introduce an equivalent moment, which combines torsion and bending moments by a vector summation, and to establish the applicable range of wall thinning lengths, angles and depths, where the equivalent moments are equal to pure bending moments.

scholarly journals Application of deflection bowl parameters for assessing different structures of road pavement

2018 ◽  
Vol 195 ◽  
pp. 04002
Author(s):  
Bagus Hario Setiadji
Keyword(s):  
Careful Consideration ◽  
Ease Of Use ◽  
Popular Method ◽  
The Road ◽  
Road Pavement ◽  
Evaluation Procedures ◽  
Layer Characteristic ◽  
Subgrade Modulus ◽  
Pavement Structures ◽  
Structural Layer

To date, non-destruction testing (NDT) method is the most popular method to assess the condition of road pavement. Among all evaluation procedures of the NDT method, load-deflection backcalculation analysis is one that is developed widely to understand the structural behavior of road pavement. On one side, the use of this analysis is greatly beneficial for presenting the layer characteristic accurately. However, the analysis requires specialist expertise. To overcome this, deflection bowl parameter application could become one alternative. The parameters are very easy to use; however, the intention of the parameters so far is only as an indication of the condition of the structural layer of the road pavement. Therefore, the parameters have to be used with careful consideration. In this study, the parameters were evaluated to determine the optimal usage of the parameters against different structures of road pavements. The results showed that a simplification of the number of parameters and a reformulation of the parameters were required by taking into account the ease of use in practice, the accuracy of subgrade modulus determination and the possibility to evaluate pavement structures with a layer number less than four.

Derivation of the New Pressurized Thermal Shock Screening Criteria

2011 ◽  
Author(s):  
Terry Dickson ◽  
Shengjun Yin ◽  
Mark Kirk ◽  
Hsuing-Wei Chou
Keyword(s):  
United States ◽  
Fracture Mechanics ◽  
Thermal Shock ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Nuclear Industry ◽  
Screening Criteria ◽  
Pressurized Thermal Shock ◽  
Regulatory Commission ◽  
Technical Basis

As a result of a multi-year, multi-disciplinary effort on the part of the United States Nuclear Regulatory Commission (USNRC), its contractors, and the nuclear industry, a technical basis has been established to support a risk-informed revision to pressurized thermal shock (PTS) regulations originally promulgated in the mid-1980s. The revised regulations provide alternative (optional) reference-temperature (RT)-based screening criteria, which is codified in 10 CFR 50.61(a). How the revised screening criteria were determined from the results of the probabilistic fracture mechanics (PFM) analyses will be discussed in this paper.

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