R5 Procedures for Assessing the High Temperature Response of Structures: Current Status and Future Developments

2007 ◽  
Author(s):  
David W. Dean ◽  
Peter J. Budden ◽  
Robert A. Ainsworth
Keyword(s):  
Power Generation ◽  
Fatigue Crack ◽  
High Temperature ◽  
Fatigue Crack Initiation ◽  
Temperature Response ◽  
Current Status ◽  
Future Developments ◽  
Creep Fatigue ◽  
Creep Fatigue Crack ◽  
The Uk

The R5 procedures have been developed within the UK power generation industry to assess the integrity of nuclear and conventional plant operating at high temperatures. Within R5, there are specific procedures for assessing creep-fatigue crack initiation in initially defect-free components (Volume 2/3) and for assessing components containing defects (Volume 4/5). This paper first describes in outline the current R5 Volume 2/3 and Volume 4/5 procedures. Attention is then focused on recent and proposed future developments in these procedures.

Recent Developments in the R5 Procedures for Assessing the High Temperature Response of Structures

2019 ◽  
Author(s):  
Daniel G. J. Hughes ◽  
Marc Chevalier ◽  
David W. Dean
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Crack Initiation ◽  
High Temperatures ◽  
Fatigue Crack Initiation ◽  
Term Operation ◽  
Creep Fatigue ◽  
Recent Developments ◽  
Creep Fatigue Crack ◽  
The Uk

Abstract The R5 procedures have been developed within the UK power generation industry to assess the integrity of nuclear and conventional plant operating at high temperatures. Within R5, there are specific procedures for assessing creep-fatigue crack initiation in initially defect-free components (Volume 2/3), components containing defects (Volume 4/5), dissimilar metal weldments (Volume 6) and similar metal ferritic weldments under steady loading (Volume 7). A key driver for continued developments in the R5 Procedure is the operational feedback from thirty years of operation of the UK Advanced Gas-Cooled Reactor (AGR) fleet. This experience from operation of the UK AGR fleet can be used to inform the design and operation of future high temperature reactors. Some of the lessons learnt from long-term operation of austenitic stainless steels at high temperatures are detailed briefly within this paper. Further, this paper briefly outlines the current R5 procedures and then focuses on two significant recent developments in these procedures: treatment of carburisation and its impact on creep-fatigue crack initiation and improved methods for predicting creep-fatigue crack growth under combined primary and secondary loads.

Creep-Fatigue Damage and Crack Initiation for a Mod 9Cr-1Mo Structure With Weldments

2007 ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Se-Hwan Lee ◽  
Jong-Bum Kim ◽  
Jae-Han Lee
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Hold Time ◽  
Fatigue Crack Initiation ◽  
Creep Damage ◽  
Steel Specimen ◽  
Structural Test ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

A structural test and evaluation on creep-fatigue damage, and creep-fatigue crack initiation have been carried out for a Mod. 9Cr-1Mo steel structural specimen with weldments. The conservatisms of the design codes of ASME Section III subsection and NH and RCC-MR codes were quantified at the welded joints of Mod.9Cr-1Mo steel and 316L stainless steel with the observed images from the structural test. In creep damage evaluation using the RCC-MR code, isochronous curve has been used rather than directly using the creep law as the RCC-MR specifies. A y-shaped steel specimen of a diameter 500mm, height 440mm and thickness 6.35mm is subjected to creep-fatigue loads with two hours of a hold time at 600°C and a primary nominal stress of 30MPa. The defect assessment procedures of RCC-MR A16 guide do not provide a procedure for Mod.9Cr-1Mo steel yet. In this study application of σd method for the assessment of creep-fatigue crack initiation has been examined for a Mod. 9Cr-1Mo steel structure.

Assessment of Creep and Creep-Fatigue Crack Growth Following the R5 Procedures

2003 ◽  
Author(s):  
R. A. Ainsworth ◽  
P. J. Budden ◽  
D. W. Dean ◽  
M. J. H. Fox ◽  
M. P. O’Donnell ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Single Procedure ◽  
Technical Developments ◽  
Creep Fatigue ◽  
Creep Fatigue Crack ◽  
Assessment Procedures

Parts of the R5 high temperature assessment procedures address creep and creep-fatigue crack growth. The procedures were developed some years ago as separate approaches for creep crack growth (R5 Volume 4) and creep-fatigue crack growth (R5 Volume 5). A major revision to these procedures has recently been completed. This unifies the separate approaches into a single procedure for creep-fatigue crack growth (R5 Volume 4/5). The revision restructures the procedure for easier application and includes a number of technical developments, including criteria for deciding when creep-fatigue interactions are important. This paper describes in outline the new R5 creep-fatigue crack growth procedure.

Creep-Fatigue Crack Initiation Assessments of an Instrument Guide Tube Within a Superheater Header

2014 ◽  
Author(s):  
Jinhua Shi ◽  
Hassam Dodia
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Fatigue Damage ◽  
Material Properties ◽  
Fatigue Crack Initiation ◽  
Guide Tube ◽  
New Approach ◽  
Weld Material ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

In order to extend the boiler lives at Advanced Gas-Cooled Reactor (AGR) nuclear power stations in the UK, new temperature measuring instrumentation to monitor reactor gas temperature has been proposed to install on the bore of an intact boiler tube to provide additional boiler operating data to support the station lifetime extension. This paper details a creep-fatigue crack initiation assessment of the proposed installation of an instrument guide tube within the superheater header using the latest R5 high temperature assessment procedures based on detailed finite element thermal transient stress analysis values for a bounding start-up and shutdown cycle. The fatigue damage at welds has been calculated based on both weld and parent material properties. The new approach for assessing weldments has been used in this paper. This new approach involves splitting the existing Fatigue Strength Reduction Factor (FSRF) into a Weldment Endurance Reduction (WER), which accounts for reduced fatigue endurance due to weld imperfections, and a Weldment Strain Enhacement Factor (WSEF), which accounts for material mismatch and local geometry. The creep assessments of the weld material locations have been carried out on both parent and weld material properties including the welding residual stress. The total creep-fatigue damage is then obtained as the sum of fatigue damage, Df, and creep damage, Dc.

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