Development of a computer program to predict structural integrity against fretting wear of steam generator tubes: PIAT (program for integrity assessment of steam generator tubes)

2013 ◽  
Vol 257 ◽  
pp. 146-154 ◽  
Author(s):  
Chi-Yong Park ◽  
Ki-Wahn Ryu ◽  
Huinam Rhee
Keyword(s):  
Computer Program ◽  
Steam Generator ◽  
Structural Integrity ◽  
Fretting Wear ◽  
Integrity Assessment ◽  
Steam Generator Tubes

Structural Integrity Assessment of Steam Generator Tube by the Use of Heterogeneous Finite Element Method

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Xinjian Duan ◽  
Michael J. Kozluk ◽  
Sandra Pagan ◽  
Brian Mills
Keyword(s):  
Finite Element ◽  
Steam Generator ◽  
Failure Modes ◽  
Structural Integrity ◽  
Fretting Wear ◽  
Defect Depth ◽  
Steam Generator Tube ◽  
Integrity Assessment ◽  
Failure Pressure ◽  
Steam Generator Tubes

Aging steam generator tubes have been experiencing a variety of degradations such as pitting, fretting wear, erosion-corrosion, thinning, cracking, and denting. To assist with steam generator life cycle management, some defect-specific flaw models have been developed from burst pressure testing results. In this work, an alternative approach; heterogeneous finite element model (HFEM), is explored. The HFEM is first validated by comparing the predicted failure modes and failure pressure with experimental measurements of several tubes. Several issues related to the finite element analyses such as temporal convergence, mesh size effect, and the determination of critical failure parameters are detailed. The HFEM is then applied to predict the failure pressure for use in a fitness-for-service condition monitoring assessment of one removed steam generator tube. HFEM not only calculates the correct failure pressure for a variety of defects, but also predicts the correct change of failure mode. The Taguchi experimental design method is also applied to prioritize the flaw dimensions that affect the integrity of degraded steam generator tubes such as the defect length, depth, and width. It has been shown that the defect depth is the dominant parameter controlling the failure pressure. The failure pressure varies almost linearly with defect depth when the defect length is greater than two times the tube diameter. An axial slot specific flaw model is finally developed.

Structural Integrity Assessment of Steam Generator Tubes Using a New EPRI Statistical Approach

2002 ◽  
Author(s):  
Carlos Alexandre de Jesus Miranda ◽  
Miguel Mattar Neto
Keyword(s):  
Steam Generator ◽  
Wall Thickness ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Tube Wall ◽  
New Approach ◽  
Inconel 600 ◽  
Integrity Assessment ◽  
Tube Wall Thickness ◽  
Uniform Tube

A fundamental step in tube plugging management of a Steam Generator (SG), in a Nuclear Power Plant (NPP), is the tube structural integrity evaluation. The degradation of SG tubes may be considered one of the most serious problems found in PWRs operation, mainly when the tube material is the Inconel 600. The first repair criterion was based on the degradation mode where a uniform tube wall thickness corrosion thinning occurred. Thus, a requirement of a maximum depth of 40% of the tube wall thickness was imposed for any type of tube damage. A new approach considers different defects arising from different degradation modes, which comes from the in-service inspections (NDE) and how to consider the involved uncertainties. It is based on experimental results, using statistics to consider the involved uncertainties, to assess structural limits of PWR SG tubes. In any case, the obtained results, critical defect dimensions, are within the regulatory limits. In this paper this new approach will be discussed and it will be applied to two cases (two defects) using typical data of SG tubes of one Westinghouse NPP. The obtained results are compared with ‘historical’ approaches and some comments are addressed from the results and their comparison.

A comparative study on the fretting wear of steam generator tubes in korean power plants

Wear ◽  
2003 ◽  
Vol 255 (7-12) ◽  
pp. 1198-1208 ◽  
Author(s):  
Young-Ho Lee ◽  
Hyung-Kyu Kim ◽  
Hong-Deok Kim ◽  
Chi-Yong Park ◽  
In-Sup Kim
Keyword(s):  
Comparative Study ◽  
Steam Generator ◽  
Power Plants ◽  
Fretting Wear ◽  
Steam Generator Tubes

Progress in studying the fretting wear/corrosion of nuclear steam generator tubes

2020 ◽  
Vol 144 ◽  
pp. 107556 ◽  
Author(s):  
Xianglong Guo ◽  
Ping Lai ◽  
Ling Li ◽  
Lichen Tang ◽  
Lefu Zhang
Keyword(s):  
Steam Generator ◽  
Fretting Wear ◽  
Steam Generator Tubes

Limit Loads for Circumferential Cracks in the Steam Generator Tube under Combined Pressure and Bending Loads

2007 ◽  
Vol 345-346 ◽  
pp. 1357-1360
Author(s):  
Hyun Su Kim ◽  
Tae Eun Jin ◽  
Hong Deok Kim ◽  
Han Sub Chung ◽  
Yoon Suk Chang ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Steam Generator ◽  
Nuclear Power ◽  
Plastic Material ◽  
Material Behavior ◽  
Limit Loads ◽  
Integrity Assessment ◽  
Bending Loads ◽  
Steam Generator Tubes

Steam generator in a nuclear power plant is huge heat exchanger that transfers heat from reactor to make steam to drive turbine-generator. Failure of the steam generator tubes can result in the release of fission products to the secondary side. Therefore, accurate integrity assessment of the cracked steam generator tubes is of great importance for maintaining the safety of the nuclear power plant. This paper provides limit loads for circumferential through-wall cracks in steam generator tubes under combined internal pressure and bending loads. Such limit loads are developed on the basis of three dimensional finite element analyses assuming elastic-perfectly plastic material behavior. As for the crack location, both the top of the tubesheet and U-bend regions are considered. The analysis results can be directly applied to the practical integrity assessment of cracked steam generator tubes, because the comparison between experimental data and FE results shows a very good agreement.

Evaluation of Interaction Effects on Part-Through Cracks in Steam Generator Tubes

2013 ◽  
Author(s):  
Yong-Seok Kang ◽  
Hong-Deok Kim ◽  
Kuk-Hee Lee ◽  
Jai-Hak Park
Keyword(s):  
Steam Generator ◽  
Interaction Effect ◽  
Structural Integrity ◽  
Structural Parameters ◽  
Interaction Effects ◽  
Multiple Cracks ◽  
Performance Limit ◽  
Steam Generator Tubing ◽  
Steam Generator Tubes

Degraded steam generator tubing can affect its safety functions. Therefore, its integrity should be maintained for each degradation form and all detected degradation must be assessed to verify that if adequate integrity is retained. Determination of tube integrity limits includes identifying acceptable structural parameters such as flaw length, depth, and amplitude of signals. If we consider just single-cracked tubes, short and deep flaws are not likely to threaten structural integrity of tubes. But if it has multiple-cracks, we have to consider interaction effects of multiple adjacent cracks on its burst pressure. Because adjacent multiple cracks can be merged due to the crack growth then it can challenge against the structural performance limit. There are some studies on the interaction effects of adjacent cracks. However, existing works on the interaction effect consider only through-wall cracks. No study has been carried out on the interaction effects of part-through cracks. Most cracks existing in real steam generator tubing are not through-wall cracks but part-through cracks. Hence, integrity of part-through cracks is more practical issue than that of through-wall cracks. This paper presents experimental burst test results with steam generator tubing for evaluation of interaction effects with axial oriented two collinear and parallel part-through cracks. The interaction effect between two adjacent cracks disappeared when the distance exceeds about 2 mm.

Plastic Limit Load Solutions for Surface Crack in the Steam Generator Tubes

2005 ◽  
Vol 297-300 ◽  
pp. 1704-1712
Author(s):  
Ouk Sub Lee ◽  
Hyun Su Kim ◽  
Jong Sung Kim ◽  
Tae Eun Jin ◽  
Hong Deok Kim ◽  
...  
Keyword(s):  
Steam Generator ◽  
Safety Margin ◽  
Local Limit ◽  
Limit Load ◽  
Material Behavior ◽  
Surface Cracks ◽  
Steam Generators ◽  
Integrity Assessment ◽  
Global And Local ◽  
Steam Generator Tubes

Operating experience of steam generators has shown that cracks of various morphologies frequently occur in the steam generator tubes. These cracked tubes can stay in service if it is proved that the tubes have sufficient safety margin to preclude the risk of burst and leak. Therefore, integrity assessment using exact limit load solutions is very important for safe operation of the steam generators. This paper provides global and local limit load solutions for surface cracks in the steam generator tubes. Such solutions are developed based on three-dimensional (3-D) finite element analyses assuming elastic-perfectly plastic material behavior. For the crack location, both axial and circumferential surface cracks, and for each case, both external and internal cracks are considered. The resulting global and local limit load solutions are given in polynomial forms, and thus can be simply used in practical integrity assessment of the steam generator tubes, because the comparison between experimental data and FE solutions shows good agreement.

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