Burst pressure estimation equations for steam generator tubes with multiple axial surface cracks

2017 ◽  
Vol 158 ◽  
pp. 59-68 ◽  
Author(s):  
Myeong-Woo Lee ◽  
Ji-Seok Kim ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim
Keyword(s):  
Steam Generator ◽  
Burst Pressure ◽  
Surface Cracks ◽  
Estimation Equations ◽  
Pressure Estimation ◽  
Steam Generator Tubes ◽  
Axial Surface

Development of Burst Pressure Estimation Equations for Steam Generator Tubes With Multiple Axial Surface Crack

2018 ◽  
Author(s):  
Ji-Seok Kim ◽  
Myeong-Woo Lee ◽  
Jin-Weon Kim ◽  
Yun-Jae Kim
Keyword(s):  
Steam Generator ◽  
Surface Crack ◽  
Burst Pressure ◽  
Damage Analysis ◽  
Surface Cracks ◽  
Test Results ◽  
Estimation Equations ◽  
Pressure Estimation ◽  
Steam Generator Tubes ◽  
Axial Surface

In this paper, the burst pressure estimation equations for steam generator tubes with multiple axial surface cracks are proposed based on the local collapse load approach concept. The proposed equations are for a single axial surface crack, two collinear axial surface cracks and two non-aligned axial surface cracks. The proposed equations are validated against experimental tube burst test results and finite element damage analysis for twin cracks. Predicted burst pressures agree well with the experimental results and FE analysis results, suggesting validity of the proposed equations to estimate burst pressures for twin axial surface cracks.

Ductile Failure Simulation to Predict Burst Pressures of Steam Generator Tubes With Multiple Axial Cracks

2013 ◽  
Author(s):  
Han-Sang Lee ◽  
Nak Hyun Kim ◽  
Yun-jae Kim ◽  
Jong Sung Kim ◽  
Jin Weon Kim
Keyword(s):  
Steam Generator ◽  
Stress Reduction ◽  
Damage Model ◽  
Ductile Failure ◽  
Thin Plates ◽  
Alloy 600 ◽  
Surface Cracks ◽  
Failure Simulation ◽  
Steam Generator Tubes ◽  
Axial Surface

This paper a new simple numerical method to predict burst pressures of Alloy 600 steam generator tubes with multiple through-wall cracks, based on the stress-modified fracture strain damage model with stress reduction technique. To validate the new method, simulated results using the proposed method are compared with thirty-on published test data of Alloy 600 thin plates and tubes with single or multiple through-wall cracks. Simulated results showing that predicted loads are within 10% of experimentally-measured ones for all cases considered. Moreover, a parametric study is performed to investigate the interaction effect of two axial surface cracks in Alloy 600 steam generator tubes under internal pressure.

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.

On a Flaw Shape Idealization of Axial Surface Flaws for Structural Integrity Assessment of Steam Generator Tubes

2015 ◽  
Author(s):  
Seung-Hyun Park ◽  
Jae-Boong Choi ◽  
Nam-Su Huh
Keyword(s):  
Steam Generator ◽  
Structural Integrity ◽  
Burst Pressure ◽  
Crack Model ◽  
Primary System ◽  
Term Operation ◽  
Integrity Assessment ◽  
Surface Flaws ◽  
Axial Surface ◽  
Flaw Shape

Nowadays, nuclear power plant (NPP) has become one of the most important energy sources to generate electricity in the world. Steam generator (SG) is a heat exchanger included in primary system of NPP. Alloy 600 MA is widely used for SG tube material and this is well-known as weakness of stress corrosion cracking. In recent year, according to increase the number of long-term operation NPP, many axial surface flaws have been found on SG tube during an in-service inspection. Therefore, many researches have been carried out to maintain structural integrity of SG tube. Commonly, flaw shape needs to be idealized to calculate a burst pressure because detected flaw shape is complicated. In this paper, validation of EPRI’s weakest sub-crack model, one of the well-known flaw idealization rule, is conducted through finite element (FE) analysis. For this, three actual flaws are assumed and these are idealized by using four flaw shape idealization methods; semi-elliptical crack model, rectangular crack model, maximum length with effective depth crack model and weakest sub-crack model. Burst pressure of each model is calculated and compared with burst pressure of actual shape crack model. As a result, if actual flaw is idealized by weakest sub-crack model, it is expected that conservative and efficient structural integrity assessment will be possible.

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