scholarly journals Evaluation of primary water stress corrosion cracking growth rates by using the extended finite element method

2015 ◽  
Vol 47 (7) ◽  
pp. 895-906 ◽  
Author(s):  
Sung-Jun Lee ◽  
Yoon-Suk Chang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Water Stress ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Growth Rates ◽  
Extended Finite Element Method ◽  
Corrosion Cracking ◽  
Extended Finite Element ◽  
Primary Water

scholarly journals Effect of Material Macrostructural Parameters on Quantitative Stress Corrosion Cracking Plastic Zone Using Extended Finite Element Method in Welded Joints for Light Water Reactor Environment

CORROSION ◽  
10.5006/3498 ◽  
2020 ◽  
Vol 76 (9) ◽  
pp. 826-834
Author(s):  
Rehmat Bashir ◽  
He Xue ◽  
Jianlong Zhang ◽  
Rui Guo ◽  
Nasir Hayat ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Yield Strength ◽  
Plastic Zone ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Extended Finite Element Method ◽  
Alloy 600 ◽  
Extended Finite Element ◽  
Light Water

Alloy 600, a nickel-chromium alloy, has an outstanding corrosion resistance with excellent fabricability and is used in light water reactors at elevated temperatures. The alloy is also being considered for an advanced reactor concept because of its high allowable design strength at the elevated temperature. Alloy 600 is a power hardening material and basic plastic properties of the alloy are changed in the welded zone due to inhomogeneity in weld joints. The extended finite element method (XFEM) is used when the problem of variations invariably in the stress intensity factors (K) at a different instant rate exists. This paper focuses on the effect of variations in macrostructural properties of the alloy on stress corrosion cracking plastic zone ahead of the crack-tip using XFEM. To control the variations in the K, a new technique is also introduced in this research. The results show that the plastic zone is affected by K (increases with the increase of K), yield strength (plastic zone decreases with the increase in yield strength), and hardening exponent “n” (core region increases with the increase of exponent) of the materials. Simulations were performed and results are compared with experimental data.

Mechanical Stress Improvement Process (MSIP) Used to Prevent and Mitigate Primary Water Stress Corrosion Cracking (PWSCC) in Reactor Vessel Piping at V.C. Summer

2003 ◽  
Author(s):  
E. A. Ray ◽  
K. Weir ◽  
C. Rice ◽  
T. Damico
Keyword(s):  
Water Stress ◽  
Stress Corrosion ◽  
Mechanical Stress ◽  
Stress Corrosion Cracking ◽  
Reactor Vessel ◽  
Corrosion Cracking ◽  
The Other ◽  
Water Reactor ◽  
Improvement Process ◽  
Primary Water

During the October 2000 refueling outage at the V.C. Summer Nuclear Station, a leak was discovered in one of the three reactor vessel hot leg nozzle to pipe weld connections. The root cause of this leak was determined to be extensive weld repairs causing high tensile stresses throughout the pipe weld; leading to primary water stress corrosion cracking (PWSCC) of the Alloy 82/182 (Inconel). This nozzle was repaired and V.C. Summer began investigating other mitigative or repair techniques on the other nozzles. During the next refueling outage V.C. Summer took mitigative actions by applying the patented Mechanical Stress Improvement Process (MSIP) to the other hot legs. MSIP contracts the pipe on one side of the weldment, placing the inner region of the weld into compression. This is an effective means to prevent and mitigate PWSCC. Analyses were performed to determine the redistribution of residual stresses, amount of strain in the region of application, reactor coolant piping loads and stresses, and effect on equipment supports. In May 2002, using a newly designed 34-inch clamp, MSIP was successfully applied to the two hot-leg nozzle weldments. The pre- and post-MSIP NDE results were highly favorable. MSIP has been used extensively on piping in boiling water reactor (BWR) plants to successfully prevent and mitigate SCC. This includes Reactor Vessel nozzle piping over 30-inch diameter with 2.3-inch wall thickness similar in both size and materials to piping in pressurized water reactor (PWR) plants such as V.C. Summer. The application of MSIP at V.C. Summer was successfully completed and showed the process to be predictable with no significant changes in the overall operation of the plant. The pre- and post-nondestructive examination of the reactor vessel nozzle weldment showed no detrimental effects on the weldment due to the MSIP.

Weld Residual Stresses and Primary Water Stress Corrosion Cracking in Bimetal Nuclear Pipe Welds

2007 ◽  
Author(s):  
Frederick W. Brust ◽  
Paul M. Scott
Keyword(s):  
Water Stress ◽  
Residual Stresses ◽  
Weld Metal ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Pressure Vessel ◽  
Large Diameter ◽  
Corrosion Cracking ◽  
Primary Water

There have been incidents recently where cracking has been observed in the bi-metallic welds that join the hot leg to the reactor pressure vessel nozzle. The hot leg pipes are typically large diameter, thick wall pipes. Typically, an inconel weld metal is used to join the ferritic pressure vessel steel to the stainless steel pipe. The cracking, mainly confined to the inconel weld metal, is caused by corrosion mechanisms. Tensile weld residual stresses, in addition to service loads, contribute to PWSCC (Primary Water Stress Corrosion Cracking) crack growth. In addition to the large diameter hot leg pipe, cracking in other piping components of different sizes has been observed. For instance, surge lines and spray line cracking has been observed that has been attributed to this degradation mechanism. Here we present some models which are used to predict the PWSCC behavior in nuclear piping. This includes weld model solutions of bimetal pipe welds along with an example calculation of PWSCC crack growth in a hot leg. Risk based considerations are also discussed.

Assessment of primary water stress corrosion cracking of PWR steam generator tubes

1992 ◽  
Vol 134 (2-3) ◽  
pp. 199-215 ◽  
Author(s):  
V.N. Shah ◽  
D.B. Lowenstein ◽  
A.P.L. Turner ◽  
S.R. Ward ◽  
J.A. Gorman ◽  
...  
Keyword(s):  
Water Stress ◽  
Stress Corrosion ◽  
Steam Generator ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Primary Water ◽  
Steam Generator Tubes
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