Grain-by-Grain Study of the Mechanisms of Crack Propagation During Iodine Stress Corrosion Cracking of Zircaloy-4

2009 ◽  
pp. 559-559-17 ◽  
Author(s):  
RE Haddad ◽  
AO Dorado
Keyword(s):  
Crack Propagation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking

An Approach to Model Abstraction of Stress Corrosion Cracking Damage in Management of Spent Nuclear Fuel and High-Level Waste

2013 ◽  
Author(s):  
Tae M. Ahn
Keyword(s):  
Crack Propagation ◽  
Stress Corrosion ◽  
Nuclear Fuel ◽  
Stress Corrosion Cracking ◽  
Spent Nuclear Fuel ◽  
Corrosion Cracking ◽  
Propagation Model ◽  
High Level Waste ◽  
Multiple Cracks ◽  
High Level

This paper presents an approach to assess stress corrosion cracking (SCC) damage of a canister for use in confinement management (extended dry storage or geological disposal) of radionuclides from spent nuclear fuel and high-level (radioactive) waste. Localized corrosion, mainly in pitting form and fabrication flaws, were analyzed as a possible precursor to SCC using field/laboratory data. This paper assesses single crack propagation over long time periods and estimates the potential maximum opening area resulting from multiple cracks. This crack propagation model was developed by the Sandia National Laboratories (SNL) for disposal under seismic conditions, and it appears to be conservative with respect to radionuclide releases through the opening area. The SNL model could be applied to the weld and various metals for both management applications. The conservative SNL approach could be used to estimate consequences of radionuclides dispersals, if a canister failed as the confinement barrier.

Characterization of the Crack Propagation in the API X-52 and API X-65 Steels into Cathodic Protection

2009 ◽  
Vol 1242 ◽  
Author(s):  
A. Aguilar ◽  
R. Esparza ◽  
M.A. Gil ◽  
L.F. Cuahutitla ◽  
E. Rubio-Rosas ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Cathodic Protection ◽  
Reference Electrode ◽  
Important Variable ◽  
Corrosion Cracking ◽  
High Concentrations

ABSTRACTCathodic protection has been applied for many years as the best method to prevent the corrosion in systems which transported hydrocarbon pipelines. However, it has found the presence of stress corrosion cracking (SCC) in steel pipelines with high concentrations of carbonates and bicarbonates with pH final (9 to 11). The resistance to the stress corrosion cracking of the API X-52 and API X-65 steels was evaluated on compact modified wedge opening specimens (WOL). The specimens were loaded of 95% of the yield strength. The resistance of crack propagation and the corrosion rate were evaluated with different applied potentials (-850 and -650 mV), this with respect to a saturated copper/copper sulfate reference electrode. The used electrolytes were simulated soils (carbonate-bicarbonate solution). Evidence of crack propagation of the API X-52 and API X-65 steels were carried out by scanning electron microscopy. The obtained result showed susceptibility to SCC on specimens with cathodic protection. The cathodic protection applied (-850 mV vs Cu/CuSO4 electrode) decreases considerably the corrosion rate on the evaluated steels. In this work the loaded stress showed to be a very important variable on the susceptibility to SCC.

An Electrochemical Testing Method for Stress Corrosion Cracking by Separating Crack Anode from Cathode

CORROSION ◽  
1973 ◽  
Vol 29 (2) ◽  
pp. 70-74 ◽  
Author(s):  
TSUGUO SUZUKI ◽  
MINORU YAMABE ◽  
YOSHIHARU KITAMURA
Keyword(s):  
Crack Propagation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Austenitic Stainless Steels ◽  
Electric Circuit ◽  
Chemical Equipment ◽  
Corrosion Cracking ◽  
Time To Failure ◽  
Magnesium Chloride Solution ◽  
Initiation And Propagation

Abstract The initiation and propagation of stress corrosion cracking (SCC) of austenitic stainless steels in boiling 35% magnesium chloride solution, with the pH adjusted to 3.0, were investigated electrochemically by separating the crack anode from the cathode. The dissolution current accompanying crack propagation can be measured, by connecting the anode with the cathode through an external electric circuit, and as a result, the distinction between crack initiation and propagation becomes very clear. The passive-active cell of SCC, simulated by keeping the crack anode potential at the potential of the cathode using a potentiostat, prevents the coupled potential from falling during crack propagation step, accelerates the dissolution of crack anode, and reduces the time to failure. For materials and environments which have low susceptibility to SCC, it can clearly be determined whether SCC occurs or not, by comparing the critical potential for crack propagation, not for initiation, with the corrosion potential of the unstressed steel in the environment concerned. If the former is more active than the latter, SCC can occur. The present method was applied to predict SCC in some chemical equipment, and successful results were obtained.

Flaw Evaluation for PWR and BWR Component Weld Joints Using Advanced FEA Modeling Techniques

2009 ◽  
Author(s):  
T. Hayashi ◽  
S. F. Hankinson ◽  
T. Saito ◽  
C. K. Ng ◽  
W. H. Bamford
Keyword(s):  
Crack Propagation ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Structural Integrity ◽  
Corrosion Cracking ◽  
Water Reactor ◽  
Crack Shape ◽  
Weld Joints ◽  
Flaw Shape

Primary Water Stress Corrosion Cracking (PWSCC) of Pressurized Water Reactor (PWR) primary loop piping/nozzle Dissimilar Metal Weld (DMW) joints and Inter Granular Stress Corrosion Cracking (IGSCC) of Boiling Water Reactor (BWR) weld joints is an ongoing issue in the nuclear power industry. Recent field experiences with PWSCC of various DMW joints in US plants led to the development and application of an Advanced Finite Element Analyses (AFEA) methodology that permits crack propagation with a natural flaw shape. Crack growth and fracture evaluations for both PWR and BWR components are generally performed based on a conservative, idealized crack shape model, e.g. semi-ellipse, rectangle, etc., depending on the geometry of the crack and the component. Conventional evaluation methodologies and/or assumptions of this kind, in some cases may provide excessive conservatisms. The use of natural flaw shape development with crack propagation might provide a more realistic assessment of crack growth and structural integrity. The prime purpose of this study is to demonstrate the conservatism/margins in the conventional “idealized crack shape” methodology. A comparison study of crack growth behavior between the applications of the idealized and natural crack shape methodologies has been performed in order to assess the level of conservatism/margins in the conventional crack growth evaluation methodology and the possible impacts on the structural integrity evaluation for both PWR and BWR components. Comparison studies on the impacts of the differences in crack growth law and loading condition used for crack growth evaluations have been performed as well.

Mechanism of Chloride Stress Corrosion Cracking of Austenitic Stainless Steels

CORROSION ◽  
1969 ◽  
Vol 25 (11) ◽  
pp. 462-472 ◽  
Author(s):  
P. R. RHODES
Keyword(s):  
Stainless Steel ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Hydrogen Evolution ◽  
Stress Corrosion Cracking ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
304 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel

Abstract Electrochemical studies were made in aqueous LiCl, MgCl2, and MgBr2 solutions and in ZnCl2/KCl molten salt to clarify the corrosion reactions related to stress corrosion cracking (SCC) of austenitic stainless steel and to better define environmental variables critical to the occurrence of chloride SCC. Type 304 stainless steel electrodes were employed, with complementary SCC tests made with U-bend Type 304 stainless steel specimens. Several conclusions critical to an understanding of the mechanism of chloride SCC resulted from these investigations: (1) SCC was observed in concentrated MgBr2 solutions, (2) H2O must be present in the electrolyte, as SCC did not occur in dry molten ZnCl2/KCl, and (3) H2 evolution from corroding specimens may be facilitated by anodic polarization. Present studies do not support a model equating crack propagation with stress assisted anodic dissolution. Rather, evidence is presented that hydrogen evolution at the crack tip occurs and is a critical precursor to crack initiation and propagation. A model of SCC requiring hydrogen evolution at the crack tip is proposed, with emphasis being placed on the effect of anodic reactions within the crack in maintaining high acidity near the crack tip. Recent publications suggest that the role of evolved hydrogen in SCC may be related to formation of hydrogen induced martensitic platelets along paths of crack propagation.

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