scholarly journals Crack Growth Rate Testing of Bolt-Load Compact Tension Specimens Under Chloride-Induced Stress Corrosion Cracking Conditions in Spent Nuclear Fuel Canisters

2018 ◽  
Author(s):  
Andrew J. Duncan ◽  
Poh-Sang Lam ◽  
Robert L. Sindelar ◽  
Kathryn E. Metzger
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Relative Humidity ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Spent Nuclear Fuel ◽  
Compact Tension ◽  
Corrosion Cracking ◽  
Sea Salt ◽  
Induced Stress

Stress corrosion cracking (SCC) may occur when chloride-bearing salts and/or dust deliquesce on the external surface of the spent nuclear fuel (SNF) canister at weld residual stress regions. An SCC growth rate test is developed using instrumented bolt-load compact tension specimens (ASTM E1681) with experimental apparatus that allows an initially dried salt to deliquesce and infuse naturally to the crack front under temperature and humidity parameters relevant to the canister storage environmental conditions. Characterization of initial shakedown tests was performed to determine a more extensive matrix of testing to provide bounding conditions in which cracking will occur. The test specimen and apparatus designs were modified to enhance the interaction between the deliquescing salt and the crack front for more accurate crack growth rate measurement as a function of stress intensity factor, temperature and relative humidity which is an essential input to the determination of in service inspection frequency of SNF canisters. Testing was conducted over a range of relative humidity controlled by the guidance in ASTM E104 from ambient temperature to 50 °C with salt assemblages of ASTM simulated sea salt. After three months exposure in prototypic dried sea salt, the specimens will be examined for evidence of chloride-induced stress corrosion cracking (CISCC) and observations are reported for a range of relative humidity and temperature conditions. The above testing attempts to provide a technical basis for the boiler pressure vessel (BPV) Section XI code case N-860.

scholarly journals Crack Growth Rate Testing With Instrumented Bolt-Load Compact Tension Specimens Under Chloride-Induced Stress Corrosion Cracking Conditions in Spent Nuclear Fuel Canisters

2017 ◽  
Author(s):  
Andrew J. Duncan ◽  
Poh-Sang Lam ◽  
Robert L. Sindelar ◽  
Joe T. Carter
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Crack Front ◽  
Spent Nuclear Fuel ◽  
Compact Tension ◽  
Corrosion Cracking ◽  
Induced Stress

Stress corrosion cracking (SCC) may occur when chloride-bearing salts and/or dust deliquesce on the external surface of the spent nuclear fuel (SNF) canister at weld residual stress regions. An SCC growth rate test is developed using instrumented bolt-load compact tension specimens using the American Society for Testing Materials (ASTM) specification E1681 with an experimental apparatus that allows an initially dried salt to deliquesce and infuse naturally to the crack front under temperature and humidity parameters relevant to the canister storage environmental conditions. The shakedown tests were conducted over a range of relative humidity controlled by the guidance in ASTM E104 at 50 °C with salt assemblages of (1) mixture of artificial dust and deliquescent salts (2) a mixture of artificial dust and salt from dehydrated sea water. After five months exposure the specimens were examined for evidence of chloride induced stress corrosion cracking (CISCC) and observations are reported for both salt/dust mixtures. The test specimen and apparatus designs will be modified to enhance the interaction between the deliquescing salt and the crack front for more accurate characterization of the crack growth rate as a function of stress intensity factor, which is an essential input to the determination of in-service inspection frequency of SNF canisters.

Crack Growth Rate Testing and Large Plate Demonstration Under Chloride-Induced Stress Corrosion Cracking Conditions in Stainless Steel Canisters for Storage of Spent Nuclear Fuel

2019 ◽  
Author(s):  
Poh-Sang Lam ◽  
Andrew J. Duncan ◽  
Lisa N. Ward ◽  
Robert L. Sindelar ◽  
Yun-Jae Kim ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Crack Growth Rate ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Nuclear Fuel ◽  
Stress Corrosion Cracking ◽  
Spent Nuclear Fuel ◽  
Compact Tension ◽  
Corrosion Cracking

Abstract Stress corrosion cracking may occur when chloride-bearing salts deposit and deliquesce on the external surface of stainless steel spent nuclear fuel storage canisters at weld regions with high residual stresses. Although it has not yet been observed, this phenomenon leads to a confinement concern for these canisters due to its potential for radioactive materials breaching through the containment system boundary provided by the canister wall during extended storage. The tests for crack growth rate have been conducted on bolt-load compact tension specimens in a setup designed to allow initially dried salt deposits to deliquesce and infuse to the crack front under conditions relevant to the canister storage environments (e.g., temperature and humidity). The test and characterization protocols are performed to provide bounding conditions in which cracking will occur. The results after 2- and 6-month exposure are examined in relation to previous studies in condensed brine and compared with other experimental data in the open literature. The knowledge gained from bolt-load compact tension testing is being applied to a large plate cut from a mockup commercial spent nuclear fuel canister to demonstrate the crack growth behavior induced from starter cracks machined in regions where the welding residual stress is expected. All these tests are conducted to support the technical basis for ASME Boiler and Pressure Vessel Section XI Code Case N-860.

Towards a more Realistic Experimental Protocol for the Study of Atmospheric Chloride-Induced Stress Corrosion Cracking in Intermediate Level Radioactive Waste Container Materials

2014 ◽  
Vol 1665 ◽  
pp. 225-230 ◽  
Author(s):  
A.B. Cook ◽  
B. Gu ◽  
S.B. Lyon ◽  
R.C. Newman ◽  
D.L. Engelberg
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Sea Salt ◽  
Induced Stress ◽  
Waste Container ◽  
Deposition Density ◽  
Average Crack ◽  
Intermediate Level Radioactive Waste ◽  
Chloride Deposition

ABSTRACTThe occurrence of Atmospheric chloride-Induced Stress Corrosion Cracking (AISCC) under wetted deposits of MgCl2 or sea-salt at 70°C has been investigated at various Relative Humidities (RH). The appearance of AISCC is a function of the environmental RH. At 33% RH (the deliquescence point of MgCl2), AISCC generated under MgCl2 or sea-salt deposits is of a similar appearance with regards to the number of cracks produced and average crack length. At 50% RH sea-salt seems to be more aggressive at least in terms of crack frequency. This observation may highlight the significance of carnallite (KMgCl3.6H2O) in promoting AISCC in types 304L and 316L stainless steels. The use of accelerated testing methods to validate apparent thresholds in chloride deposition density and other critical factors that influence the initiation and propagation of AISCC is briefly discussed.

scholarly journals The Application of Reliability-Based Design Factors in Stress Corrosion Cracking Evaluations

2002 ◽  
Author(s):  
Edward Friedman
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Initiation ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Initiation Time ◽  
Reliability Based Design ◽  
Design Factors

First-order reliability methodology (FORM) is used to develop reliability-based design factors for deterministic analyses of stress corrosion cracking. The basic elements of FORM as applied to structural reliability problems are reviewed and then employed specifically to stress corrosion cracking evaluations. Failure due to stress corrosion cracking is defined as crack initiation followed by crack growth to a critical depth. The stress corrosion cracking process is thus represented in terms of a crack initiation time model and a crack growth rate model, with the crack growth rate integrated from the initiation time to the time at which the crack grows to its critical depth. Both models are described by log-normal statistical distribution functions. A procedure is developed to evaluate design factors that are applied to the mean values of the crack initiation time and the crack growth rate for specified temperature and stress conditions. The design factors, which depend on the standard deviations of the statistical distributions, are related to a target reliability, which is inversely related to an acceptable probability of failure. The design factors are not fixed, but are evaluated on a case-to-case basis for each application. The use of these design factors in a deterministic analysis assures that the target reliability will be attained and the corresponding acceptable probability of failure will not be exceeded. An example problem illustrates use of this procedure.

Atmospheric Stress Corrosion Cracking of Stainless Steel Rock Climbing Anchors, Part 2: Laboratory Experiments

CORROSION ◽  
10.5006/3242 ◽  
2019 ◽  
Vol 75 (11) ◽  
pp. 1371-1382 ◽  
Author(s):  
Tomáš Prošek ◽  
Jiří Lieberzeit ◽  
Alan Jarvis ◽  
Lionel Kiener
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Crack Growth Rate ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Rock Climbing ◽  
Corrosion Cracking ◽  
Critical Parameters ◽  
Electrolyte Ph

Atmospherically-induced stress corrosion cracking (AISCC) in the presence of chloride deposits has been responsible for considerable incidents of rock climbing anchors breaking under minimal loads in seaside locations, putting climbers lives at stake. However, to date, failures due to AISCC have only been documented in anchors made of Type 304/304L and similar, and no rigorously documented failures have been shown to occur to Type 316/316L anchors. In order to support preparation of a new standard classifying anchors according to their corrosion resistance, the influence of environmental parameters such as periodic washing of chloride deposits, electrolyte pH, and type of rock on AISCC initiation and crack growth rate was studied in laboratory conditions by exposing U-bent specimens of stainless steel Types 321, 304, and 316L with MgCl2 deposits in air at 40°C to 50°C and at 35% to 45% relative humidity. The type of rock and electrolyte pH were not critical parameters for AISCC. Alkaline conditions only slightly prolonged stable crack initiation period and decreased the crack growth rate. Periodic washing in sufficiently short intervals was capable of significantly retarding or even arresting AISCC. The crack growth rate in Type 316L stainless steel was 2- to 3-fold slower than in the molybdenum-free Types 304 and 321. These last two effects are quite likely responsible for the lack of failures observed in Type 316/316L. In view of the lifetime expectancy of rock climbing anchors and other safety-relevant members, the crack growth rate was unacceptably high in all studied materials and their installation should be avoided in vulnerable seaside regions.

Development of an Apparatus for Chloride Induced Stress Corrosion Cracking Test Using Immersion Method With Constant Displacement Condition

2019 ◽  
Author(s):  
Jae-Yoon Jeong ◽  
Myeong-Woo Lee ◽  
Yun-Jae Kim ◽  
Robert Sindelar ◽  
Andrew Duncan
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Structural Integrity ◽  
Compact Tension ◽  
Corrosion Cracking ◽  
Test Method ◽  
Immersion Method ◽  
Induced Stress ◽  
Displacement Condition ◽  
Constant Displacement

Abstract This paper presents a new test method for assessing chloride induced stress corrosion cracking occurred in metal canisters used for storing spent nuclear fuels. The material applied to experiment is austenitic stainless steel, SS304 similarly used on manufacturing canisters and the experiment is carried out with immersing a compact tension specimen to chloride solution made up with artificial sea salt. Constant displacement condition using bolt tightening is applied to the test and a load is measured as a function of time using a load cell. Five specimens are used for the experiment at temperature of 50 °C for several months and stress intensity factor is calculated through the measured relaxed load and crack length on fractured surface of the specimen. Crack growth rate is presented in terms of test periods and consequently this apparatus suggests a method for evaluating structural integrity of chloride stress corrosion cracking.

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