Steam generator tube integrity program. Phase I report. [PWR]

Alzheimer, J.M.; Clark, Robert A.; Morris, C.J.; Vagins, M.

doi:10.2172/5920767

Cited by 19 publications

(22 citation statements)

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“…The tube of which the defect depth was 70% of the TW showed a ligament rupture at 37 MPa. This pressure is much lower than that of the unflawed tube; 66.9 MPa [6]. Ligament rupture pressures of the tubes with different defect depths and different wrap angles are shown in Fig.…”

Section: Resultsmentioning

confidence: 84%

“…Ligament rupture pressure of axial notch defect machined by an electrodischarge machining (EDM) has been evaluated [3][4][5]. Wastage was another concern with new steam generator, and it was usually found in the region of a low coolant flow and a high heat flux until the late 1970s [6]. After change of the secondary side water chemistry from a phosphate to an all volatile water treatment (AVT) in the early 1980s, the wastage substantially decreased.…”

Section: Introductionmentioning

confidence: 99%

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Rupture pressure of wear degraded alloy 600 steam generator tubings

Hwang

Namgung

Jung

et al. 2008

Journal of Nuclear Materials

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Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Rupture pressure of wear degraded alloy 600 steam generator tubings

Hwang

Namgung

Jung

et al. 2008

Journal of Nuclear Materials

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“…For failure to occurr at MSLB pressure levels a tube must have 80% through-wall uniform thinning over a 1 in. axial length (Alzheimer et al 1979). Thus, inservice tubes with pitting/wastage type defects of limited axial extent would most likely fail by leakage at a deep pit.…”

Section: Results Of Burst Testingmentioning

confidence: 99%

Steam generator group project: Task 13 final report: Nondestructive examination validation

Bradley¹,

Doctor²,

Ferris³

et al. 1988

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The Steam Generator Group Project (SGGP) was a multi-task effort using the retired-from-service Surry 2A pressurized water reactor steam generator as a test bed to investigate the reliability and effectiveness of in-service nondestructive eddy current (EC) inspection equipment and procedures. The information developed provided the technical basis for recommendations for improved in-service inspection and tube plugging criteria of steam generators. This report describes the results and analysis from Task 13-NDE Validation. The primary objective of Task 13 was to validate the EC inspection results obtained under Tasks 7 and 9 and thereby establish the reliability of EC inspection to detect and size tube defects. Additional objectives were to assess the nature and severity of tube degradation from all regions of the generator and to measure the remaining integrity of degraded specimens by burst testing. More than 550 specimens were removed from the generator and included in the validation studies. The bases for selecting the specimens and the methods and procedures used for specimen removal from the generator are reported. Results from metallurgical examinations of these specimens are presented and discussed. These examinations include visual inspection of all specimens to locate and identify tube degradation, metallographic examination of selected specimens to establish defect severity and burst testing of selected specimens to establish the remaining integrity of service-degraded tubes. Statistical analysis of the combined metallurgical and EC data to determine the probability of detection (POD) and sizing accuracy are reported along with a discussion of the factors which influenced the EC results. Finally, listings of the metallurgical and corresponding EC data bases are given.

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“…These tests did not involve many tubes having short deep flaws. 6 In the original analysis the value of the flow stress factor was chosen as k = 0.55, and β was determined to be 0.9. 2 ANL has conducted a number of tests on tubes with short and deep (6. Fig.…”

Section: Updated Values Of β and Kmentioning

confidence: 99%

Validation of failure and leak rate correlations for stress corrosion cracks in steam generator tubes.

Majumdar¹,

Bakhtiari²,

Kasza³

et al. 2002

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This report summarizes models for the prediction of failure pressures and leak rates under normal operation and design-basis accident conditions in steam generator tubes with axial and circumferential cracks. These models were first validated through failure and leak rate tests at room temperature and at 282°C on tubes with rectangular, triangular, and trapezoidal notches fabricated by electrodischarge machining. They were then compared with failure and leak rate tests conducted on tubes with laboratory-generated outer-diameter stress corrosion cracks and steam generator tubes with fieldinduced stress corrosion cracks, which have highly complex morphology. Complex crack profiles are addressed using a model based on the concept of equivalent rectangular cracks. The predictions of the models are in reasonable agreement with test results, the time-dependent initiation and increase of leak rates observed in some tests cannot be predicted by the model. impact specimen fastened by spot-welded straps to the tube with a 6. 35-mm (0.25-in.) gap between the jet exit and the impact specimen.. Executive SummaryThis report summarizes and validates the models used for predicting failure pressures and leak rates in unrepaired steam generator (SG) tubes with axial and circumferential cracks that developed under normal operation and design-basis accident conditions. Failure and leak rate tests have been conducted on SG tubes with outer diameter (OD), part-throughwall, electrodischarge machined (EDM) notches both at room temperature and at 282°C. Notch length in these tests ranged from 6 mm (0.25 in.) to 38 mm (1.5 in.), and notch depths of 60, 80, and 90% (in addition to 100% throughwall) were tested.Extensive tests on rectangular as well as trapezoidal and triangular part-throughwall flaws were conducted to derive a correlation for predicting ligament rupture pressure of tubes with axial notches, either shallow or deep.A procedure for defining an equivalent rectangular crack for an arbitrarily shaped notch or crack (e.g., ODSCC), based on multiparameter analysis of eddy current data from a rotating pancake coil, has been developed. Structural and leak rate analyses of the flaws and comparison with experimental data have shown that the ligament failure pressure in nonrectangular notches or SCCs can be predicted reasonably well. These predictions were made with a flow stress model that is strictly applicable to rectangular part-throughwall cracks, in which the actual crack profile was replaced by an equivalent rectangular crack.Interaction effects between two or more throughwall notches as influenced by ligaments separating the notches were analyzed by finite element analyses. It was found that for type 4 (staggered) axial notches with two 6-or 13-mm cracks, the ligament width has to be ≥0.8 to 1.1 mm in order for their strength (i.e., unstable burst pressure) to exceed that of notches without the ligament. For type 2 (colinear) notches of similar size, the ligament width has to be greater than 1.8 to 2.5 mm to stren...

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Steam generator tube integrity program. Phase I report. [PWR]

Cited by 19 publications

References 1 publication

Rupture pressure of wear degraded alloy 600 steam generator tubings

Rupture pressure of wear degraded alloy 600 steam generator tubings

Steam generator group project: Task 13 final report: Nondestructive examination validation

Validation of failure and leak rate correlations for stress corrosion cracks in steam generator tubes.

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