Download or read book Assessment of the Mechanical Stress Improvement Process for Mitigating Primary Water Stress Corrosion Cracking in Nickel Alloy Butt Welds in Piping Systems Approved for Leak before break written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Weld Overlays for Mitigating Primary Water Stress Corrosion Cracking at Nickel Alloy Butt Welds in Piping Systems Approved for Leak before break written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation and Evaluation of Stress corrosion Cracking in Piping of Light Water Reactor Plants written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1979 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Stainless Steel Pipe Cracking written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Leaks and cracks in the heat-affected zones of weldments in austenitic stainless steel piping and associated components of boiling water reactors (BWRs) have been observed since the mid-1960s. Since that time, cracking has continued to occur and indications have been found in all parts of the recirculation system, including the largest diameter lines. Proposed solutions include remedies primarily intended to produce a more favorable residual stress state, materials which are more resistant to stress corrosion cracking (SCC), and changes in the reactor environment which decrease the susceptibility to cracking. In addition to evaluating these remedies, it is also important to gain a better understanding of key variables such as residual stresses, crack growth rates, and the leak-before-break margin in flawed piping, which may impact regulatory decisions on operating plants. The main areas of effort during the past year have been (1) studies of impurity effects on susceptibility to intergranular stress corrosion cracking (IGSCC), (2) crack growth rate measurements, (3) finite-element studies of residual stress produced by induction heating stress improvement (IHSI) and the addition of weld overlays to flawed piping, (4) leak-before-break analyses of piping with 360° part-through cracks, and (5) parametric studies on the effect of through-wall residual stresses on IGSCC crack growth behavior in large-diameter piping weldments. 5 references, 15 figures, 2 tables.
Download or read book A Metallurgical Evaluation of Stress Corrosion Cracking in Large Diameter Stainless Steel Piping written by and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrasonic testing (UT) of the stainless steel piping in the primary coolant water system of SRS reactors indicates the presence of short, partly-through-wall stress corrosion cracks in the heat-affected zone of approximately 7% of the circumferential pipe welds. These cracks are thought to develop by intergranular nucleation and mixed mode propagation. Metallographic evaluations have confirmed the UT indications of crack size and provided evidence that crack growth involved the accumulation of chloride inside the growing crack. It is postulated that the development of an oxygen depletion cell inside the crack results in the migration of chloride ions to the crack tip to balance the accumulation of positively charged metallic ions. The results of this metallurgicial evaluation, combined with structural assessments of system integrity, support the existence of leak-before-break conditions in the SRS reactor piping system. 13 refs., 9 figs.
Download or read book Primary Water Stress Corrosion Cracking of High chromium Nickel base Welds Near Dissimilar Metal Weld Interfaces written by B. Alexandreanu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Primary Water Stress Corrosion Cracking of Alloy 600 written by and published by . This book was released on 1993 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Correlations of stress corrosion cracking (SCC) data in deaerated water with temperature, stress, metallography, and processing for laboratory test specimens are presented. Initiation time data show that a low temperature anneal and resulting absence of grain boundary carbides result in a material having increased susceptibility to SCC. Data also show that hot worked and annealed Alloy 600 is more resistant than cold worked and annealed material, both having carbide decorated grain boundaries. In absence of grain boundary carbides, both materials are equally susceptible. Low temperature thermal treatment (1100F) reduces SCC susceptibility with or without grain boundary decoration. Weld metal data and data correlations developed from 700 double U-bends are presented. Data demonstrate the effect of increased carbon content to improve SCC resistance. The data shows that the general relation of time, temperature and strain for wrought material is followed for the weld metal. The weld process used did not affect the SCC susceptibility of EN-82 which showed a greater resistance to SCC than EN-62. Stress relief of weld deposits showed an improvement for wrought material. Heat affected zone resistance was improved if the starting material received a high temperature anneal (1850 to 2000F). Range of SCC initiation times for weld metal is comparable to the range of initiation times for wrought material.
Download or read book Applicability of Cold Metal Transfer for Repair of Dissimilar Metal Welds in Stainless Steel Piping in Nuclear Power Plants written by Thomas Walker Daniels and published by . This book was released on 2015 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion resistant butt welds in nuclear coolant loop piping were made with the Ni-base alloy 600 family during their initial construction several decades ago. Time has proved this material selection to be inadequate for resisting stress corrosion cracking from the corrosive primary water solution. Continuing damage from primary water stress corrosion cracking (PWSCC) requires welds to be repaired using structural weld overlays (SWOLs) on the outer pipe diameter to prevent through-thickness breaches. In recent years the nuclear power industry has faced challenges with hot cracking when depositing SWOLs using gas-tungsten arc welding (GTAW). The solidification cracking has been linked to high dilution of the high-Cr Ni-base filler metal from the cast stainless steel base metal pipe. This study investigates the low heat input process called cold metal transfer (CMT) as an alternative to GTAW, and its ability to create low-dilution dissimilar metal SWOLs of filler metal 52M on 304L stainless steel. Bead on plate welds were made to simulate SWOLs on nuclear piping. Experimental procedures included a design of experiment (DOE) to optimize CMT overlay parameters, ThermoCalc[trademark] solidification simulations of diluted 52M with 304L stainless steel, compositional quantification of weld transition regions, and ultrasonic evaluation and mechanical testing of a CMT weld overlay mockup. DOE was used to acquire understanding of the CMT process and optimize bead-on-plate overlay parameters with respect to desired weld characteristics, which included low dilution, good surface quality, moderate toe angle, and defect-free welds. DOE was effective in developing predictive empirical models that were then used to target desired weld dilution, surface quality, geometry, and arc power responses. The resulting optimized CMT weld showed responses that fell within, or near ranges for acceptable criteria predicted by empirical equations.
Download or read book Intergranular stress corrosion cracking of Ni Ce Fe Alloy 600 tubes in PWR primary water review and assessment for model development written by Y. S. Garud and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stress Corrosion Cracking in Light Water Reactors written by International Atomic Energy Agency and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides general descriptions of degradation mechanisms of different types of stress corrosion cracking (SCC) which are concerned with systems, structures and components in PWRs and BWRs. This publication includes examples of good practices in preventing, mitigating and repairing SCC damage and summarizes research and development programmes.
Download or read book Stress Corrosion Cracking of Nickel base Alloy Weldments written by D. E. Jordan and published by . This book was released on 1990 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stress Corrosion Cracking Behavior of Nickel base Weldments in Boiling Water Reactor Environments written by John Schisano and published by . This book was released on 1993 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability Analysis of Circumferential Cracks in Reactor Piping Systems written by Hiroshi Tada and published by . This book was released on 1979 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Indications of Stress Corrosion Cracking Resistance in Alloy 82 Dissimilar Metal Welds in Simulated Primary Water Environments written by Suraj Persaud and published by . This book was released on 2011 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Joints between carbon steel and Alloy 600, containing Alloy 82 weld metal, were exposed to two steam-hydrogen environments considered to simulate exposure to primary water conditions in a Pressurized Water Reactor (PWR) or Canada Deuterium Uranium (CANDU) reactor. The welds were found to have elevated and variable iron contents due to dilution by carbon steel during welding. This gave the Alloy 82 weld, near the inner surface of the component, an iron content approaching that of Alloy 800. A potentially protective external iron oxide film formed on the inner surface of the weld. However, the chromium content throughout the weld is below that which would form an external chromium oxide. The results indicate that low chromium content causes internal oxidation throughout the weld and potentially below the external iron oxide which could lead to Primary Water Stress Corrosion Cracking (PWSCC).
Download or read book Prediction of Pure Water Stress Corrosion Cracking PWSCC in Nickel Base Alloys Using Crack Growth Rate Models written by and published by . This book was released on 1995 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ford/Andresen slip dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material condition. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip dissolution mechanism. No voids, hydrides, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxides found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip.
Download or read book NRC Regulatory Guides written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1973 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A compilation of currently available electronic versions of NRC regulatory guides.
Download or read book Evaluation of Stress Corrosion Crack Growth and Allowable Flaw Sizes in an Alloy 82 182 Alloy 600 Dissimilar Metal Butt Weld in a 2 Inch Nozzle written by Thomas E. Demers and published by . This book was released on 2013 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
