Flow-Induced Wear in Steam Generator Tubes—Prediction Versus Operational Experience

Abstract

Many nuclear steam generators have accumulated more than 10 effective-full-power-years of operation. Eddy-current inspections revealed that a number of these steam generator tubes, notably those located in high local cross-flow regions, have indications of wear at some support plate elevations after 5 to 10 yr of effective-full-power operations. In the last 5 yr, a number of technical papers on nonlinear tube bundle dynamics has been published to address the effect of tube and support plate interactions. At the same time, test data relating wear and tube wall thickness losses for different material combinations and different support plate geometries became available. Based on the available data in the literature, as well as data obtained in the author’s affiliation, this paper assesses the cumulative tube wall wear after 5, 10, and 15 effective-full-power years of operation of a typical commercial nuclear steam generator, using different wear models. It is hoped that this study will shed some light on the probable mechanism that caused the observed wear in today’s operating nuclear steam generators.

Dreidimensionale numerische Simulation strömungsinduzierter Rohrbündelschwingungen

“…Bei Turbulenzerregung steigen die Amplituden nahezu linear mit der Anströmgeschwindigkeit an, so daß erhöhte Amplituden über Ähnlichkeitsbetrachtungen reduziert werden können. Schäden infolge von Turbulenzerregung bestehen meist in erhöhtem Abrieb an den Lagerstellen im Leitblech [AuY98,Ble79,Ble85,Cha87,Che85,KoP84]. Zur Absicherung ist jedoch die Kenntnis eines Turbulenzspektrums in der betrachteten Konfiguration notwendig [VDI97].…”

Markov stochastic process modeling for evolution of wear depth in steam generator tubes

“…Later, a parameter named as work rate is defined, which relates to local loads and sliding distances based on the energy dissipation. 5 To predict the time history of the maximum wear depth of the tube, the wear coefficient and work rate should be obtained. Large number of research works can be found on the wear coefficient from the view point of material properties.…”

Limit load analyses of helical coiled steam generator tubes with a volumetric flaw

“…Previous studies on SG tube mainly focused on cracks 8 and internal local wall thinning, 9 and relatively few studies have been carried out on material loss or removal phenomena caused by flow-induced vibration (FIV) and contact between tubes and support structures. 10,11 These studies were conducted for traditional components, so axial force, internal pressure or bending moment was only taken into account for typical loading conditions on the SG tubes. The studies, which were related to worn or corroded pipelines, have been applied especially to offshore engineering field.…”