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dc.contributor.advisorJacobs, Laurence J.
dc.contributor.authorMatlack, Kathryn H.
dc.date.accessioned2014-06-09T13:13:00Z
dc.date.available2014-06-09T13:13:00Z
dc.date.issued2014-04-01
dc.identifier.urihttp://hdl.handle.net/1853/51965
dc.description.abstractRadiation damage occurs in reactor pressure vessel (RPV) steel, causing microstructural changes such as point defect clusters, interstitial loops, vacancy-solute clusters, and precipitates, that cause material embrittlement. Radiation damage is a crucial concern in the nuclear industry since many nuclear plants throughout the US are entering the first period of life extension and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. The result of extended operation is that the RPV and other components will be exposed to higher levels of neutron radiation than they were originally designed to withstand. There is currently no nondestructive evaluation technique that can unambiguously assess the amount of radiation damage in RPV steels. Nonlinear ultrasound (NLU) is a nondestructive evaluation technique that is sensitive to microstructural features such as dislocations, precipitates, and their interactions in metallic materials. The physical effect monitored by NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave, arising from the interaction of the ultrasonic wave with microstructural features. This effect is quantified with the measurable acoustic nonlinearity parameter, beta. In this work, nonlinear ultrasound is used to characterize radiation damage in reactor pressure vessel steels over a range of fluence levels, irradiation temperatures, and material composition. Experimental results are presented and interpreted with newly developed analytical models that combine different irradiation-induced microstructural contributions to the acoustic nonlinearity parameter.en_US
dc.language.isoen_USen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectNonlinear ultrasounden_US
dc.subjectSecond harmonic generationen_US
dc.subjectNondestructive evaluationen_US
dc.subjectRadiation damageen_US
dc.subjectReactor pressure vessel steelen_US
dc.subject.lcshStructural health monitoring
dc.subject.lcshNondestructive testing
dc.subject.lcshNuclear pressure vessels
dc.titleNonlinear ultrasound for radiation damage detectionen_US
dc.typeDissertationen_US
dc.description.degreePh.D.
dc.contributor.departmentMechanical Engineering
dc.embargo.termsnullen_US
thesis.degree.levelDoctoral
dc.contributor.committeeMemberQu, Jianmin
dc.contributor.committeeMemberKim, Jin-Yeon
dc.contributor.committeeMemberMcDowell, David L.
dc.contributor.committeeMemberDeo, Chaitanya
dc.contributor.committeeMemberWall, James J.


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