SUBJECT: Ph.D. Proposal Presentation
BY: Kathryn Matlack
TIME: Wednesday, January 16, 2013, 1:00 p.m.
PLACE: Love Building, 210
TITLE: Nonlinear Ultrasound for Radiation Damage Detection in Nuclear Reactor Steel
COMMITTEE: Dr. Laurence Jacobs, Co-Chair (CEE/ME)
Dr. Jianmin Qu, Co-Chair (Northwestern University)
Dr. Jin-Yeon Kim (CEE)
Dr. Chaitanya Deo (NRE)
Dr. David L. McDowell (ME/MSE)
Dr. James Wall (EPRI/ME)


Currently, nuclear power plants provide a substantial amount of energy throughout the US and the world. However, most nuclear reactors in the US have either reached or surpassed their design life limit of typically 40-60 years of operation. There is a need for a nondestructive evaluation (NDE) method to assess the material strength of key components such as the reactor pressure vessel to determine if reactors can continue to operate in safe conditions. Radiation damage produces microstructural features such as point defect clusters, changes in dislocation densities, and precipitates that cause embrittlement and a decrease in the ductility of the material.

The nonlinear ultrasonic technique of second harmonic generation has the ability to monitor microstructural changes in metallic materials. As a monochromatic ultrasonic wave propagates through a material, the interaction of this wave with microstructural features produces a second harmonic wave, and this effect is quantified with the measurable acoustic nonlinearity parameter, β. It is known that β is sensitive to microstructural features such as dislocations, precipitates, and their interactions. These microstructural features have been shown to occur throughout radiation damage in steel material. In this project, nonlinear ultrasonic techniques are used to monitor radiation damage in reactor pressure vessel steel material in efforts of ensuring nuclear power plant sustainability. This project will determine if nonlinear ultrasound is capable of detecting radiation-induced microstructural changes in reactor pressure vessel steel material, and will investigate the relationship between the acoustic nonlinearity parameter and microstructural changes that take place throughout radiation damage.