Date of Award:

5-2013

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Mechanical and Aerospace Engineering

Committee Chair(s)

Heng Ban

Committee

Heng Ban

Committee

Byard Wood

Committee

Leijun Li

Committee

Steven Folkman

Committee

David Hurley

Abstract

In nuclear reactors, the thermal energy generated from the nuclear reactions needs to be transferred all the way through the core of the fuels to the surrounding steam to be utilized. Therefore, thermal conductivity is considered an important thermophysical property of the fuel which needs to be measured. The nuclear fuel microstructure is known to be damaged by neutronirradiation, which can result in sharp, local changes of thermal conductivity. However, most existing thermal conductivity measurement techniques of nuclear fuel are not able to make high spatial-resolution measurements. The objective of this study was to develop a non-contact thermal conductivity measurement technique to provide micron-sized spatial-resolution capability.

In this study, two lasers are involved for the non-contact feature: one for heating and the other one for detection. A detailed parametric study is performed to optimize measurement conditions analytically and numerically. The numerical work was performed using a finite element model developed in COMSOL Multiphysics. The measurement system was validated using two calibration samples. Sources of experimental errors are discussed qualitatively and quantitatively.

An extended application of the laser-involved technique is explored to measure mechanical properties of solid materials. By measuring the natural frequencies of a cantilever beam, the elasticity constants of the material can be obtained.

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5ae50bddf4549d354036c5369517813f

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