Doctoral Dissertations

Keywords and Phrases

Cladding; Corrosion; Irradiation; Nanostructuring; Severe Plastic Deformation; TEM

Abstract

Kanthal D and FeCrAl alloys in general, are prospective candidates as accident tolerant nuclear fuel cladding materials. The work presented herein focuses on applying two techniques of severe plastic deformation, equal channel angular pressing (ECAP) and high-pressure torsion (HPT), as means of grain refinement to improve irradiation resistance. Samples of as-received, ECAP, and HPT processed Kanthal D were exposed to neutron irradiation to a dose of 2 DPA at two different temperatures, 300 °C and 500 °C. Detailed characterization was performed including mechanical and microstructural, and several positive improvements with regards to irradiation resistance were identified in the ECAP and HPT conditions. Work is also presented on how grain refinement through ECAP affects the steam corrosion resistance of Kanthal D. Samples of as-received Kanthal D and ECAP Kanthal D were exposed to steam at 1200 °C for 2 hours. A protective aluminum oxide layer was identified to have formed regardless of grain size after exposure to steam, but the oxide layer was identified to be thinner on the ECAP sample indicating improved corrosion resistance at least in a high temperature steam environment. Zircaloy-4, a zirconium-based alloy, used as a fuel cladding material in past and current generation light water nuclear reactors suffers from the effects of zirconium hydride formation including delayed hydride cracking. Zirconium hydrides in samples of hydrogen charged zircaloy-4 were characterized using 4-dimensional scanning transmission electron microscopy (4D-STEM). With investigation on a novel scale, hydride interactions along with indications of early-stage hydride formation were observed.

Advisor(s)

Wen, Haiming

Committee Member(s)

Chernatynskiy, Aleksandr V.
Hoffman, Andrew
Graham, Joseph T.
O'Malley, Ronald J.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2025

Journal article titles appearing in thesis/dissertation

Paper I, Effect of Grain Refinement on High Temperature Steam Oxidation of an FeCrAl Alloy, found on pages 26–62, has been published in Corrosion Science.

Paper II, Site-specific Nanoscale Characterization of Zirconium Hydrides in the Hydride Rim Structure of Hydrogen-charged Zircaloy-4 Cladding, found on pages 63– 126, has been submitted to Materials Characterization

Paper III, Post Irradiation Behavior and Characterization of Ultra-fine grained and Nanocrystalline FeCrAl after Neutron Irradiation, found on pages 127–171, is intended for submission to Acta Materialia.

Pagination

xiv, 188 pages

Note about bibliography

Includes_bibliographical_references_(pages 180-186)

Rights

© 2025 Joshua Eddy Rittenhouse , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12517

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