We used a range of advanced microscopy techniques to study the microstructure, nanoscale chemistry, and porosity in zirconium alloys at different stages of oxidation. Samples from both autoclave and in-reactor conditions were available, including ZIRLOTM, Zr-1.0Nb, and Zr-2.5Nb samples with different heat treatments. Scanning transmission electron microscopy (STEM), transmission Kikuchi diffraction (TKD), and automated crystal orientation mapping with TEM were used to study the grain structure and phase distribution. Significant differences in grain morphology were observed between samples oxidized in the autoclave and in-reactor, with shorter, less well-aligned monoclinic grains and more tetragonal grains in the neutron-irradiated samples. A combination of energy-dispersive X-ray mapping in STEM and atom probe tomography analysis of second-phase particles (SPPs) can reveal the main and minor element distributions respectively. Neutron irradiation seems to have little effect on promoting fast oxidation or dissolution of ?-niobium precipitates but encourages the dissolution of iron from Laves-phase precipitates. An electron energy-loss spectroscopy (EELS) analysis of the oxidation state of niobium in ?-niobium SPPs in the oxide revealed the fully oxidized Nb5+ state in SPPs deep into the oxide but Nb2+ in crystalline SPPs near the metal-oxide interface. EELS analysis and automated crystal orientation mapping with TEM revealed Widmanstatten-type suboxide layers in some samples with the hexagonal ZrO structure predicted by ab initio modeling. The combined thickness of the ZrO suboxide and oxygen-saturated layers at the metal-oxide interface correlated well to the instantaneous oxidation rate, suggesting that this oxygen-rich zone is part of the protective oxide that is rate limiting in the transport processes involved in oxidation. Porosity in the oxide had a major influence on the overall rate of oxidation, and there was more porosity in the rapidly oxidizing annealed Zr-1.0Nb alloy than in either the recrystallized alloy or the similar alloy exposed to neutron irradiation.

Annotation The 41 papers of this proceedings volume were first presented at the 13th symposium on Zirconium in the Nuclear Industry held in Annecy, France in June of 2001. Many of the papers are devoted to material related issues, corrosion and hydriding behavior, in-reactor studies, and the behavior and properties of Zr alloys used in storing spent fuel. Some papers report on studies of second phase particles, irradiation creep and growth, and material performance during loss of coolant and reactivity initiated accidents. Annotation copyrighted by Book News, Inc., Portland, OR.

Nuclear Corrosion: Research, Progress and Challenges, part of the "Green Book” series of the EFC, builds upon the foundations of the very first book published in this series in 1989 ("Number 1 - Corrosion in the Nuclear Industry”). This newest volume provides an overview on state-of-the-art research in some of the most important areas of nuclear corrosion. Chapters covered include aging phenomena in light water reactors, reprocessing plants, nuclear waste disposal, and supercritical water and liquid metal systems. This book will be a vital resource for both researchers and engineers working within the nuclear field in both academic and industrial environments. Discusses industry related aspects of materials in nuclear power generation and how these materials react with the environment Provides comprehensive coverage of the topic as written by noted experts in the field Includes coverage of nuclear waste corrosion

This collection presents papers from the 151st Annual Meeting & Exhibition of The Minerals, Metals & Materials Society.