Materials Compatibility With Uranium Fluorides at High Temperatures
Materials Compatibility With Uranium Fluorides at High Temperatures

Author: S. Anghaie

Publisher:

Published: 1996

Total Pages: 162

ISBN-13:

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The objective of an ongoing study being conducted by the Innovative Nuclear Space Power and Propulsion Institute (INSPI) at the University of Florida, is to find suitable materials for use in contact with uranium tetrafluoride from approximately 1200 to 3000 C. This temperature range encompasses both the liquid and gas phase of UF4. In this project ceramic materials were investigated which have been used in the fuel of nuclear reactors. These materials, if compatible with UF4, would be extremely valuable due to their very high melting temperatures, familiar chemistry, and well characterized nuclear properties. Experiments were conducted on thorium dioxide (ThO2) and uranium dioxide (UO2). Samples were exposed to liquid UF4 at 1100 C and to UF4 vaporized at above 1450 C. Exposures took place in a graphite crucible inside an evacuated quartz tube. An inductive heating system was used to heat the crucible and thereby the UF4. Use of the quartz tube allowed direct observation of the ongoing reactions. At the conclusion of each exposure samples of residual gases diluted with nitrogen were run through a gas chromatograph (GC) to determine which gases were released as corrosion products. Subsequent to each experiment remaining samples were weighed then photographed at 2.5x magnification. Power samples of the surface scales and the bulk samples were then prepared for x-ray diffraction analysis (XRD) to determine composition. Data from the GC and XRD were then correlated with equilibrium reaction product data obtained from F*A*C*T to determine the reactions present. Surface analysis of the samples was conducted using Scanning Electron Microscopy (SEM) to examine the scales formed at high magnification and Energy Dispersive X-Ray Spectroscopy (EDS), to qualitatively determine the elements present in various parts of the scales. Experiments with uranium dioxide showed that although UO2 does not react significantly with UF4, it does dissolve in liquid UF4 and apparently suffers from ablation when exposed to UF4 vapor. Thoria did react with UF4 in both the liquid and gas phase exposures, forming a mixture of uranium dioxide and uranium-thorium oxyfluorides.

Comprehensive Nuclear Materials
Comprehensive Nuclear Materials

Author:

Publisher: Elsevier

Published: 2020-07-22

Total Pages: 4871

ISBN-13: 0081028660

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Materials in a nuclear environment are exposed to extreme conditions of radiation, temperature and/or corrosion, and in many cases the combination of these makes the material behavior very different from conventional materials. This is evident for the four major technological challenges the nuclear technology domain is facing currently: (i) long-term operation of existing Generation II nuclear power plants, (ii) the design of the next generation reactors (Generation IV), (iii) the construction of the ITER fusion reactor in Cadarache (France), (iv) and the intermediate and final disposal of nuclear waste. In order to address these challenges, engineers and designers need to know the properties of a wide variety of materials under these conditions and to understand the underlying processes affecting changes in their behavior, in order to assess their performance and to determine the limits of operation. Comprehensive Nuclear Materials, Second Edition, Seven Volume Set provides broad ranging, validated summaries of all the major topics in the field of nuclear material research for fission as well as fusion reactor systems. Attention is given to the fundamental scientific aspects of nuclear materials: fuel and structural materials for fission reactors, waste materials, and materials for fusion reactors. The articles are written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource of information. Most of the chapters from the first Edition have been revised and updated and a significant number of new topics are covered in completely new material. During the ten years between the two editions, the challenge for applications of nuclear materials has been significantly impacted by world events, public awareness, and technological innovation. Materials play a key role as enablers of new technologies, and we trust that this new edition of Comprehensive Nuclear Materials has captured the key recent developments. Critically reviews the major classes and functions of materials, supporting the selection, assessment, validation and engineering of materials in extreme nuclear environments Comprehensive resource for up-to-date and authoritative information which is not always available elsewhere, even in journals Provides an in-depth treatment of materials modeling and simulation, with a specific focus on nuclear issues Serves as an excellent entry point for students and researchers new to the field