Neutron and hard X-ray diffraction studies of the isothermal transformation kinetics in the research reactor fuel candidate U-8 wt%Mo
Exposing uranium-molybdenum alloys (UMo) retained in the γ phase to elevated temperatures leads to transformation reactions during which the γ-UMo phase decomposes into the thermal equilibrium phases, i.e. U2Mo and α-U. Since α-U is not suitable for a nuclear fuel exposed to high burn-up, it is nece...
| Publié dans: | Journal of applied crystallography. - 1998. - 49(2016), Pt 3 vom: 01. Juni, Seite 923-933 |
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| Auteur principal: | |
| Autres auteurs: | , , , , |
| Format: | Article |
| Langue: | English |
| Publié: |
2016
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| Accès à la collection: | Journal of applied crystallography |
| Sujets: | Journal Article X-ray diffraction isothermal transformation kinetics neutron diffraction nuclear fuels uranium uranium–molybdenum alloys |
| Résumé: | Exposing uranium-molybdenum alloys (UMo) retained in the γ phase to elevated temperatures leads to transformation reactions during which the γ-UMo phase decomposes into the thermal equilibrium phases, i.e. U2Mo and α-U. Since α-U is not suitable for a nuclear fuel exposed to high burn-up, it is necessary to retain the γ-UMo phase during the production process of the fuel elements for modern high-performance research reactors. The present work deals with the isothermal transformation kinetics in U-8 wt%Mo alloys for temperatures between 673 and 798 K and annealing durations of up to 48 h. Annealed samples were examined at room temperature using either X-ray or neutron diffraction to determine the phase composition after thermal treatment, and in situ annealing studies disclosed the onset of phase decomposition. While for temperatures of 698 and 673 K the start of decomposition is delayed, for higher temperatures the first signs of transformation are already observable within 3 h of annealing. The typical C-shaped curves in a time-temperature-transformation (TTT) diagram for both the start and the end of phase decomposition could be determined in the observed temperature regime. Therefore, a revised TTT diagram for U-8 wt%Mo between 673 and 798 K and annealing durations of up to 48 h is proposed |
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| Description: | Date Revised 29.09.2020 published: Electronic-eCollection Citation Status PubMed-not-MEDLINE |
| ISSN: | 0021-8898 |