Abstract
Modern electron microscopy techniques were used to conduct a thorough study of an irradiated urania fuel pellet microstructure to attempt at an understanding of high burnup structure formation in this material. The fuel was irradiated at low power to high burnups in a light water reactor, proving ideal for this purpose. Examination of grain size and orientation with strict spatial selectivity across the fuel pellet radius allowed for capturing the progression of the restructuring process, from its onset to full completion. Based on this information, the polygonization mechanism was shown to be responsible for restructuring, involving formation of low-angle grain boundaries with their initiation occurring at the original high-angle grain boundaries of the as-fabricated pellet and at the gas bubble-matrix interfaces. The low-angle character of boundaries between the subdivided grains disappeared in the fully developed high burnup structure, likely due to creep deformation in the pellet.
| Original language | English |
|---|---|
| Pages (from-to) | 245-259 |
| Number of pages | 15 |
| Journal | Journal of Nuclear Materials |
| Volume | 509 |
| DOIs | |
| State | Published - Oct 2018 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). The authors are indebted to a multitude of facilities and support personnel at ORNL that enabled fuel specimen handling, preparation and extraction from the hot-cell. Specifically, the assistance of Nicole Griffith, Cory Hayes, Barry Kennedy, Jeremey McKinney, Curtis Maples, Bryan Woody, and Irradiated Fuels Examination Laboratory Staff is gratefully acknowledged. Steven Zinkle and Keith Leonard offered useful technical discussions and advice. M. Nedim Cinbiz, Sarah Finkeldei and Grant Helmreich performed a thorough review of the manuscript. This research was conducted using internal R&D funds at ORNL. This research was performed, in part, using instrumentation (FEI Talos F200X S/TEM) provided by the Department of Energy, Office of Nuclear Energy, Advanced Fuels Campaign and the Nuclear Science User Facilities. The authors are indebted to a multitude of facilities and support personnel at ORNL that enabled fuel specimen handling, preparation and extraction from the hot-cell. Specifically, the assistance of Nicole Griffith, Cory Hayes, Barry Kennedy, Jeremey McKinney, Curtis Maples, Bryan Woody, and Irradiated Fuels Examination Laboratory Staff is gratefully acknowledged. Steven Zinkle and Keith Leonard offered useful technical discussions and advice. M. Nedim Cinbiz, Sarah Finkeldei and Grant Helmreich performed a thorough review of the manuscript. This research was conducted using internal R&D funds at ORNL . This research was performed, in part, using instrumentation ( FEI Talos F200X S/TEM ) provided by the Department of Energy, Office of Nuclear Energy, Advanced Fuels Campaign and the Nuclear Science User Facilities.