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Interactions of Lanthanides and Liquid Alkali Metals for “Liquid-Like” Lanthanide Transport in U-Zr Fuel

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Interactions of Lanthanides and Liquid Alkali Metals for “Liquid-Like” Lanthanide Transport in U-Zr Fuel Interactions of Lanthanides and Liquid Alkali Metals for “Liquid-Like” Lanthanide Transport in U-Zr Fuel THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Jeremy Payton Isler Graduate Program in Nuclear Engineering The Ohio State University 2017 Master's Examination Committee: Dr. Jinsuo Zhang, Advisor Dr. Marat Khafizov, Co-Advisor Copyrighted by Jeremy Payton Isler 2017 Abstract One of the major limitations in achieving increased burnup in metallic U-Zr nuclear fuel is Fuel-Cladding Chemical Interaction (FCCI). The migration of the fission product lanthanides from within the fuel to the peripheral is one of the major contributors to FCCI. A “liquid-like” transport mechanism proposes the lanthanide transport is aided by liquid cesium and liquid sodium in the pores of the fuel and at the fuel peripheral. The purpose of this thesis was to provide additional experimental evidence towards this proposed mechanism. This thesis investigated the interaction between the lanthanides and cesium and sodium, with a focus on the solubility of the lanthanides in these liquid alkali metals. First, a prediction of the solubility was calculated using the Miedema model. This prediction was then compared to the inversion crucible solubility experiment performed in this thesis. The solubility experiment studied the temperature and liquid-composition dependence of the lanthanides in liquid sodium, cesium and sodium-cesium mixtures. In addition, the solubility in mixtures shows the various alkali metals concentration effect on the solubility. With the results of differential scanning calorimetry (DSC) experiments, updated phase diagrams for sodium-neodymium and cesium-neodymium were obtained from the experimental data in this thesis. The temperature dependence of neodymium in liquid cesium and the solubility differences in liquid sodium and liquid cesium provide key experimental data towards the theory of ‘liquid-like’ transfer. The greater understanding of the lanthanide transport in the U-Zr ii fuel allows for the fuel to be more efficiently engineered to mitigate FCCI and thus achieve to higher burnups. iii Dedication This document is dedicated to my friends and my family. iv Acknowledgments I would like to thank my advisor, Dr. Jinsuo Zhang, for all his guidance throughout my undergraduate and graduate studies. Not only am I grateful for his guidance but also the myriad of research opportunities he has provided me. I would also like to thank the entire faculty of the NE program. My entire time in the program was a positive one, and I am extremely thankful for all the time and energy they put into my education. I would also like to thank my fellow NE graduate students for all the great memories. I would like to thank the U.S. Department of Energy (DOE) for financially supporting this work. Lastly, but certainly not least, I would like to thank my family for all their support. Their constant support and encouragement of my education has helped to make this milestone in my life achievable. v Vita July 14, 1992 ................................................. Born – Windham, Ohio 2015 ............................................................... B.S. Materials Science and Engineering, The Ohio State University 2015 to present ............................................. Graduate Research Associate, The Ohio State University Publications Isler, J.; Zhang, J. “Examination of Solubility Models for the Determination of Transition Metals within Liquid Alkali Metals.” Metals 2016, 6, 144. Fields of Study Major Field: Nuclear Engineering vi Table of Contents Abstract ............................................................................................................................... ii Dedication .......................................................................................................................... iv Acknowledgments ............................................................................................................... v Vita ..................................................................................................................................... vi Table of Contents .............................................................................................................. vii List of Tables ...................................................................................................................... x List of Figures .................................................................................................................... xi Chapter 1: Introduction ....................................................................................................... 1 1.1 Problem Statement ............................................................................................... 1 1.2 Background and Motivation ...................................................................................... 2 1.2.1 Metallic U-Zr Fuel Development .................................................................. 3 1.2.2 U-Zr Microstructural Transformations ......................................................... 4 1.2.3 Fuel-Cladding Chemical Interaction (FCCI) ................................................ 7 1.2.4 Lanthanide Migration in U-Zr ...................................................................... 8 1.2.5 ‘Liquid-Like’ Transport ................................................................................ 9 vii 1.3 Project Objectives ................................................................................................... 12 Chapter 2: Theory and Literature Review ........................................................................ 13 2.1 Thermodynamic Theory ..................................................................................... 13 2.2 Literature Review of Solubility Experiments ..................................................... 15 2.2.1 Experimental Techniques ............................................................................ 16 2.2.2 Lanthanides and Alkalis Interactions .......................................................... 18 2.3 Miedema Model ................................................................................................. 21 2.3.1 Background ................................................................................................. 21 2.3.2 Model Description ...................................................................................... 22 2.4 Differential Scanning Calorimetry (DSC) .......................................................... 23 2.4.1 Method Background .................................................................................... 23 Chapter 3: Model of Solubility ......................................................................................... 27 3.1 Solubility Calculation ......................................................................................... 27 3.2 Model Comparison to Previous Solubility Experiments .................................... 29 3.3 Model Results for the Lanthanides Solubility .................................................... 35 Chapter 4: Inversion Crucible Solubility Experiment ...................................................... 38 4.1 Experimental Procedure ..................................................................................... 38 4.2 Solubility Results ............................................................................................... 42 4.2.1 Stock Alkali Metal Impurity Concentration ............................................... 43 viii 4.2.2 Time Dependence ....................................................................................... 44 4.2.3 Temperature Dependence ........................................................................... 48 4.2.4 Concentration Dependence ......................................................................... 53 4.2.5 Control Tests in Sodium ............................................................................. 54 Chapter 5: Differential Scanning Calorimetry (DSC) Experiments ................................. 59 5.1 DSC Experimental Technique ............................................................................ 59 5.2 DSC Results ....................................................................................................... 63 5.2.1 Na-Sn .......................................................................................................... 63 5.2.2 Na-Nd .......................................................................................................... 68 5.2.3 Cs-Nd .......................................................................................................... 72 Chapter 6: Conclusion ....................................................................................................... 77 6.1 Summary ............................................................................................................ 77 6.2 Impact on Motivation ......................................................................................... 81 6.3 Recommendations for Future Work ................................................................... 82 References ......................................................................................................................... 83 Appendix A: Experimental Solubility Data ...................................................................... 94 Appendix B: Additional Data of DSC
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