Abstract
The development of microreactor technology presents an efficient solution for providing portable electricity, catering to both human space exploration needs within our solar system and supplying power to remote Earth-bound areas. The miniaturization of nuclear reactors poses immediate new challenges for materials science with respect to the capability for controlling nuclear reactions via thermalization of highly-energetic neutrons. In a microreactor, neutron moderation takes place in compact geometries, thus new moderator materials are required to exhibit high moderating power per unit of volume. This challenge is currently being addressed through the development of transition metal hydrides, known for their strong nuclear moderation capability but to date, research on their irradiation response is limited, specifically regarding phase stability, hydrogen in-lattice retention, and their dependence on irradiation temperature and dose. Herein, we present a detailed investigation on the response of yttrium dihydride (YH2) to heavy ion irradiation. The experiments indicate that YH2 is stable up to an irradiation dose of 2 dpa and below 800°C, identified herein as a critical temperature for YH2. Our study detected the nucleation and growth of voids as a function of the irradiation temperature. They were the predominant type of radiation damage present in the microstructure of YH2 that was distinguishable from pre-existing defects in the pristine YH2 samples. Below the critical temperature, no phase transformation (degassing/dehydriding) nor amorphization occurred. Experimental results with concomitant density functional theory calculations allowed us to elaborate and propose new strategies to enhance the metal hydride performance in extreme environments.
| Original language | English |
|---|---|
| Article number | 120333 |
| Journal | Acta Materialia |
| Volume | 280 |
| DOIs | |
| State | Published - Nov 1 2024 |
Funding
Research presented in this article was primarily supported by the Laboratory Directed Research and Development (LDRD, United States) program of Los Alamos National Laboratory (LANL) via a Director's Fellowship to MATunes under project number 20200689PRD2 and title \u201CHighly Ordered Refractory Intermetallics: The ZIA-Phases Project\u201D. MATunes would like to thank Dr. Saryu J. Fensin \u2013 team leader of the quasi-static and dynamic behavior of materials team in the LANL's Materials Physics and Applications Division at Center for Integrated Nanotechnologies (MPA-CINT) \u2013 for providing mentorship, funding and scientific support at the end period of his postdoctoral research fellowship at LANL. MATunes would like to thank Dr. Thomas M. Kremmer \u2013 leader of electron-microscopy at Montanuniversit\u00E4t Leoben (Austria) \u2013 for valuable discussions on lattice spacing error determination in TEM measurements, and also thank Professor Dr. rer. nat. Cl\u00E1udio G. Sch\u00F6n at the University of S\u00E3o Paulo and Professor Dipl.-Ing. Dr. mont. Peter J. Uggowitzer at the ETH Z\u00FCrich for useful discussions on the possible mechanisms of dislocation formation upon hydriding the metal yttrium. MATunes would like to express gratitude to Dr. Kurt Sickafus (MST-8/LANL) for useful discussions on solid-state physics, crystal structures and crystallography. MATunes would like to thank the anonymous reviewers and the editors from Acta Materialia for significantly improving this manuscript during peer review. This work was performed, in part, at the CINT, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. The computational part of this research made use of the resources of the High Performance Computing Center at Idaho National Laboratory, which is supported by the Office of Nuclear Energy of the U.S. DOE and the Nuclear Science User Facilities under contract number DE-AC07-05ID14517. SCV, VKM, EPL, and APS gratefully acknowledge support for the neutron diffraction work from LANL's LDRD, United States program under project number 20190649DI and title \u201CDemonstration of Advanced Experimental and Theoretical Characterization of Hydrogen Dynamics and Associated Behavior in Advanced Reactors\u201D. The neutron diffraction work was performed at the Los Alamos Neutron Science Center (LANSCE), a NNSA User Facility operated for the U.S. DOE by LANL under contract number 89233218CNA000001. LANL, an affirmative action equal opportunity employer, is managed by Triad National Security LLC for the U.S. DOE's NNSA under contract 89233218CNA000001. MATunes, DP and CAK acknowledge minor support from the LDRD, United States project 20220597ECR. Research presented in this article was primarily supported by the Laboratory Directed Research and Development (LDRD) program of Los Alamos National Laboratory primarily via a Director\u2019s Fellowship to MATunes under project number 20200689PRD2. MATunes and CAK acknowledge support from the LDRD program 20220597ECR . This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is managed by Triad National Security LLC for the U.S. Department of Energy\u2019s NNSA under contract 89233218CNA000001. The computational part of this research made use of the resources of the High Performance Computing Center at Idaho National Laboratory, which is supported by the Office of Nuclear Energy of the U.S. Department of Energy and the Nuclear Science User Facilities under Contract No. DE-AC07-05ID14517 . MATunes would like to thank Dr. Thomas M. Kremmer \u2013 leader of electron-microscopy at Montanuniversit\u00E4t Leoben (Austria) \u2013 for valuable discussions on lattice spacing error determination in TEM measurements, and also thank Professor Dr. rer. nat. Cl\u00E1udio G. Sch\u00F6n at the University of S\u00E3o Paulo and Professor Dipl.-Ing. Dr. mont. Peter J. Uggowitzer for useful discussions on the mechanism of dislocation formation upon hydriding the metal yttrium.
Keywords
- Metal hydrides
- Microreactors
- Phase stability
- Radiation damage
- Space materials