NSUF 26-5686: High Resolution Thermal Conductivity Study of ATR Irradiated YHx
Yttrium hydride (YHₓ) is a promising material for use in advanced nuclear reactor systems due to its exceptional hydrogen density, favorable neutron moderation characteristics, and thermal stability. However, critical knowledge gaps exist regarding its long-term performance under neutron irradiation, particularly the relationships between irradiation-induced microstructural changes, hydrogen retention, and thermophysical evolution. When exposed to neutron irradiation, YHₓ undergoes structural changes such as defect formation, hydrogen and helium bubble growth, and potential non-stoichiometric transformations. These changes can significantly alter its thermal conductivity, which is critical for optimizing nuclear reactor performance and design.
This project hypothesizes that irradiation in the Advanced Test Reactor (ATR) will create reproducible microstructural features in YHₓ, such as defect clusters, gas bubbles, and grain boundary segregation fields, which will reduce local thermal conductivity due to enhanced phonon scattering. Using the Thermal Conductivity Microscope (TCM), which provides high spatial resolution, localized thermal conductivity measurements will be obtained across irradiated samples. This will allow the identification of thermophysical complexities that are often obscured in bulk measurements.
The project will begin by measuring the thermal conductivity in both as-fabricated YH₂/YH₃ and irradiate YHx samples. Solid-state physics models will then be employed to deconvolute structure-property relationships, providing insights into how irradiation-induced microstructural changes impact thermal transport. Success will be measured by measuring local thermal conductivities, evaluating thermal conductivity trends, and correlating these with microstructural features.
The outcomes of this research will enhance the understanding of structure-property relationships in irradiated YHₓ, inform the design and qualification of irradiation-tolerant hydride components for reactor applications, and provide data to support the development of mechanistic material models under reactor-relevant conditions.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Idaho National Laboratory |
| DOI | 10.46936/NSUF/60017652 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Noé Morales |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | Emma Orcutt |
| PIE Facilities | Irradiated Materials Characterization Laboratory |
| Prep Facilities | Irradiated Materials Characterization Laboratory |
| Project Member | Professor Marat Khafizov, Associate Professor - The Ohio State University (https://orcid.org/0000-0001-8171-3528) |
| Project Member | Dr. Tsvetoslav Pavlov, Distinguished Postdoctoral Associate - Idaho National Laboratory (https://orcid.org/0009-0006-1448-2372) |
| Project Member | Dr. Sobhan Patnaik, Staff Scientist - Idaho National Laboratory (https://orcid.org/0000-0003-2113-828X) |
| Project Member | Mr. Ethan Hisle, Post Irradiation Examination Research Scientist - Idaho National Laboratory (https://orcid.org/0000-0002-9064-6328) |
| Project Member | Mr Mutaz Alshannaq, Research Assistance - The Ohio State University (https://orcid.org/0009-0003-6266-3598) |
| Project Member | Dr. Emma Orcutt, Distinguished Postdoctoral Researcher - Idaho National Laboratory (https://orcid.org/0000-0002-9469-6445) |
| Project Type | RTE |