NSUF 26-5662: Synchrotron X-ray Diffraction and Computed Tomography of Irradiated TRISO Fuel
This project aims to quantify uranium carbide consumption and spatial phase evolution in irradiated UCO TRISO fuel kernels as a function of burnup and irradiation temperature. Uranium carbide plays a critical role in buffering oxygen potential and mitigating CO formation during irradiation; however, its rate of consumption and spatial uniformity under reactor conditions remain poorly constrained experimentally. In addition, recent results from the Advanced Gas Reactor (AGR) program have demonstrated that irradiation-induced kernel migration can occur in UCO TRISO at sufficiently high burnup and temperature, potentially driving strong compositional gradients that have never been directly measured.
The proposed research will employ high-energy synchrotron X-ray powder diffraction (XRD) and X-ray diffraction computed tomography (XRD-CT) at the NSLS-II XPD beamline (28-ID-2). Approximately 20 intact irradiated UCO TRISO particles will be screened using rapid XRD measurements to quantify bulk kernel phase fractions. A subset of particles exhibiting measurable kernel migration will be selected for XRD-CT to reconstruct spatially resolved phase distributions across the kernel. All samples will be measured non-destructively at room temperature using approved double Kapton tube encapsulation.
If successful, this work will provide the first experimental measurements of uranium carbide consumption as a function of burnup and temperature in irradiated UCO TRISO fuel, as well as the first spatially resolved phase maps of kernels affected by migration. These results will significantly advance the state of knowledge by providing direct benchmarks for thermochemical and fuel performance models (e.g., PARFUME, BISON), which currently rely on limited experimental validation. The anticipated scientific outcome is a quantitative, spatially resolved understanding of UCO kernel phase evolution under irradiation, enabling improved fuel design, reduced uncertainty in carbide loading requirements, and more defensible advanced reactor fuel qualification strategies.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Oak Ridge National Laboratory |
| DOI | 10.46936/NSUF/60017658 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Simerjeet Gill |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | William Cureton |
| PIE Facilities | National Synchrotron Light Source II |
| Project Member | D.r Grant Helmreich - Oak Ridge National Laboratory (https://orcid.org/0000-0003-3046-4394) |
| Project Member | Professor David Sprouster, Assistant Professor - Stony Brook University (https://orcid.org/0000-0002-2689-0721) |
| Project Member | Dr. MEHMET TOPSAKAL, Scientist - Brookhaven National Laboratory (https://orcid.org/0000-0002-7880-0740) |
| Project Member | Dr. William Cureton, Research Scientist - Oak Ridge National Laboratory (https://orcid.org/0000-0003-1976-4150) |
| Project Type | RTE |