NSUF 26-5663: Probing Hydrogen Embrittlement Mechanisms in Neutron-Irradiated RAFM Steel F82H
A neutron-irradiated (327 °C, 2.14 dpa) F82H Disk Multi-purpose Coupon (DMC) from the Nuclear Fuels and Materials Library (NFML) will be subject to small-scale mechanical testing, hydrogen and helium trapping analysis, and electron microscopy characterization to address a critical knowledge gap regarding hydrogen-defect interactions.
The DMC will be shear punch (SP) tested to produce five disks (3 mm diameter) and load-displacement data for cross-technique validation. Disks will be polished on one side to remove rims created during SP, to reduce thicknesses to ~0.3 mm for improved disk bend testing (DBT), and to produce suitable surfaces for electron microscopy. Four of the disks will be charged with deuterium (distinguishable from background hydrogen), and then two of these disks will be implanted with helium (to provide cavity defects of analysis). The five disks will be assessed using DBT, measuring yield strength, ductility, and fracture toughness with high sensitivity to the polished/implanted surface. The tested disks will be characterized using either thermal desorption spectroscopy or electron microscopy (SEM, EBSD, STEM, EELS).
The proposed work will produce mechanical behavior measurements (e.g., yield, fracture toughness), desorption spectra (e.g., deuterium trapping energies), and electron microscopy data (e.g., deformation-microstructure and deformation-defect interactions images, deuterium distributions around nanoscale features). These results are expected to reveal new insights into (1) the interactions between microstructure (e.g., interfaces, phases), defects (e.g., dislocations, cavities, clusters), deformation (e.g., crack tips), and gases and (2) the resulting embrittlement and fracture mechanisms. The scientific outcome of this project will directly facilitate a broader engineering impact: improved understanding of gas-defect interactions, trapping sites, and the effects of trapping on mechanical behavior in structural materials and claddings will enable material and microstructural designs for safer, longer lived core internals.
The team will produce at least one peer-reviewed journal article based on the proposed work.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Oak Ridge National Laboratory |
| DOI | 10.46936/NSUF/60017657 |
| Embargo End Date | 2028-04-22 |
| Facility Tech Lead | Kory Linton, Noé Morales |
| NSUF Call | FY 2026 RTE 1st Call |
| PI | Calvin Lear |
| PIE Facilities | Irradiated Materials Examination and Testing Facility, Low Activation Materials Design and Analysis Laboratory |
| Prep Facilities | Hot Fuel Examination Facility |
| Project Member | Dr. Caleb Massey, R&D Staff Member - Oak Ridge National Laboratory (https://orcid.org/0000-0003-1093-3958) |
| Project Member | Dr. Weicheng Zhong, R&D staff - Oak Ridge National Laboratory (https://orcid.org/0000-0002-3158-9271) |
| Project Member | Dr. Calvin Lear, R&D Associate - Oak Ridge National Laboratory (https://orcid.org/0000-0003-3854-0160) |
| Project Type | RTE |
| Sample Identifiers | 4452 |