Abstract
Understanding compositional and microstructural changes in functional intermetallic coatings is of great importance for fusion energy and nuclear materials applications. Tritium (3H) and lithium (6Li, 7Li) transport within a neutron irradiated target rod employing an aluminide-coated austenitic stainless-steel cladding was investigated using state-of-the-art multimodal imaging. Specifically, a scanning electron microscope augmented with focused ion beam (SEM-FIB) was used to prepare lift-out samples of the irradiated coating for microanalysis. Scanning transmission electron microscopy (STEM) was used to acquire atomic-scale information on the coating surface microstructure, morphology, and composition. Atomic force microscopy (AFM) was used to determine lift-out dimensions nondestructively. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed the presence of carbonaceous species and unexpected lithium isotopic distributions in the irradiated tubing, suggesting light isotope mobility between internal target components during irradiation. SIMS chemical mapping of aluminide coatings at core midplane and lower core locations of the cladding shows that light isotopic (e.g., 3H, 6Li, 7Li) distributions are different in the irradiated coating. Advance correlative imaging results suggest lithium transport during the tritium production process and give new insights into the fundamental transport mechanism within the target during irradiation and non-equilibrium conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 475-483 |
| Number of pages | 9 |
| Journal | Journal of Materials Research and Technology |
| Volume | 14 |
| DOIs | |
| State | Published - Sep 1 2021 |
| Externally published | Yes |
Funding
The authors are grateful for the support from the PNNL Nuclear Processing and Sciences Initiative (NPSI) - Laboratory Directed Research and Development ( LDRD ) fund. The authors would like to thank the Tritium Modernization Program of the Department of Energy's National Nuclear Security Administration, (DOE / NNSA ) for additional support. The authors are indebted to Dr. David Senor for insightful discussions of sample selections and Michael Perkins for graphic support. SEM-FIB and AFM analyses were performed in the Radiological Microscopy Suite (RMS), located in the Radiochemical Processing Laboratory (RPL) at PNNL. ToF-SIMS analysis of unirradiated samples was performed in the Biological Science Facility. ToF-SIMS analysis of irradiated samples was performed in the W. R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored for the Department of Energy located at PNNL . PNNL is operated by Battelle under the contract DE-AC05-76RL01830. The authors are grateful for the support from the PNNL Nuclear Processing and Sciences Initiative (NPSI) - Laboratory Directed Research and Development (LDRD) fund. The authors would like to thank the Tritium Modernization Program of the Department of Energy's National Nuclear Security Administration, (DOE/NNSA) for additional support. The authors are indebted to Dr. David Senor for insightful discussions of sample selections and Michael Perkins for graphic support. SEM-FIB and AFM analyses were performed in the Radiological Microscopy Suite (RMS), located in the Radiochemical Processing Laboratory (RPL) at PNNL. ToF-SIMS analysis of unirradiated samples was performed in the Biological Science Facility. ToF-SIMS analysis of irradiated samples was performed in the W. R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored for the Department of Energy located at PNNL. PNNL is operated by Battelle under the contract DE-AC05-76RL01830.
Keywords
- Cladding
- Depth profiling
- Lithium
- Multimodal imaging
- Tritium