Abstract
The influence of helium co-injection at rates from 0 to 4 appm He/dpa on swelling in ferritic-martensitic alloys T91 and HT9 was explored. Irradiations with 5.0 MeV Fe++ ions and degraded He++ ions were performed at 445°C up to damage levels of 150 dpa and helium co-injection rates of 0, 0.02, 0.2 and 4 appm He/dpa in T91, and at 460°C to a damage level of 188 dpa and helium co-injection rates of 0, 0.06 and 4 appm He/dpa in HT9. Helium was observed to enhance cavity nucleation at low damage levels, resulting in the maximum swelling at the highest helium co-injection rate. As the damage level was increased, the helium content at which swelling was maximized shifted to lower helium concentrations, ultimately resulting in the highest swelling occurring with zero helium by 150 dpa. This behavior was due to the helium-stabilized bubble microstructure that increased the cavity sink strength and reduced both cavity growth rate and swelling relative to the helium-free condition.
| Original language | English |
|---|---|
| Article number | 152912 |
| Journal | Journal of Nuclear Materials |
| Volume | 550 |
| DOIs | |
| State | Published - Jul 2021 |
| Externally published | Yes |
Funding
Support for D. Woodley partially provided by a DOE NEUP Graduate Fellowship. Support for S. Taller partially from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under contract DE-NE0000639. The authors gratefully acknowledge O. Toader, F. Naab, T. Kubley and E. Uberseder at the Michigan Ion Beam Laboratory for their assistance with ion irradiations, the financial support of TerraPower, Inc. through research roundtable agreement DRDA 11-PAF05786, the University of Michigan College of Engineering, NSF Grants #DMR-0723032 for support of the JEOL 2100F Probe-Corrected AEM, #DMR-9871177 for support of the JEOL 2010F AEM and #DMR-0320740 for support of the Thermo Fisher Nova 200 Nanolab SEM/FIB, and technical support from the Michigan Center for Materials Characterization staff.