NSUF 25-5230: Determination of Swelling Across Temperatures in Vanadium Alloys Without Transmutation
Vanadium alloys were developed as candidate alloys for cladding materials of Liquid Metal Fast Breeder Reactors in the 1970s because of their favorable chemical compatibility with fuel. Vanadium alloys are being reconsidered as part of a multi-layer cladding where an external layer prevents the interaction with liquid sodium. Because of its proximity to the fuel, the temperature gradient within this cladding layer is expected to be significant, requiring modeling to determine how the dimensions of the fuel-clad system will evolve. The objective of this study is to determine the temperature dependence of swelling in vanadium and its alloys as a function of impurity content. We hypothesize that impurity control during processing of V-alloys will result in less or equal swelling to a traditional heat, demonstrating the necessity for impurity control. However, irradiation data on swelling for vanadium alloys in fast neutron spectrums is sparse. Limiting the ability to generate this performance data is the high thermal cross section for transmutation of V into Cr, approximately 22% of V into Cr by 30 DPA, making irradiation in the nation’s test reactors (ATR or HFIR) or commercial fleet non-representative of the fast neutron environment. Thus, ion bombardment with simultaneous helium co-injection emerges as the closest facsimile to the fast reactor environment. Therefore, we propose to determine the temperature dependence of swelling in vanadium and its alloys using dual ion irradiation in a temperature range and helium generation rate relevant to fast reactor applications. The proposing team seeks use, through the Nuclear Science User Facilities, of the Michigan Ion Beam Laboratory (MIBL) for dual ion irradiation of two variants of a nominally V-4Cr-4Ti alloy (V44) and one high purity vanadium control specimen, and of the Low Activation Materials Development and Analysis (LAMDA) laboratory for TEM lamella preparation and characterization of dislocation loops, precipitates, and cavities. Specimens will be characterized using on-zone axis STEM imaging for dislocation loops and cavities, with STEM-EDS and diffraction pattern analysis for precipitate composition and morphology. ORNL will provide a specimen of the legacy V44, heat 832665, which has a relatively high impurity content and a rich history as the US reference V44 heat. There are 3 alloys to be irradiated in seven dual ion irradiation experiments, and thus, in total, the proposed experiments will require an estimation of about 39 hours for beam time, 84 hours for lamella preparation and 36 hours for post-irradiation examination with transmission electron microscopy. If successful, the results will guide the development of vanadium alloys for fast reactor cladding applications and provide further evidence to support or refute the utility of ion irradiation as a technique to accelerate materials qualification for nuclear applications.
其他信息
| 域 | 价值 |
|---|---|
| Award Announced Date | 2025-08-06T10:06:56.687 |
| Awarded Institution | TerraPower |
| Facility Tech Lead | Kevin Field, Kory Linton |
| Irradiation Facility | Michigan Ion Beam Laboratory |
| PI | Matthew Weinstein |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |