NSUF 18-1403: Nanostructuring to enhance irradiation tolerance of ferritic/martensitic Grade 91 steels
F/M steels such as Grade 91 are leading fuel cladding and structural materials for advanced fast reactors. Development of fast reactors require steels with enhanced irradiation tolerance and higher strength. Nanostructured steels possess dramatically higher strength than their conventional coarse-grained (CG, grain diameter >1 µm) counterparts, owing to significant grain boundary (GB) strengthening, and have significantly enhanced irradiation tolerance due to significant volume fraction of GBs that serve as sinks or recombination centers for radiation-induced defects. However, there has been very limited studies on irradiation of nanostructured steels, and their performance under irradiation at relevant reactor operating temperatures remains unclear. In addition, irradiation effects such as irradiation-induced segregation have not been established as a function of grain size. This proposed work will systematically study the irradiation performance of Grade 91 steel with different grain size ranges, assess their potential applications in LWRs and advanced fast reactors as structural materials or fuel cladding, and establish/enhance our fundamental understanding of irradiation effects in these materials. The establishment of irradiation performance of nanostructured F/M steels with appealing properties will impact the life extension of current reactors and the development of advanced reactors. Hence, the proposed research is highly relevant to DOE-NE’s Light Water Reactor Sustainability program and Advanced Fast Reactor program. The project will use ion irradiation to study irradiation behavior. Conventionally processed CG, ECAP processed UFG, and HPT processed NC Grade 91 steel samples will be subjected to ion irradiation at different temperatures to different doses. The post-irradiation examination (PIE) will include mechanical testing and microstructural examination. Mechanical properties and microstructures of the steel samples after irradiation will be compared to those before irradiation so that the irradiation effects on microstructural evolution and mechanical properties can be determined, with focus on irradiation-induced hardening, solute segregation, and phase transformation. Irradiation effects in CG, UFG and NC steel will be compared, and irradiation tolerance will be studied as a function of grain size.
Additional Info
| Field | Value |
|---|---|
| Abstract | F/M steels such as Grade 91 are leading fuel cladding and structural materials for advanced fast reactors. Development of fast reactors require steels with enhanced irradiation tolerance and higher strength. Nanostructured steels possess dramatically higher strength than their conventional coarse-grained (CG, grain diameter >1 µm) counterparts, owing to significant grain boundary (GB) strengthening, and have significantly enhanced irradiation tolerance due to significant volume fraction of GBs that serve as sinks or recombination centers for radiation-induced defects. However, there has been very limited studies on irradiation of nanostructured steels, and their performance under irradiation at relevant reactor operating temperatures remains unclear. In addition, irradiation effects such as irradiation-induced segregation have not been established as a function of grain size. This proposed work will systematically study the irradiation performance of Grade 91 steel with different grain size ranges, assess their potential applications in LWRs and advanced fast reactors as structural materials or fuel cladding, and establish/enhance our fundamental understanding of irradiation effects in these materials. The establishment of irradiation performance of nanostructured F/M steels with appealing properties will impact the life extension of current reactors and the development of advanced reactors. Hence, the proposed research is highly relevant to DOE-NE’s Light Water Reactor Sustainability program and Advanced Fast Reactor program. The project will use ion irradiation to study irradiation behavior. Conventionally processed CG, ECAP processed UFG, and HPT processed NC Grade 91 steel samples will be subjected to ion irradiation at different temperatures to different doses. The post-irradiation examination (PIE) will include mechanical testing and microstructural examination. Mechanical properties and microstructures of the steel samples after irradiation will be compared to those before irradiation so that the irradiation effects on microstructural evolution and mechanical properties can be determined, with focus on irradiation-induced hardening, solute segregation, and phase transformation. Irradiation effects in CG, UFG and NC steel will be compared, and irradiation tolerance will be studied as a function of grain size. |
| Award Announced Date | 2018-05-17T10:59:25.017 |
| Awarded Institution | Center for Advanced Energy Studies |
| Facility | Microscopy and Characterization Suite |
| Facility Tech Lead | Kumar Sridharan, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Haiming Wen |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1403 |