Abstract
Elemental composition and morphology of a previously unidentified radiation-induced ferrite phase were investigated in a 300-series steel irradiated by neutrons in-service up to 57.6 dpa. Specimens of 18Cr-10Ni-Ti stainless steel (AISI 321 analog) were cut from a hexagonal wrapper of a fuel assembly irradiated in the BN-350 sodium-cooled fast reactor. An Fe-rich bcc-phase was observed primarily on grain boundaries. In this phase, the concentration of Cr is ∼8–12% (compared to ∼19% in the matrix), the concentration of Ni is ∼1.5–3% (∼9% in the bulk material), and the concentration of Mn is ∼0.23% (1.3% in the matrix). This Fe-rich phase is distinctly different from the retained-ferrite phase, commonly found in commercial austenitic steels. The extensive appearance of this Fe-rich ferrite on grain boundaries suggests that enhanced surface–intergranular corrosion may occur in water-cooled power reactors, arising from the low Ni, Mn, and Cr concentrations in this phase.
Original language | English |
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Article number | 114690 |
Journal | Scripta Materialia |
Volume | 215 |
DOIs | |
State | Published - Jul 1 2022 |
Funding
The research was funded by the Ministry of Education and Science of the Republic of Kazakhstan (Grant no. AP08052488). This research was supported in part by the US Department of Energy , Office of Nuclear Energy, Light Water Reactor Sustainability Program under contract DE-AC05–00OR22725 with UT-Battelle LLC via Oak Ridge National Laboratory. The authors wish to express their gratitude and appreciation to the leadership of recently deceased Prof. Oleg P. Maksimkin (Institute of Nuclear Physics, Almaty, Kazakhstan) in providing resources to conduct this experiment.
Funders | Funder number |
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Office of Nuclear Energy, Light Water Reactor Sustainability Program | DE-AC05–00OR22725 |
U.S. Department of Energy | |
Oak Ridge National Laboratory | |
Ministry of Education and Science of the Republic of Kazakhstan | AP08052488 |
Keywords
- Austenitic steels
- Corrosion
- Ferrite phases
- Grain boundaries
- Irradiation-induced phase transformation