Publication: Radiation-induced ferrite formation as a potential issue in PWR austenitic internals following plant life extension
Дата
2019
Авторы
Merezhko, D. A.
Merezhko, M. S.
Gussev, M. N.
Maksimkin, O. P.
Garner, F. А.
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© 2019 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg. All rights reserved.Irradiation at PWR-relevant temperatures leads to multiple material degradation modes, including second-phase formation. It is known that formation of irradiation-induced bcc-ferrite can occur within austenite grains due to the tendency of nickel to segregate near the grain boundaries or void surfaces. In addition to affecting mechanical properties, ferrite may also affect cracking and corrosion behavior in water coolant, especially if the ferrite forms on grain boundaries. This work presents new high-fluence data derived from the BN-350 fast reactor to examine the potential for ferrite formation on grain boundaries in PWRs. The very low (<300°C) inlet temperature of BN-350 allows examination at PWR-relevant temperatures directly. When combined with several recent data sets at lower PWR-relevant dpa rates from BOR-60, which has a slightly higher (320-330°C) inlet temperature, it appears that very large amounts of ferrite can form on grain boundaries at temperatures and dose rates characteristic of PWR internals, allowing the possibility that a new degradation mechanism may assert itself at beyond-life-extension conditions, moving from previously second-order importance to a first-order concern at higher exposure levels.
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Radiation-induced ferrite formation as a potential issue in PWR austenitic internals following plant life extension / Merezhko, D.A. [et al.] // 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019. - 2019. - P. 615-624