Radiation phenomena in Fe18 Cr10 NiTi steel Swelling

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Radiation phenomena in Fe-18 Cr-10 Ni-Ti steel • Swelling – Sokolovsky D. • Irradiation

Radiation phenomena in Fe-18 Cr-10 Ni-Ti steel • Swelling – Sokolovsky D. • Irradiation creep – Makarov E. • Evolution of Microstructure – Markelov D. 3

Conditions of irradiation of the former and elements from various reactors from steel type

Conditions of irradiation of the former and elements from various reactors from steel type Fe-18 Cr-10 Ni-Ti DPA rate, dpa/year Operating or irradiation time, years Reactor Elements Тirr. , о. С VVER-1000 Former 285 -410 (450) water 3 -75 0, 06 -2, 5 30 ВВЭР ТОИ Former 285 -370 water 5 -160 До 2, 7 60 The VVER-1000 elements of 265 -320 VVER-440 FA water 0 -22 0, 1 -3, 5 3 -6 BOR-60 Samples for 330 -350 testing sodium 5 -45, 100 5 -17 1 -7 BOR-60 Reflector assemblies 330 -380 sodium 10 -150 0, 1 -3, 5 22 -41 BOR-60 Creep samples 330 -420 sodium 0 -96 7 -18 3 -6 Environment 4

General view of engineering tensile diagrams of irradiated and non-irradiated austenitic steel Irradiated 20

General view of engineering tensile diagrams of irradiated and non-irradiated austenitic steel Irradiated 20 о. С 80 о. С 290 о. С unirradiated 5

Dose dependence of the yield strength of Fe-18 Cr-10 Ni-Ti steel irradiated in different

Dose dependence of the yield strength of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors 6

Dose dependence of the strength of Fe-18 Cr-10 Ni-Ti steel irradiated in VVER-1000 and

Dose dependence of the strength of Fe-18 Cr-10 Ni-Ti steel irradiated in VVER-1000 and VVER-440 reactors (265 -320 o. C) Тобл. ~ Тисп. = 300 о. С 0. 2 = 0. 2 + 0. 2 (исх. ) = А(1 -ехр(-Кt/Do))1/2 + 0. 2 (исх. ) А=500 МПа, Dо=4, 7 сна 7

Comparison of calculated and experimental hardening of Fe-18 Cr-10 Ni-Ti steel samples irradiated in

Comparison of calculated and experimental hardening of Fe-18 Cr-10 Ni-Ti steel samples irradiated in VVER-1000 reactor 0. 2 = Gb. М(N*D)1/2 8

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors Ttest ~ Tirr ~ 300 о. С 9

Yield strength versus damage dose 316 CW samples irradiated in rows 8 and 2

Yield strength versus damage dose 316 CW samples irradiated in rows 8 and 2 in EBR-II T. R. Allen, J. I. Cole, F. Garner et al. Journal of Nuclear Materials, 2006 – V. 348. P. 148 -164 EBR-II reactor: Material – identical; Temperature – identical; Dpa rate row #2 more then row #8 in 4 times Yield strength 316 CW samples irradiated in row #2 more then in row #8 10

The influence of the dpa rate at mechanical properties of annealing 316 SS irradiated

The influence of the dpa rate at mechanical properties of annealing 316 SS irradiated in the French fast neutrons reactors Yield Strength, MPa Phenix and Rapsodie reactors; Material – identical; Temperature – identical (400 -450 о. С); Dpa rate in Phenix more Phenix then Rapsodie in 3 Rapsodie times; Yield strength samples made from annealing 316 SS irradiated in 316 SS Phenix more then in Phenix Rapsodie reactor. Damage dose, dpa Dupouy, J. -M. , Erler, J, Huillery, R. Post. Proceedings of the International Symposium “Radiation Effects in Breeder Reactor Structural Materials”, New York. : The Metallurgical Society of AIME, 1977. P. 83 -93 11

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors Ttest ~ Tirr ~ 300 о. С 12

Dose dependence of hardening (increase of yield strength) of samples Выводы по данному этапу

Dose dependence of hardening (increase of yield strength) of samples Выводы по данному этапу исследования of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors Ttest ~ Tirr ~ 300 о. С BOR-60, AISI 304 Reflector Assemblies flat samples BOR-60, 18 Cr-10 Ni SM-3, AISI 304 WWER-1000, 18 Cr-10 Ni WWER-440, 18 Cr-10 Ni 13

The materials and conditions of irradiation • Reflector Assembly Е-65 • Samples • •

The materials and conditions of irradiation • Reflector Assembly Е-65 • Samples • • The exposure time - 41 years Damage dose ~ 107 dpa Dpa rate – 2, 6 dpa/year Irradiation Temperature – 330 -350 о. С The exposure time in the core – 7 years Damage dose ~ 102 dpa Скорость набора дозы – 15 dpa/year Irradiation Temperature – 330 -350 о. С Mass fraction, %, по ГОСТ 5632 -72 Material Fe-18 Cr-10 Ni-Ti C Si Mn S ≤ 0, 12 ≤ 0, 8 ≤ 2, 0 ≤ 0, 02 P Cr Ni ≤ 0, 035 17, 0 -19, 0 -11, 0 Ti 5*С-0, 8 14

PHASE DIAGRAM OF STAINLESS STEELS Ni equivalent, % А А+М М А+δ А+М+δ δ

PHASE DIAGRAM OF STAINLESS STEELS Ni equivalent, % А А+М М А+δ А+М+δ δ Cr equivalent, % - Fe-18 Cr-10 Ni-Ti steel in initial condition - Ni enrichment and depletion due to swelling 15

ELECTRON MICROGRAPH TYPE 304 L STEEL NEUTRON IRRADIATED AT ~500°C α γ Transformation interface

ELECTRON MICROGRAPH TYPE 304 L STEEL NEUTRON IRRADIATED AT ~500°C α γ Transformation interface between γ and α phases in partially transformed 304 L steel γ-shells around the voids in irradiated (dark-field electron micrograph) (dark-field electron micrograph, 111 -γ reflection) 304 L steel Porter D. L. Ferrite formation in neutron-irradiated type 304 L stainless steel. Journal of Nuclear Materials v. 79 (1979) № 2 406 -411. 16

α-PHASE NEAR GRAIN BOUNDARIES a) b) α-phase (light particles) and carbides (dark particles) located

α-PHASE NEAR GRAIN BOUNDARIES a) b) α-phase (light particles) and carbides (dark particles) located near grain boundaries in Fe-18 Cr-10 Ni-Ti steel with swelling ~9% examined by TEM 17

The microstructure of sample Fe-18 Cr-10 ni-Ti steel irradiated in BOR-60 reactor (36 dpa,

The microstructure of sample Fe-18 Cr-10 ni-Ti steel irradiated in BOR-60 reactor (36 dpa, 420 о. С, σ= +220 МPа) +220 МPа 18

General view of the microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 41

General view of the microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 41 years, 2. 6 dpa/year 7 years, 15 dpa/year Общая дефектность стали на левом рисунке выше. The number of defects in the left drawing above. 19

Microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 2. 6 dpa/year, Swelling ~1,

Microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 2. 6 dpa/year, Swelling ~1, 9 % 15 15 dpa/year, Voids not detected Voids The average voids diameter - 19, 4 nm, concentration - 3, 4*1021 m-3 Frank loops The average diameter - 8 nm, concentration - 2, 4· 1022 m-3 The average diameter - 11 nm, concentration - 6, 8· 1022 m-3 20

Phase structure 2, 6 dpa/year 15 dpa/year Particle radiation-induced G-phase with a stoichiometric formula

Phase structure 2, 6 dpa/year 15 dpa/year Particle radiation-induced G-phase with a stoichiometric formula Me 6 Ni 16 Si 7 with the FCC lattice Red background – matrix; Black line – phase; phase enriched in Nickel, manganese and silicon. 21

Alfa-phase structure Flat elongated particles of radiation-induced phase α-Fe with a length of 30

Alfa-phase structure Flat elongated particles of radiation-induced phase α-Fe with a length of 30 to 500 nm (2. 6 dpa/year) 22

Alfa-phase structure Particle radiation-induced α-Fe phase on the grain boundaries in the sample with

Alfa-phase structure Particle radiation-induced α-Fe phase on the grain boundaries in the sample with 15 dpa/year 23

General parameters of microstructure Fe-18 Cr-10 Ni-Ti steel irradiated with different dpa rate at

General parameters of microstructure Fe-18 Cr-10 Ni-Ti steel irradiated with different dpa rate at 102 -107 dpa Voids № Dpa Reflector 107 Core 102 G-phase Frank loops Тirr. °С 330350 dср, ρ, nm 1021 m-3 f, % dср, nm ρ, 1021 m-3 dср, nm ρ, 1022 m-3 19, 4 3, 4 1, 9 11, 5 3, 4 8 2, 4 - - - 7, 7 7, 3 11 6, 8 Изменение параметров микроструктуры позволяет говорить о том, что микроструктура образца, облученного в АЗ, находится в инкубационном периоде распухания, когда наблюдается более высокая концентрация частиц G-фазы и петель, что приводит к пониженному вакансионному пересыщению и отсутствию пористости. The change in the parameters of the microstructure suggests that the microstructure of the sample irradiated in the core, is in the incubation period of swelling when there is a higher concentration of particles of G-phase and the dislocation loops that leads to reduced vacancy supersaturation and the absence of porosity. 24

Evolution of low temperature radiation hardening on microstructural parameters (320 -350 o. C) Radiation

Evolution of low temperature radiation hardening on microstructural parameters (320 -350 o. C) Radiation hardening - the increase of the yield strength: Δσi = Мαμb√Nidi M – Taylor factor; α – the coefficient of “strength” of the barrier; – shear modulus; b – burgers vector; Ni – the concentration of barriers; di – average diameter of loops, voids, particles of phases ΔσƩ = Δσдисл. + Δσфаз + Δσпор + Δσальфа-фазы ΔσƩ = [(Δσдисл. )2 + (Δσфаз)2 + (Δσпор)2 + (Δσальфа-фазы)2]0. 5 Облучение до повреждающей дозы 25 -27 сна: - при облучении в АЗ, когда нет пористости и частиц альфа-фазы – есть только первые два слагаемых - при облучении в экране, когда нет пористости и частиц альфа-фазы – есть 2 слагаемых и суммарное упрочнение ниже, чем для материала, облученного в АЗ/ Irradiation of the samples up to 25 -27 dpa: - the irradiation of samples in the core, when there is no porosity and particulate alpha-phase – only first two summands; - the irradiation of samples in the reflector, when no porosity and particles of alpha phase – there are 2 components and the total hardening is lower than for a material irradiated in the core. 25

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti

Dose dependence of hardening (increase of yield strength) of samples of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors Ttest ~ Tirr ~ 300 о. С 26

Dose dependence of hardening (increase of yield strength) of samples Выводы по данному этапу

Dose dependence of hardening (increase of yield strength) of samples Выводы по данному этапу исследования of Fe-18 Cr-10 Ni-Ti steel irradiated in different reactors Ttest ~ Tirr ~ 300 о. С BOR-60, AISI 304 Reflector Assemblies flat samples BOR-60, 18 Cr-10 Ni SM-3, AISI 304 WWER-1000, 18 Cr-10 Ni WWER-440, 18 Cr-10 Ni 27

General view of the microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 41

General view of the microstructure of the samples of Fe-18 Cr-10 Ni-Ti steel 41 years, 2. 6 dpa/year 7 years, 15 dpa/year Спасибо за внимание! Thank you for your attention! Общая дефектность стали на левом рисунке выше. The number of defects in the left drawing above. 28