Impact of hydrogen pick up and applied stress on c component loops: radiation induced growth of recrystallized zirconium alloys

Transcription

1 Impact of hydrogen pick up and applied stress on c component loops: Toward a better understanding of the radiation induced growth of recrystallized zirconium alloys L. Tournadre 1, F. Onimus 1, J.L. Béchade 1, D. Gilbon 1, J.M. Cloué 2, J.P. Mardon 2, X. Feaugas th International Symposium on Zirconium in the Nuclear Industry February 3-7, 2013, Hyderabad, India

2 INDUSTRIAL BACKGROUND & OBJECTIVES In-reactor elongation of the PWR fuel assembly Fuel assembly Irradiation growth stra in Stress free growth phenomenon Recrystallized alloys Breakaway growth Time in reactor (fluence n/m 2 or dpa) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 2

3 INDUSTRIAL BACKGROUND & OBJECTIVES In-reactor elongation of the PWR fuel assembly growth stra in Stress free growth phenomenon Recrystallized alloys a-loops 10 nm Fuel assembly Irradiation Breakaway growth Time in reactor (fluence n/m 2 or dpa) 50 nm V I <a> L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 3

4 INDUSTRIAL BACKGROUND & OBJECTIVES In-reactor elongation of the PWR fuel assembly growth stra in Stress free growth phenomenon Recrystallized alloys a-loops 10 nm Fuel assembly Irradiation Breakaway growth Time in reactor (fluence n/m 2 or dpa) 50 nm c-component loops V V I g=0002 Thin foil thickness <a> L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 4

5 INDUSTRIAL BACKGROUND & OBJECTIVES AREVA background: Fuel assembly growth acceleration phenomenon slightly different than predicted Two origins can be considered : Coupling between creep and stress free growth Does a macroscopic stress influence the c-loop microstructure? Impact of the in-service hydrogen pick-up on the c-loops? McGrath et al. ASTM STP 1529 (2011) Does the hydrogen content influence the c-loop microstructure? To have a rapid answer to these two questions : Analytical study using charged particle irradiations - Improve the understanding of growth acceleration - Build a physically based model taking into account c-loops L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 5

6 CHARGED PARTICLE IRRADIATIONS Zr ion irradiations Proton irradiations At CSNSM Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse At MIBL Michigan Ion Beam Laboratory ARAMIS 2 MeV Tandem IRMA 190 kev ion implantor 1,7 MeV Tandetron 2D thermal camera Proton source and high voltage generator Irradiation room Samples Temperature: 300 C 350 C Zr ion energies: 600 kev (ARAMIS) / 300 kev (IRMA) Temperature: 350 C Protons energy: 2 MeV Aperture Irradiation time (1 day) Irradiation time (200 h) Superficial damage on 300 nm (~0,05 grain) Damage on 30 µm (~6 grains) 7 irradiations completed 6 irradiations completed L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 6

7 STUDIED MATERIALS Two recrystallized Zr alloys studied: Recrystallized Zircaloy-4 (RXA Zy-4) M5 TM Alloying (weight ppm) Sn Nb Fe Cr O RXA Zy-4 ~ M5 TM Intermediate product : thick tube m 100 µ C-axis 3 mm TEM bright field pictures with a g=0002 diffraction vector Observed areas, thickness of ~200 nm Thick Tube Cladding RXA Zy-4 C-loop observation easier by Transmission Electron Microscopy (TEM) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 7 50 µm

8 ZR ION IRRADIATION & EFFECT OF AN APPLIED STRESS CEA 10 AVRIL 2012 PAGE 8

9 ZR ION IRRADIATION CONTROL SAMPLES 600 kev Zr ions 300 C Zr ions (300 C / 350 C) PWR Zy-4 RXA Zy-4 Linear density L V (m 2 ) PWR M5 M5 TM PWR (RXA Zy 4) PWR (Low tin RXA Zy 4) PWR (M5 TM ) C-loops observed after Zr ion irradiations L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 9

10 CEA STRESS DEVICE FOR ZR ION IRRADIATION Original 4-point bending device developed at CEA Irradiated surface. Stress directly linked to the applied deformation - Irradiation up to 4.1 dpa without stress - Stress applied after 4.1 dpa irradiation (when c-loops are already created), up to 7 dpa - Rapid relaxation of the stress in the irradiated layer (due to irradiation creep) Rem : high applied stress (close to yield stress) not representative of in-reactor loading Effect of stress on c-loops? L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 10

11 STRESS APPLIED ON C-LOOPS ZR ION IRRADIATION Pre-irradiated Zy-4 (4.1 dpa) applied stress ( yield stress) during 2.9 dpa. Total dose : 7 dpa Stress applied perpendicular to the c-axis High c-loop densities L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 11

12 STRESS APPLIED ON C-LOOPS ZR ION IRRADIATION Pre-irradiated Zy-4 (4.1 dpa) applied stress ( yield stress) during 2.9 dpa. Total dose : 7 dpa Stress applied perpendicular to the c-axis High c-loop densities L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 12

13 STRESS APPLIED ON C-LOOPS ZR ION IRRADIATION Pre-irradiated Zy-4 (4.1 dpa) applied stress ( yield stress) during 2.9 dpa. Total dose : 7 dpa Stress applied perpendicular to the c-axis c axis High c-loop densities Applied stress closer to the c-axis C-loop density decreases C-loop density decreases if the stress is applied along the c-axis L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 13

14 EXPERIMENTAL RESULTS VS. SIPA MECHANISM C-loop densities vs. RXA Zy-4 after Zr ion irradiations : 1,2E+14 1E+14 8E+13 Linear density ( ) L v Counted loops : 5240 N d V Thickness measured by EELS Mean diameter (nm) 2 (max) 0 1/3 0 1/3 2/3 Stress deviatoric component along the c axis (fraction of ) 6E+13 3E+21 2,5E+21 Number of c loops per unit volume (m 3 ) 4E+13 2E+13 control sample 2E+21 1,5E+21 1E (max) 0 1/3 0 1/3 2/3 Stress deviatoriccomponent alongthe c axis (fraction of ) 5E /3 0 1/3 2/3 Stress deviatoric component along the c axis (fraction of ) Results in good agreement with the SIPA mechanism (Garner et al., 1979) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 14

15 STRESS INDUCED PREFERENTIAL ABSORPTION (SIPA) Absorption bias of point defects by loops ( ) is modified by the deviatoric stress : Influence on the Stress applied perpendicular to c-axis : (Garner et al., 1979) Absorption of SIA Net vacancy absorption L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 15

16 STRESS INDUCED PREFERENTIAL ABSORPTION (SIPA) Absorption bias of point defects by loops ( ) is modified by the deviatoric stress : Influence on the Stress applied perpendicular to c-axis : (Garner et al., 1979) Absorption of SIA Net vacancy absorption C-loop growth L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 16

17 STRESS INDUCED PREFERENTIAL ABSORPTION (SIPA) Absorption bias of point defects by loops ( ) is modified by the deviatoric stress : Influence on the Stress applied perpendicular to c-axis : (Garner et al., 1979) Absorption of SIA Net vacancy absorption C-loop growth L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 17

18 STRESS INDUCED PREFERENTIAL ABSORPTION (SIPA) Absorption bias of point defects by loops ( ) is modified by the deviatoric stress : Influence on the Stress applied perpendicular to c-axis : (Garner et al., 1979) Absorption of SIA Net vacancy absorption C-loop growth Stress applied along the c-axis : Absorption of SIA Net vacancy absorption C-loop shrinking L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 18

19 PROTON IRRADIATION & EFFECT OF HYDROGEN CONTENT CEA 10 AVRIL 2012 PAGE 19

20 PROTON IRRADIATIONS CONTROL SAMPLES 2 MeV p protons 350 C 2 MeV protons C C N d V PWR Zy-4 Counted loops : 6566 Lv RXA Zy-4 PWR M5 M5TM PWR (RXA ( Zy 4)) PWR (Low tin RXA Zy 4) PWR (M5TM) C-loops C loops observed after proton irradiations Effect of the Zr alloy chemical composition in agreement with neutron irradiation Study of the effect of H mainly conducted on the M5TM + avoid H desorption L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 20

21 IMPACT OF HYDROGEN IN THE MATRIX M5 TM : irradiated up to 4.9 dpa 2 MeV protons 350 C <c+a> dislocation 200 nm Control 200 nm 350 sample wppm No c-loop at 4.9 dpa Pre-hydrided at 350 ppm C-loops observed at 4.9 dpa Incubation dose higher than 4.9 dpa Incubation dose lower than 4.9 dpa Hydrogen reduces the incubation dose for c-loop nucleation L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 21

22 IMPACT OF HYDROGEN IN THE MATRIX At 19 dpa 350 C M5TM : effect of H in the matrix (far from precipitated hydrides) Control sample 80 ppm 19 dpa In pre-hydrided samples : Density slightly higher C-loop microstructures more homogeneous Also observed at 8.1 dpa and 12.5 dpa L. Tournadre, et al. 350 ppm 19 dpa 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 22

23 IMPACT OF HYDROGEN IN THE MATRIX M5 TM 19 dpa 350 C Thickness measured by Energy Electron Loss Spectroscopy density Mean value 5 grains 2215 loops Mean value 4 grains 3453 loops Linear Mean value 6 grains 2158 loops Mean value 5 grains 2285 loops 19 dpa Hydrogen content (wppm) Hydrogen atoms in solid solution enhances the nucleation / growth of c-loops L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 23

24 EFFECT OF HYDROGEN ON C-LOOPS Hydrogen atoms in solid solution (~100 wppm at 350 C) : Trapped on the stacking fault disk Reduce the c-loop basal stacking fault energy Trapped in the stress field of c-loop dislocation lines Reduce the elastic energy Total c-loop energy Domain and al. ab initio calculations + experimental results (Vizcaino, McMinn and al.) Girardin, PhD (2010), Oudriss et al. OCAS (2011) Emission of vacancy C-Loop growth B L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 24

25 EFFECT OF HYDROGEN ON C-LOOPS Hydrogen atoms in solid solution (~100 wppm at 350 C) : Trapped on the stacking fault disk Reduce the c-loop basal stacking fault energy Trapped in the stress field of c-loop dislocation lines Reduce the elastic energy Total c-loop energy Domain and al. ab initio calculations + experimental results (Vizcaino, McMinn and al.) Girardin, PhD (2010), Oudriss et al. OCAS (2011) Emission of vacancy C-Loop growth B L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 25

26 EFFECT OF HYDROGEN ON C-LOOPS Hydrogen atoms in solid solution (~100 wppm at 350 C) : Trapped on the stacking fault disk Reduce the c-loop basal stacking fault energy Trapped in the stress field of c-loop dislocation lines Reduce the elastic energy Total c-loop energy Domain and al. ab initio calculations + experimental results (Vizcaino, McMinn and al.) Girardin, PhD (2010), Oudriss et al. OCAS (2011) Emission of vacancy C-Loop growth B L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 26

27 EFFECT OF HYDROGEN ON C-LOOPS Hydrogen atoms in solid solution (~100 wppm at 350 C) : Trapped on the stacking fault disk Reduce the c-loop basal stacking fault energy Trapped in the stress field of c-loop dislocation lines Reduce the elastic energy Total c-loop energy Domain and al. ab initio calculations + experimental results (Vizcaino, McMinn and al.) Girardin, PhD (2010), Oudriss et al. OCAS (2011) Emission of vacancy C-Loop growth B L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 27

28 EFFECT OF HYDROGEN ON C-LOOPS Hydrogen atoms in solid solution (~100 wppm at 350 C) : Trapped on the stacking fault disk Reduce the c-loop basal stacking fault energy Trapped in the stress field of c-loop dislocation lines Reduce the elastic energy Total c-loop energy Domain and al. ab initio calculations + experimental results (Vizcaino, McMinn and al.) Girardin, PhD (2010), Oudriss et al. OCAS (2011) Emission of vacancy C-Loop growth B Hydrogen atoms trapped could enhance c-loops nucleation and growth L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 28

29 EXPERIMENTAL RESULTS : C-LOOP BUNDLES Formation of c-loop bundles: example of the 350 wppm M5TM At 19 dpa 350 C OR2 Locally high c-loop densities In some specific areas, c-loops gathered as bundles Former δ-hydrides δ hydrides now partially or completely dissolved (<c+a> dislocations) Also observed at lower irradiation doses and for lower hydrogen content (80 ppm) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 29

30 EXPERIMENTAL RESULTS : C-LOOP BUNDLES Formation of c-loop bundles: example of the 350 wppm M5TM At 19 dpa 350 C OR2 200 nm Locally high c-loop densities In some specific areas, c-loops gathered as bundles Former δ-hydrides δ hydrides now partially or completely dissolved (<c+a> dislocations) Also observed at lower irradiation doses and for lower hydrogen content (80 ppm) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 30

31 EXPERIMENTAL RESULTS : C-LOOP BUNDLES Formation of c-loop bundles: example of the 350 wppm M5TM At 19 dpa 350 C OR2 200 nm Locally high c-loop densities In some specific areas, c-loops gathered as bundles Former δ-hydrides δ hydrides now partially or completely dissolved (<c+a> dislocations) Also observed at lower irradiation doses and for lower hydrogen content (80 ppm) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 31

32 EFFECT OF HYDROGEN ON C-LOOPS Dissolved hydrides : Hydride dissolution: a source of hydrogen atoms enhance loop growth <c+a> remaining accommodation dislocations after dissolution: c-loops nucleation site? g=0002 Helical climb of <c+a> dislocation and/or dissociation in the basal plane of the <c+a> dislocation + climb of the partial dislocation b <c+a> B b 1 b 2 B b <c+a> π 50 nm - Hydride : source of hydrogen - <c+a> dislocations as a nucleation site for c-loops L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 32 π

33 CONCLUSION C-loops observed after Zr ion and proton irradiations Macroscopic stress : SIPA mechanism observed on RXA Zy-4, (for high stress not representative of PWR conditions) Hydrogen impact : Clearly observed on M5 TM with 350 ppm hydrogen Impact of H in solid solution (effect on the basal stacking fault energy) Impact of dissolved hydrides (c-loop bundles) (source of hydrogen, c+a dislocation as nucleation site for c-loops) L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 33

34 Thank you for your attention! L. Tournadre, et al. 17th International Symposium on Zirconium in the Nuclear Industry, February 3-7, 2013, Hyderabad, India 34