Solute clustering in RPV steels under irradiation

Transcription

1 Solute clustering in RPV steels under irradiation P. Pareige, B. Radiguet, C. Pareige and A. Etienne C Groupe de Physique des Matériaux - UMR CNRS 6634 Université et INSA de Rouen Saint Etienne du Rouvray, France November 5-8, 2013 Vienna, IAEA Degradation of primary components of pressurised water cooled nuclear reactors: Current issues and future challenges

2 RPV steels under irradiation hardening Neutron irradiation T ~ 290 C ~ m -2.s -1 embritlement Origin : Point defects and their clusters, solutes/impurities and their clusters/precipitates, segregations (interfaces, boundaries, ),

3 Vessel steel in commercial reactor Atom Probe Tomography observations P Si Mn Ni Cu Fe Solute cluster P Si Mn Ni Cu nm 3 Segregation along dislocation nm 3 Objects Cluster (Matrix) Cluster (Dislocation) Dislocation P 0,11 ± 0,06 0,76 ± 0,14 0,53 ± 0,12 Si 8,84 ± 0,54 6,92 ± 0,41 6,10 ± 0,40 Mn 5,60 ± 0,44 8,10 ± 0,45 5,85 ± 0,40 Ni 10,76 ± 0,59 9,69 ± 0,48 7,20 ± 0,40 Cu 0,34 ± 0,11 0,40 ± 0,10 0,27 ± 0,08 Radius 1,4 1,5 - Density (10 22 m -3 ) 9.2 ± H. Huang, B. Radiguet, P. Pareige P. Todeschini C. Chainasse, F. Clémendot Join Laboratory EDF / CNRS EM2VM

4 Number Density (10 22 m -3 ) Radius (nm) Different vessel steels of commercial reactors Understanding basic mechanisms 30 2, Steel A (0,03 Cu) Steel B (0,044 Cu) Steel P1 A Steel BF1 Steel C (0,07 Cu) Steel D (0,07 Cu) Steell F2 C Linear (Steel A) Steel DF3 Linear (Steel B) Linear (Steel C) Linear (Steel D) y = 4,0x - 5,5 Vacancy cluster (MFVIC) 1, y = 3,9x - 4,9 y = 1,3x - 1,3 Cu y = 0,4x + 1,3 0 0, Neutron Neutron fluence fluence (10 ( n n m -2-2 ) ) Link microstucture and properties

5 Vessel steels in commercial and test reactors 5 16MND5 A533B 15Kh2MFA 15Kh2NMFAA Steel C P Si Mn Ni Cu Cr Mo V Steel EDF2 (MB) EDF3 (WM) FZD1a (JPB) AEK1 (BM) NRI1 (WM) EDF / 3.86 / EDF / 5.22 / 6.95 C FZD 1a November 5-8, 2013 Vienna, IAEA Bulk composition (at.%) T ( C) Flux (10 12 cm -2 s -1 ) Fluence (10 19 cm -2 ) AEK C ~ / 90.6 NRI ~ / 4.5 / 9.5

6 EDF samples 6 Irradiated conditions (EDF-2 and EDF-3 / t 1 - t 2 - t 3 ) - Solutes (Mn, Ni, Si, Cu, P) clusters located in the matrix or along dislocation lines (all EDF steels, all fluences) - Continuous segregation of the same elements along dislocation lines (all EDF steels, all fluences) EDF-2 / t 3 C One segregation on a loop? ~10 21 m -3 November 5-8, 2013 Vienna, IAEA

7 FZD-1 samples 7 Irradiated condition ( t 1 ) - Solute clusters P N = 24.3± m -3 R = 1.0±0.2 nm Ni: 6.9±0.3 Mn: 6.8±0.3 Si: 3.0±0.2 at.% P: 0.35±0.1 Cu: 0.07± nm 3 P Si Mn Ni Fe - P segregation along dislocation lines C Intergranular/lath segregation on boundary with twist component (?) November 5-8, 2013 Vienna, IAEA

8 AEK-1 samples 8 Irradiated conditions ( t 1, t 3 ) - Intergranular/lath segregation ( t 1 ) Low angle (?) High angle (?) θ ~ 2 C Strong influence of GB nature November 5-8, 2013 Vienna, IAEA

9 AEK-1 samples 9 - Continuous segregations (both fluences) Irradiated conditions ( t 1, t 3 ) Along dislocation lines 4,2 17 5,1 nm 3 Around dislocation loops 3,7 5,2 3,3 nm 3 - Solute clusters (both fluences) In the ferritic matrix Along dislocation lines Along dislocation loops (b) (c) At carbides/ferrite interfaces C Si P Mn Ni Cu Cr C V Mo Fe November 5-8, 2013 Vienna, IAEA

10 10 Grain / lath boundaries Solute clusters - Enrichment in C, Si, P, Cr, Mn, Ni, Mo often observed - Evidence of the influence of boundary nature on segregation - No clear evidence of irradiation effects C - No clear trend with fluence - Flux effect - Increase with fluence - T effect November 5-8, 2013 Vienna, IAEA

11 Experiment on model alloy: solute behavior? Temperature ( C) dpa/s 11 Fe-1%Mn 0,0007 0,0006 0,0005 0,0004 0,0003 0,0002 Fe MeV T = 400 C m -2.s -1 Needle thickness at.% Mn 0, Homogeneous damage Depth (nm) Both alloys prepared by levitation casting Dose (0.93±0.03) at.% Mn Fe-Mn 0.5 dpa Un-irradiated samples Homogenization treatment: 1000 C 840 C Air quenched Random solid solution at nm-scale Homogeneous at µm-scale (EPMA analysis)

12 Temperature ( C) FeMn alloy irradiated at 0.5 dpa Cluster composition Mn Formation of Mn rich clusters 12 Mn 30.8 ± 2.7 Fe 69.2 ± 2.7 (at.%) Radius (nm) Density (m -3 ) Fe 1.5 ± 0.2 (4.8 ± 1.4) ( Fe, Mn) nm 3 Bulk composition at.% Mn Mn cluster composition Clusters have the composition predicted by phase 400 C in a super saturated FeMn alloy

13 FeMn alloy irradiated at 0.5 dpa Planar defect = point defect sink 13 Local enrichment in Mn V / I flux Mn flux nm 3 V I Mécanisme interstitiel On point defect sink: C Mn > Mn solubility limit Heterogeneous nucleation nm 3 Radiation induced precipitation of Mn rich phase

14 Intra-granular segregation and precipitation in neutron irradiated 14 Fe-Cr- Si,Ni impurities alloys Fe-Cr alloys with different Cr content: Fe at.% Cr Fe at.%cr Bonny et al. Calphad Fe at.%cr Dose : 0.6 dpa Fe at%cr Neutron flux: n/(cm 2 s) Temperature: 300ºC BR2 reactor (SCK CEN) a a + a' MIRE-Cr irradiation program As measured with Atom-Probe Tomography (APT) in at.% Fe Bal. Fe Bal. Fe Bal. Fe Bal. Cr 2.21 ± 0.01 Cr 4.61 ± 0.02 Cr 9.16 ± 0.04 Cr 11.2 ± 0.04 Si ± Si ± Si ± Si 0.18 ± 0.01 Ni ± Ni ± Ni ± Ni 0.07 ± 0.01 P ± P 0.013± P ± P ± 0.002

15 Two independent families of clusters are revealed 15 NiSiPCr enriched cluster nm nm 3 Cr enriched clusters Fe-2.5%Cr Fe-5%Cr Fe-9%Cr Fe-12%Cr

16 Low angle tilt grain boundary Fe - 9%Cr Cr Si Fe - 12%Cr Twist grain boundary High angle grain boundaries Fe - 9%Cr nm nm 3 Segregation of Si

17 What about solute behavior in Duplex Stainless Steel? 17 T service (285 C 323 C) Aciers Duplex Austenite Ferrite : 10 à 30 % 40 m 1 mm Décomposition de la ferrite : α α + α α : iron rich ferritic phase α : chromium rich ferritic phase résilience KCV à 320 C ; résilience KCU à 20 C ; dureté Vickers HV30. Chemical C Cr Ni Si Mo Mn Fe composition % at. < 0,2 18 to 21 9 to 12 < 3 1,1 to 1,3 < 1,5 balance

18 Phase transformations Duplex stainless steels (DSS) 18 Ferrite decomposition during ageing Spinodal decomposition + Precipitation Cr rich α zones (threshold X Cr > 26%) Fe rich α zones V = nm 3 Mechanical properties G phase enriched in Ni, Si, Mn and Mo (threshold X Ni +X Si +X Mn >20%) Kinetic 2

19 Duplex stainless steels (DSS) 19 Spinodal decomposition Precipitation Slope = 0.16 Slope = 0.06 Slope = 0.15 Slope = 0.07 Synergy between spinodal decomposition and precipitation 3

20 Summary 20 Solutes and Impurities in BCC Iron : segregation and clustering or precipitation With Thermodynamic and/or point defects kinetics Structural evolution in RPV steels is at very beginning in comparison to other materials in other conditions what will be the evolution of clusters? C November 5-8, 2013 Vienna, IAEA 1 dpa = 10 highest RPV exposure Need of experiments/modelling

21 Equipment of Excellence GENESIS Groupe d'etude et de Nano-analyses des EffetS d'irradiations 21 Group for Studies and Nanoanalyses of Irradiation Effects Head of the project P. Pareige (GPM - Rouen) C. Pareige, A. Etienne, B. Radiguet Partners P. Yvon (CEA DEN/DMN - Saclay) S. Bouffard (CIMAP - Caen) 21

22 GENESIS: International Research Plateform Caen Rouen Saclay Glasses Ceramics Non active Fondamental / Applied researches, International Platforme, Education Metals Glasses Ceramics Activity up 200 MBq Metals Highly active Hot cells

23 Dual Beam SEM/FIB Atom Probes 23 EBSD 3D-FIB GIS/ micromanip. Laser and electric mode High pulse rate High mass resolution TEM «Station» Double tilt/rotation specimen holder + others specific holders STEM BF / ADF / HAADF EDS / EELS / EFTEM

24 1 c Time Experimental reactors MTR SFR Mechanical tests Structure 24 1 y Simulation by charged particles SANS TEM Dislocations and irradiation defects Microstructure 10 m 1 s TAP Atoms GENESIS Electrons 1 ps 40 nm 10 mm 1 mm Crystal Plasticity (CP) Homogenization Finite Elements (EF) Dislocations Dynamics (DD) Object or Event Monte Carlo (O or EkMC) Cluster Dynamics Molecular Dynamic (MD) Atomic Monte Carlo (AkMC) Electronic structure Ab initio (DFT-LDA) Space 1 nm 1 m March 3-7, 2013 San Antonio, Texas 1mm 24 1m

25 GENESIS: International Research Platform 25 Rouen (open March 2015) GENESIS GPM Rouen Plateform for Nanoanalyses of radioactive materials And Development of scientific collaboration Fundamental / Applied Contact researches, : P. Pareige (philippe.pareige@univ-rouen.fr) International Platform, Education