Are mesoporous silicas resistant to radiation damage?

Transcription

1 INSTITUT DE CHIMIE SEPARATIVE DE MARCOULE Are mesoporous silicas resistant to radiation damage? X. Deschanels, Y. Lou, S. Dourdain, C. Rey CEA, ICSM UMR 5257 CEA-CNRS-UM-ENSCM, Bagnols-sur-Cèze Cedex, France XXth Colloque Ganil October 2O17

2 Marcoule Institute for Separation Chemistry Joint Research Unit (UMR 5257) between CEA, CNRS, Montpellier University, and Chemistry School of Montpellier ENSCM. Research teams Support teams Hybrid Materials for Separation (LHYS, D. Meyer) Ions at Interfaces (LIIA, O. Diat) Ion separation using supra-molecular selfassembled colloids(ltsm, S. Pellet-Rostaing) GEN IV Nuclear reactors Study of matter in Environmental Conditions (LM2E, R. Podor) Mesoscopic Modelling and Theoretical Chemistry (LMCT, J.-F. Dufrêche) Sonochemistry in Complex Fluids (LSFC, S. Nikitenko) Nanomaterials for Energy and Recycling processes (LNER, X. Deschanels) Fuel fabrication Back end of fuel cycle Evolving interfaces in materials (LIME, N. Dacheux) X-ray reflectivity and Grazing incidence X-ray diffraction And DTA/TGA, N2, Kr and H2O adsorption-desorption, GC-MS, X-ray fluorescence. Understand Separation Optimize separation Green chemistry Anticipate life-cycle Methods and theory 1

3 Context and goals Mesoporous materials : - 2 nm < d pore < 50 nm (IUPAC definition) - Mesoporous materials enable access to (strong) curvatures in solid state chemistry - Mesoporous materials are error tolerant and tend to reorganise spontaneously Radiation tolerance? - Interfaces act as sinks for irradiation induced point defects (Frenkel pairs) - Size of displacement cascade ~ Size of the mesoporosity Mesoporous silica - Size and organization of the mesoporosity can be easily tuned (elaboration by sol-gel process) - Many studies on radiation behavior of dense silica and several on Vycor glass (Klaumunzer) Mesoporous SiO 2 layer deposited on Si wafer P. Makowski, X. Deschanels, A. Grandjean, D. Meyer, G. Toquer, F. Goettmann, New. J. Chem. 36 (2012) 531 S. Klaumünzer, Nucl. Instr. Meth. Phys. Res. B 225 (2004) , 191 (2002) , (2000)

4 Elaboration of the film Sol-Gel route Hydrolysis : Si-(OR 4 ) + x H 2 O (OH) x -Si-(OR) 4-x + x R-OH Condensation : (OR 3 )-Si-OH + HO-Si-(OR 3 ) (OR 3 )-Si-O-Si-(OR 3 ) + H 2 0 CTAB : CHBrN Spherical 3D Ø~ 2-3 nm Templating agent : P123: COH Cylindrical 2D Ø~ 4 nm F127: COH Spherical 3D Ø~ 4 nm Dip coating Obtained morphologies Dourdain, S.; Bardeau, J.-F.; Colas, M.; Smarsly, B.; Mehdi, A.; Ocko, B. M.; Gibaud, A., Appl. Phys. Lett. 2005, 86 (11),

5 Objectives and Methodology Electronic process (Xe 92 MeV) SiO 2 Mesoporous silica Thin layer of Si/SiO 2 (e~ nm) Mesoporous sol-gel silica Si wafer Ballistic process (Au 0.5 to 12 MeV) Analysis techniques: X-ray reflectivity, FTIR, SEM Objectives - Mesoporous structure evolution as well as silica network as a function of irradiation conditions - Influence of stopping power, dose, pore morphology - Understanding of damage mechanisms 4

6 Irradiation conditions Ion Sample de/dx Elec (kev/nm) de/dx Nucl (kev/nm) dpa at fluence cm -2 JANNuS Saclay Irrsud Au 0,5MeV 2D cyl 4nm 3D sph 2nm 3D sph 4nm Non porous 0,85 3,1 0,33 Au 3MeV 2D cyl 4nm 1,8 2,1 0,18 Au 7MeV 2D cyl 4nm 2,4 1,5 0,099 Au 12MeV 2D cyl 4nm 2,7 1,1 0,081 Xe 92MeV 2D cyl 4nm 11 ~0 ~0 Annealing at 400 C for sol-gel samples aims to stabilize the SiO 2 structure 5

7 Réflectivité (a.u.) Au 0.5 MeV- XRR measurements Effect of fluence Reflectivité (u.a.) 2D Cyl 4 nm - 1 dpa ~ 3x10 14 ion/cm 2 1,0 0,8 0,6 0,4 0,2 Global film density increase 0,0 0,2 0,3 0,4 0,5 0,6 2theta ( ) Substrate t = T = 2π Q z,bragg 2π Q z,kiessig 0 Au/cm 2 0,5E14 Au/cm 2 1E14 Au/cm 2 1,5E14 Au/cm 2 3E14 Au/cm 2 4E14 Au/cm 2 7E14 Au/cm 2 Total film thickness decrease 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 2theta ( ) Amorphisation, compaction and deformation of pores (XRR measurments) Confirmation by SEM observations Porosity layer decrease and loss of organised structure , Au/cm 2 Au/cm Au/cm 2 «Structure evolution of mesoporous silica under heavy ion irradiations of intermediate energies», Y. Lou, S. Dourdain, C. Rey, Y. Serruys, D. Siméone, N. Mollard, X. Deschanels Microporous mesoporous materials 251 (2017) 6

8 Reflectivity (a.u.) Reflectivity(u.a.) Reflectivity(u.a.) Reflectivity(u.a.) Reflectivity(u.a.) Reflectivity(u.a.) Au 0.5 MeV- XRR measurements Structure effects Global density (g/cm 3 ) 1,0 0,8 0,6 0,4 0,2 0,0 0,2 0,3 0,4 0,5 0,6 2theta ( ) 2D 4nm 3D 2nm 3D 4nm 2D cyl 4nm 0 Au/cm 2 0,5E14 Au/cm 2 1E14 Au/cm 2 1,5E14 Au/cm 2 3E14 Au/cm 2 4E14 Au/cm 2 7E14 Au/cm 2 2,4 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 2theta ( ) 3D 4nm 1,0 2,0 0,8 0,6 0,4 0,2 0,0 0,2 0,3 0,4 0,5 2theta 1,6 2D 4nm 3D 4nm 3D 2nm 3D sph 4nm 0 Au0,5MeV/cm 2 1E14 Au0,5MeV/cm 2 1, theta 3D 2nm 5E14 Au0,5MeV/cm 2 2E15 Au0,5MeV/cm Fluence (x10 14 Au/cm 2 ) 1,0 0,8 3D sph 2nm 0,6 0,4 0,2 0,2 0,3 0,4 0,5 2theta (? 0 Au0,5MeV/cm 2 1E14 Au0,5MeV/cm 2 5E14 Au0,5MeV/cm 2 Damage effect on the material: 2D 4nm > 3D 2nm > 3D 4 nm Cylindric > spheric Small pores > large pores 2E15 Au0,5MeV/cm theta (? 7

9 Reflectivity(u.a.) Au irr. - XRR measurements Stopping power 2D cyl 4nm E14 ion/cm theta 0 Au 0,5MeV Au 3MeV Au 7MeV Au 12MeV Au 0, MeV Ion energy ballistic effect & electronic effect Damage effect Au 12MeV > Au 0.5 MeV > Au 7 MeV > Au 3 MeV Damage less important when electronic and ballistic effects are mixed 8

10 Thickness decrease (%) Au Irr. XRR measurments Stopping power "Cross-section diameter" (nm) 60 2D cyl 4nm 0,6 ρ ρ 0 = ρ ρ 0 sat (1 exp( σф)) Au 0,5MeV Au 3MeV Au 7MeV Au 12MeV Marples fit Au 0,5MeV Marples fit Au 3MeV Marples fit Au 7MeV Marples fit Au 12MeV 0,5 0, Fluence (x10 14 Au/cm 2 ) 0,3 0, Au energy (MeV) Quantitative confirmation U shape form for the plot of Cross section versus Energy - Au 12MeV > Au 0.5 MeV > Au 7 MeV > Au 3 MeV - Antagonism effect between electronic and ballistic stopping power Marples, J. A. C., Dose rate effects in radiation damage to vitrified radioactive waste. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 1988, 32 (1),

11 Réflectivité (a.u.) Réflectivité(a.u.) Electronic effects 2D Ø~4nm 2D F~4nm, 129 Xe, 92MeV, 11 kev/nm ,1 1,0 0,8 0,6 de/dx> track formation in dense SiO 2 100nm virgin 0,01 0,4 1E-3 1E-4 1E-5 1E-6 0,2 0,38 0,40 0,42 0,44 0,46 0,48 0,50 2theta ( ) SiO 2 Si 1E-7 1E-8 1E-9 1E E12 Xe/cm2 1E13 Xe/cm2 3E13 Xe/cm2 6E13 Xe/cm nm Irradiated 1x10 13 cm -2 2theta ( ) Collapse of the mesoporous structure for high fluence Observation of track by SEM SiO 2 Si Dourdain, S.; Deschanels, X.; Toquer, G.; Grygiel, C.; Monnet, I.; Pellet-Rostaing, S.; Grandjean, A., Radiation damage of mesoporous silica thin films monitored by X-ray reflectivity and scanning electron microscopy. JNM 2012, 427 (1 3),

12 Ballistic effects - Modelling Modelling Structure similar to thin layer 2D cyl-hex 4 nm Box creation: MonteCarlo Irradiation simulation : Molecular dynamics (Ballistic effects only) Mesostructure evolution (up to 1,2 dpa) Mesopore collapse and deformation of the mesoporous structure Box shrinkage 12

13 Number of surface atoms Ballistic effects - Modelling Surface atoms (Voronoï) Number of surface atoms ,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 Dose (dpa) At first, up to 0.4 dpa, increase of the nb. of surface atoms, ie rugosity and pore formation in the wall of the silica network For higher damage, decrese in the nb. of surface atoms, ie collapse of the mesoporous structure 13

14 Compaction (%) Conclusions Ballistic, Au irr Au 0,5MeV sur couche mince Au 12MeV sur couche mince 58Ni 638MeV sur SBA-15 20Ne 278MeV sur SBA-15 Xe 92MeV sur couche mince de/dx>5kev/nm, track de/dx<1kev/nm 0,01 0, Electronic dose (10 21 kev/cm 3 ) - Compaction is dependant on the stopping power of the ions - Ballistic effects lead to higher damage than electronic ones - The size of the mesopore is a crucial parameter In some extent mesoporous materials present tolerance to radiation damage 1314

15 Separation conditioning process Nuclear waste management Adsorption of the selected radionuclide Encapsulation of the radionuclide by subsequent collapse of the structure (Thermal stress, chemical stress ) SiO 2 Functionalized Selective separation Conditioning Field of application Outflows coming from dismantling sites Pore collapse (Thermo-mechanical or radiation stress) 15

16 Institut de Chimie Séparative de Marcoule UMR 5257 CEA CNRS UM ENSCM Site de Marcoule Bâtiment 426 BP F Bagnols-sur-Cèze Cedex T. +33 (0) F. +33 (0) Thank you for your attention Thanks to C. Grygiel, I. Monnet, F. Durantel at GANIL facility Thanks to Y.Serruys and all the staff of JANNUS-Saclay Thanks to B.Siboulet and J-M.Delaye for modelling study Thanks to EMIR network for irradiation and to the GDR Needs «Déchets» for funding