glass ? From Fission Products Nuclear Glass to New Glasses - PowerPoint PPT Presentation

How to synthetize a good glass ? From Fission Products Nuclear Glass to New Glasses Florence Bart Nuclear Energy Division – Marcoule Center JOINT ICTP – AIEA WORKSHOP 10-14 SEPTEMBER 2018 – TRIESTE

What is a « Good » Glass ? | PAGE 2

3 The answer is evolving with time At the early Radionuclide beginning release in (50 ’ ) function of Intrinsic time, in « A glass durability of specific that can be the glassy storage poured is a material conditions good glass » Origin

A good glass is defined thanks to an iterative process between material and process developpement Glass melt properties L OADING RATE TECHNOLOGICAL FEASIBILITY Chemical Solubility Redox reactivity (Mo, Cr, Ru, S, … ) Thermal conductivity Phase separation Glass waste crystallization Electrical form conductivity Chemical durability Viscosity Thermal Radiation stability stability Glass Long term behavior Glass properties

Glass Formulation | PAGE 5

Solubility limits Major critical chemical elements coming from nuclear waste to be vitrified Phase separation and Mo molybdates crystallization Chemical reactivity, particle Ru, Pd, Rh, Ag settling, electrical conductivity, viscosity Nd, La, Pr, Ce, P Apatite crystallization Fe, Ni, Cr Spinel crystallization Ru, Cs, Tc Volatility

Important properties Viscosity Micro-homogeneity Chromites Palladium -Tellure Ceriumoxide Melting process can be RuO2 impacted by noble metal Silicophosphate content in glass melt Ca-molybdate (Convection, Pouring rate, Capacity)

Important properties Redox properties Thermal conductivity Ru métal RuO 2 O 2 bubbles Input data - Glass frit composition Thermodynamic data - (Fe 2+ /Fe 3+ ) in glass frit on redox equilibria Process - Waste composition in the glass parameters - Nitrate concentration Fe 2+ /Fe 3+ - Ce 3+ /Ce 4+ - Cr 3+ /Cr 6+ - - Melter atmosphere Mn 2+ /Mn 3+ - Ni 2+ /Ni 3+ - - Temperature Ru 0 /Ru 4+ …… .. - Oxygen fugacity in the final glass Final redox ratio M m+ /M (m+n)+ of multivalent elements in the glass

Long term behaviour | PAGE 9

Assessing long term behavior of vitreous matrices Initial Glassy state Groundwater composition, Fluid circulation Interactions with surrounding materials : clay, iron, cement Thermal stability Self irradiation Chemical Transformation of surrounding durability materials : metallic corrosion (0-300 years : (cumulative products 90-70 ° C) dose : 1 dpa) (performance assessment : 1 Self-Radiation Ma) Aqueous Radiation alteration damage Phase separation (source term: (electronic and Crystallization radionuclide nuclear release from the interactions, 2 µm Pristine package ) He production) glass Hydrated glass Macroporous Crystalline phases alteration layer Glassy state structural modifications

Glass alteration description and validation To describe macroscopic properties … H 2 O … from atomic to mesoscopic scale Archeological and natural analogs for validation Obsidian and basaltic Glass Basaltic glass: 1.4 glasses Ma Fractured archeological Iron (volcanic eruption) glass (Embiez), 1800 y. in Sea water Palagonite Steel production: Blast furnace slags from iron ore reduction Pristine glass (400 y. in an iron (anoxic burial medium) and clayey environment)

IRRADIATION DAMAGE : EFFECT ON GLASS STRUCTURE AND LONG TIME BEHAVIOUR Doped glasses Irradiation facilities ( 244 Cm , 238 Pu, 239 Pu, … .) Leaching tests and measurements Damage / properties modelling (effect of dose and dose rate) MD simulation of displacement cascade: accumulation of ballistic disordering 0.4SON68 1.2SON68 3.25SON68 KrSON68 AuSON68 HeSON68 244 CmO 2 ITU 1.7 3.0 CmO 2 JAERI AuCJ1 AuCJ3 AuCJ7 OSIRIS SON68  Thermal phase → local melting → 0 network reorganization Hardness variation (%) (rapid thermal quenching) -10  Stabilization of a new structural state -20 when all the volume has been damaged one time (~ 4x10 18 a /g) -30  Stabilization of macroscopic properties -40 (density, hardness … ) 17 18 19 20 21 22 10 10 10 10 10 10 -3 ) Deposited nuclear energy dose (keV.cm

VITRIFICATION PROCESSES Glass /Metal Glass Glass - Ceramic Matrice | PAGE 13

The first steps : Gulliver and Piver Gulliver (1964 – 1967) First French Vitrification pilot : heating of a gel, produced by FP impregnation of a clay material, in a refractory pot  170 kg of nuclear glass (10 kg per block) Glass frit sludge Piver (1969 – 1980) Semi-industrial process : glass is melted by batch, in a metallic melter, heated by induction, and then poured  13 tons of nuclear glass (25 m 3 of HLW FP solution) | PAGE 14

Development of the nuclear glass industry UMo Glass 2010 CCIM in R7 D&D Glass Two steps processes, cold 2004 CCIM crucible melter Pilot 2001 1994 UOX Glass 1992 T7 Start-up 1986 R7 Start-up AVM Glass 1978 AVM Start-up Piver Glass 70 ’ s Two-step Vitrification Process 60 ’ s Two steps Hot-wall Metallic Induction Melter (PIVER) 50 ’ s processes, Choice of Borosilicate Glass induction heated metallic melters PAGE 15

Calcination – Vitrification continuous two-steps process Surrogates Glass frit Additives Calciner Off-gas treatment Cold Crucible Hot Metallic Inductive Melter Melter Glass canister | PAGE 8

From glasses … to glass-ceramics Glass-ceramic Homogeneous Borosilicate Glasses Legacy waste : Molybdenum-rich fission product solutions (UNGG fuels)  Highly corrosive ILW glass, low solubilty of Mo into BSG  Designing a glass-ceramicmelted material  Homogeneous melt (1250°C)  Crystallizationwith cooling  Loading factor up to 13 wt% | PAGE 17

From induction heated metallic melter … Since 1990 Thermal flux from metallic walls to molten glass Hot Metallic Crucible Bubblers, rotary stirrers 5 vitrification lines in operation at AREVA La Pouring glass into Hague Facility stainless steel canister PAGE 18

… to cold crucible technology Since 2010 Thermal flux from the molten glass to the cooled crucible Cold CrucibleWater cooled metallic structure (higher temperature, no corrosion on the melter) 1 CCIM line in operation at Pouring into Glass ORANO La Hague Facility canister PAGE 19

NEW WASTE, NEW VITRIFICATION PROCESSES : IN-CAN TECHNOLOGIES | PAGE 20

Marcoule : industrial nuclear site under dismantling | PAGE 21

New sources of HL – IL Waste HLW coming from D&D operations • Small quantities, sludges or solids • Compositions are not as precisely defined as for FPS  Immobilization of TRU and FP into a durable matrix High active deposits from fission products evaporators and tanks ILW waste coming from MOX fuel Marcoule reprocessingfacility production • Alpha-bearing waste • Organic matter + metals : gloves, power cables, metallic material or tools, dusters …  Volume reduction  Organics destruction  Immobilization of TRU into a MELOX glove box (http://www.irsn.fr) durable matrix | PAGE 22

In can Melter for D&D HLW Currently developed by CEA* for its own waste coming from D&D operations, including legacy waste management Material and process specifications :  Flexible and adjustable to waste with a composition poorly defined : mixed effluents such as zeolites, co-precipitation sludges, powders of fuel debris (FP and alpha components)  Final waste package must be suitable with existing routes and/or on-site storage facilities  Compact size of the process, compliant with existing hot cells under dismantling  “ Dismantling tool ” that shall be itself dismantled after use (for re-use)  Low quantities of secondary waste  Minimum investment and operation cost *PIA project, national financial support, in collaboration with ANDRA, AREVA and ECM technologies | PAGE 23

In Can Melter : Main Features Process development criteria :  One step IN CAN vitrification (no calciner)  Container is used as a crucible renewed for each batch (no pouring)  Resistance heating, thermal homogeneization (no stirrer)  Design for liquid or solid feeding in a melting pot  Operating temperature < 1100 ° C *PIA project, national financial support, in collaboration with ANDRA, AREVA and ECM technologies | PAGE 24

In can Melter Glass Formulation criteria :  Minimization of FP volatilization (Cs)  Adjustable to accomodate composition uncertainties and variabilities  High content for P, Zr, Mo (a few wt%),  Low viscosity melts to ensure Microstructure of a simulated borosilicate homogeneization thanks to glass enriched with P and Zr oxydes showing numerous crystallizations thermal convection | PAGE 25

Material Science Challenges  To develop flexible glass formulations :  At relatively low elaboration temperature to avoid Cs volatilization  Suitable for P, Zr and Mo, elements that have a low solubility in borosilicate glasses  Compliant with variations of the feeding stream, characteristic of old deposits remaining in facilities that have been shut down, currently under dismantling  To develop final package description :  Source terms are needed, since these packages are designed for deep disposal | PAGE 26

INCINERATIONAND VITRIFICATION PROCESS : IN CAN MELTER | PAGE 27