Glass as a Waste Form and Vitrification Technology Summary of an International Workshop (1996) / Chapter Skim
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Appendix E Abstracts of Invited Workshop and Poster Presentations
Appendix E Abstracts of Invited Workshop and Poster Presentations
Pages 53-162
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From page 54... ...
14 Mountain, Nevada, David Stahl, Framatome Cogema Fuels, Civilian Radioactive Waste Management System, M&O Contractor A Review of Status of Science of Vitrif ed Waste Form Development, George G. E 16 Wicks, Westinghouse Savannah River Technology Center [each Tests aids Chemical Durability, Robert H
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From page 55... ...
E.40 E.42 E.44 E.46 E.48 E.50 E.52 E.54 Natural Glasses as Analogs for Nuclear Waste Glasses, AbJesselam AbJelouas and E.56 Werner Lutze, University of New Mexico Alteration of Nuclear Waste Glasses Characterized by Radon Emanation Method, E.58 V Balek and Malek, Nuclear Research Institute Rez pie, and A
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Beahm, Oak Ridge National Laboratory Surface Layer Formation of the French SON68 Nuclear Waste Glass During Vapor E.72 Phase Alteration at 200° C W
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Timmons, and lack L McElroy, Geosafe Corporation The Interaction' Between HI W Glass and Clay: Present Status and Future E.98 E.100 Programme, Pierre Van Iseghem, Kare} Lemmens, Marc Aertsens, Philippe Lolivier, Wei liang, and Pierre De Canniere, SCK CEN, Belgium Serif cation Studies on the Pamela High-Level Waste Glasses, P
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From page 58... ...
C Vitrification of Radioactive Waste: Past Accomplishments and Future Challenges Werner Lutze Center for Radioactive Waste Management (CeRaM)
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From page 59... ...
I Radioactive Waste Forms for the Future, W
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Departmental process, the Department selected borosilicate glass for high level waste immobilization. A number of vitrification processes for low level, mixed, and environmental restoration wastes are in various stages of evaluation, demonstration, or implementation.
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From page 61... ...
The Defense Waste Processing Facility at the Savannah River Site, initiated radioactive activities on March 12, 1996; the first canister of radioactive glass is scheduled to be produced in the very near future. Initiation of radioactive activities at the West Valley Demonstration Project are imminent, with production of the first canister of radioactive glass scheduled for J ate June.
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From page 62... ...
Identification of materials having some potential for vitrification begins by cons~denng the broad categories of existing nuclear wastes or matenals Cat may be declared surplus, which are Vised in Be first column of Table I Uranium malt tailings and enrichment plant tails are excluded because Heir large volume and low toxicity result in essentially no potential for vitof~cation.
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From page 63... ...
E.11 c: ILL m o i_ LO o CL 5 o On A hi: :~: ~r hi: U)
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From page 64... ...
Formulation of Hanford waste glasses can be effectively achieved with the use of mathematical models that relate glass properties to glass composition. The mode} response functions are typically nonlinear because the effects of glass components on key glass properties are interactive.
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From page 65... ...
because several primary crystalline phases appear in Hanford HLW glasses and each of these phases requires a special response function. This puts an extra demand on the amount of measured data required and brings a problem of determining which crystalline phase is primary for a given composition.
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From page 66... ...
, as part of the Civilian Radioactive Waste Management System Management & Opening Contractor, is responsible for designing bow the waste package and He engineered battier system. The goal of the DOE's Yucca Mountain Site Chametelizahon Project is to chamctelize He Yucca Mountain site and design a potential geologic repository for Be safe disposal of SNF and solidified ELBOW.
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From page 67... ...
To accommodate He acceptance and disposal of DOE-owned spent filet, similar performance and compliance issues must be addressed Trough modeling and testing programs specifically oriented towards these materials. To this end, He DOE Offices of Environmental Management and Civilian Radioactive Waste Management have established technical coordinating groups for bow HEW and DOE-o~med SNF which meet on a quarterly basis to monitor interface issues between these programs.
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From page 68... ...
Consideration of all these factors are essential in the development of high integrity, cost-effective waste forms and subsequent systems designed to manage or permanently dispose of the hazardous materials. Using an interdisciplinary approach and building upon the experience and knowledge of classical glass science, complex borosilicate glass systems have been developed which have successfully immobilized the more than 40 elements contained within HEW as well as the large fluctuations in waste composition that can exist.
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From page 69... ...
This will be undertaken by first, providing a brief historical background into the subject, while emphasizing the U.S. HEW program and development of HEW waste glasses.
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From page 70... ...
described. -a r ~ t-~na~iy some results of tests of durability of different glass compositions are In liquid water, there are at least three different processes taking place during reaction with silicate glasses.
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From page 71... ...
Silicate glasses dissolve more rapidly as the pH is increased above 7. These results show that there is a large potential for increasing He durability of glasses for encapsulating radioactive waste.
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From page 72... ...
is internationally accepted as the technology of choice for the immobilization of highly toxic radioactive waste. The French, British, Japanes, and Belgians are ah operating vitrification plants for high level nuclear waste (HEW)
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From page 73... ...
Each of the carusters of simulated waste glass produced was destructively examined, and the results compared to the specifications for the glass product. The results were outstanding all of the glass samples tested were far below the acceptance Bruit, and there was greater than 99% confidence that more Han 99.9 % of He glass produced was acceptable.
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From page 74... ...
Glass compositions have undergone a genesis over the past 15 years in response to concerns about feed streams, processing, and durability. A range of borosilicate compositions has been identified [2]
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From page 75... ...
Nuclear Waste," ASTM C-!
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From page 76... ...
For typical borosilicate waste glasses, such rates are generally slightly higher than the current regulation of one part in 10^5 release per year. Few experiments have addressed this issue.
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From page 77... ...
L., 1994, Effect of surface layers on the dissolution of nuclear waste glasses: Materials Research Society Symposium Proceedings, v.
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From page 78... ...
Rhone Valley Research Center BP 171, 30207 Bagnols-sur-Ceze Cedex, France The long-term durability of radioactive waste glass will be assessed by modeling. A strict methodology is necessary to develop a predictive mode} valid over long time periods, and may be summarized as follows: 2.
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From page 79... ...
A more general rate equation would be necessary to describe nuclear waste glass alteration in any environment. Nevertheless, we consider that the first-order law remains a justified approximation in many environments (including pure water, granite, salt or silica-saturated cIay)
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From page 80... ...
Also, it is not yet possible to include radiolysis in an integrated geochemical model of glass dissolution under near field conditions. This is very critical, as the solution Eh may depend on it.
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From page 81... ...
(2) Behavior of safety relevant radionuclides during glass dissolution Depending on the geochemical environment glass corrosion may or may not be accompanied by transfer of safety relevant radionuclides to a potentially mobile aqueous phase.
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From page 82... ...
There has been considerable effort (see selected references) devoted to the study of the alteration and dissolution of natural glasses in an effort to assess the lone term behavior of nuclear waste glasses.
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From page 83... ...
Natural Glasses: Analogues for Radioactive Waste Forms. MRS Proceedings of "Scientific Basis for Nuclear Waste Management I", 57-68.
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From page 84... ...
This requires the host form to be suitable for transportation and to also allow recovery of the Am and Cm. A glass formulation which is approximately 1000X more durable than the specification for high-level waste glass but selectively attacked by nitric acid was chosen as the optimum form.
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From page 85... ...
to determine the processability and chemical and physical properties of plutonium glasses. Both borosilicate and phosphate glass compositions have been examined.
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From page 86... ...
Nuclear waste containment glasses are for the most part borosilicate glasses, and this critical review was therefore limited to such formulations. The published studies[i 2]
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From page 87... ...
Koyama, "Surface Layer Crystallization of Simulated Waste Glass at Elevated Temperatures", Scientific Basis for Nuclear Waste Management, Materials Research Society Symposium Proceedings, vol.
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From page 88... ...
At ITU, three borosilicate waste glass foes were extensively investigated but some other glasses were also exa7nmed (e.g. the alternative Gennan product SM513 EWIl)
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From page 89... ...
waste glasses was also measured In laboratory-scale drop tests and In fur-scale Mop tests using European standard high level waste camsters [51. Waste glass fracture, aerosol release and activity source term were determined for different impact energies and glass compositions.
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From page 90... ...
Box 999, Mail Stop K2-44 RichIand, WA 99352 USA wj_weber~pnI.gov A key challenge in the permanent disposal of high-level waste (HEW) , plutonium residues/scraps, and excess weapons plutonium in glass waste forms is the development of predictive models of long-term performance that are based on a sound scientific understanding of relevant phenomena.
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From page 91... ...
The dissolution rate of glass waste forms may be affected by radiation-induced defects, phase separation, and changes in chemistry, microstructure, and network bonding. Based on the limited data, it is estimated that radiation-induced increases in leach rates will be no more than a factor of 10, provided there is no radiation-induced phase separation or bubble formation.
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From page 92... ...
In total 34.8 t of solid waste containing 1.49 E12 Bq alpha and 4.09 E14 Bq beta were cemented in 187 200 Arums. Quality Assurance Programme The success of the vitrification operations was mainly the result of the strict follow-up of a quality assurance and control programme, set up in co-operation with the Belgian National Agency for Radioactive Waste and Enriched Fissile Material (known as NIRAS)
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From page 93... ...
(19921. Qualification and characterization programmes for disposal of a glass product resulting from high level waste vitrification in the Pamela installation of Belgoprocess.
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From page 94... ...
Hughes BINNINGER - COGEMA - La Hague From the early days of the development of nuclear energy, France has been concerned with the disposal of radioactive waste, and the containment of fission product procluced in the fires elements during their stay in the reactor core. Laboratory research on containment matrices began in 1957, first with crystalline materials, then with glass - which quickly proved to be more suitable for incorporating the forty-odd elements created by uranium fission (as well as additives and corrosion products resulting from filed reprocessing)
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From page 95... ...
_~1 1 __ _:1~1 ~ ~ _1~ A_ / -- ~ ~ _L _ _1 ~ _ 11 ~ 1 The CCM technique is now reaching maturity; possible applications include not only vitrifying solutions containing fission products but also incineration of combustible waste including plastics and even ion exchange resins. Recent program in implementing units with larger capacities also make the cold crucible melter a serious candidate for vitrifying low and medium level wastes.
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From page 96... ...
One of the primary objectives of the West Valley Demonstration Project tWVDP} is the solidification of approximately 2.3 million liters of high-level radioactive waste tHLW) which resulted from nuclear fuel reprocessing.
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From page 97... ...
Major components within the cell include the ceramic melter, canister turntable, infrared level detection system, remote lid welder, decontamination station, and remote transfer cart. The melter is the primary component of the vitrification process.
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From page 98... ...
The TVF has two main cells, one is a vitrification cell where most of vitrification process equipment such as a receiving vessel and art evaporator treating HLLW, a glass melter, a welder, and the off-gas treatment equipment are installed. This cell incorporates a new concept of fully remote maintenance in accordance with the adoption of large cell, so that the plant availability should be increased and personnel exposure decreased.
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From page 99... ...
Each operation result shows that the TVF has enough performance for the safety and process operation, and also for the quality control of glass products. For the remote maintenance of process equipment in the vitrification cell, the remote maintenance capability by two-anned servo-manioulators and '' ~ t ~ ~ ~ ~ ~ , ~n-ce~ cranes nac been confirmed for act remote equipment more than 1000 objects including a glass melter and the racks mounting the process equipment.
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From page 100... ...
Selection criteria were established for the glass matrix aimed at a waste loading of about 25%. Early work on glasses led to the borosilicate system being chosen on a balance of factors such as durability, chemical stability, corrosiveness and melting temperature.
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From page 101... ...
After approximately ~ hours the glass product is fed into the container situated underneath. Following pouring the container is allowed to cool and a lid is welded on.
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From page 102... ...
Vitrification complex occupies two buildings connected with each other. There are pretreatment solution area as well as off-gases cleaning system in the first building, the second accommodates 2 ceramic melters, a unit for pouring glass melt into canister, a remote welding system and air cooled storage.
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From page 103... ...
N Romanovsky, "Radioactive Waste Management of the Radiochemical Plant Under construction near Krasnoyarsk," SPECTRUM '94, August 14-1 8, Atlanta, GA, v.3, pp.
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From page 104... ...
Since the sulfur solubility is I~m~ted in borosilicate glass, the waste oxide loading of glass product must be limited to 16 wt.%. Even though the content of noble metals is rather low in the waste, Heir presence is still given careful consideration in the melter design.
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From page 105... ...
"An Overview of Vitrification for High-L.eve! Radioactive Waste in China", Proceedings of the 1989 Joint International Waste Management Conference, Kyoto 1989, pp.
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From page 106... ...
. After an extensive testing program, the DWPF recently began radioactive operations with the production of its first canister of radioactive waste glass.
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From page 107... ...
. During the Waste Qualification Runs portion of the test program, fifty-f~ve canisters were filled, over four melter campaigns, with simulated waste glass.
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From page 108... ...
1986~. Experimental studies of the corrosion mechanism of borosilicate nuclear waste glasses up to five years indicate that the glass dissolution continues at a low rate after the solution is saturated with respect silica (Lutze et al.
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From page 109... ...
Though only the Mg-rich smectite was found in the sediments and on the glass surface, it is concluded that the other phases are mainly glass corrosion products. Again, analog corrosion behavior of natural and nuclear waste glasses is emphasized by common alteration phases such as Mg-rich smectite, Sr-rich barite, and cerianite.
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From page 110... ...
Ground samples of different nuclear waste glasses were examined using REM in both virgin and altered forms. The composition of the borosilicate glass samples differed, depending on the laboratories where the glass was prepared.
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From page 111... ...
CONCLUSIONS The temperature dependencies of radon release rate measured during heating and subsequent cooling of the virgin and altered samples of the nuclear waste glasses can be used as fingerprints characterizing morphology and radon permeability of the samples. The systematic expenmental study performed In the frame of the IAEA Coordinated Research Program have resulted in the recommendation of the Radon Emanation Method as a supplementary method for characterization of the alteration product of nuclear waste forms.
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From page 112... ...
Basis for Initiative Vitrification is a desirable treatment option for mixed waste because the vitrified waste forms will resist degradation for the thousands of years necessary to allow decay of the radioactive component while chemically binding both the radioactive and hazardous components in the glass matrix, thus, reducing the threat to human health and the environment. Due to these features, EPA has specified, under the LDR program, vitrification to be the specified (or required)
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From page 113... ...
The Department is pursuing other regulatory initiatives under the The EPA or authorized State would retain control leadership of Susan Jones and Michael Kleinrock, over the vitrification process to assure, through a DOE Office of Waste Management, Office of permit or other environmental compliance Technical Services. Additional information on mechanism, that the process produces a glass DOE regulatory initiatives can be obtained by meeting environmentally acceptable performance contacting Ms.
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From page 114... ...
Incleed plutonium is immisible with many low temperature glass compositions. Crystalline immobilization media, e.
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From page 115... ...
C Sales, Monazite, in: Radioactive wastefonns for the future, edited by W
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From page 116... ...
On October 20, 1995, DOE supplemented the July 1995 report to EPA with a report entitled "Performance Evaluation for RCRA Toxic Metal Disposal in DOE Low-Level Radioactive Waste Disposal Facilities." The basis for DOE's immobilized mixed debris proposal is the combination of the integrity of the encapsulated debris waste form, coupled with the protectiveness of a LLW disposal facility, is protective of human health and the environment. Integrity of the Final Waste Form To ensure mixed debris treated by immobilization and placed in a low-level waste disposal facility is sufficiently protective of human health and the environment, DOE proposed that the final waste form meet or exceed established performance criteria.
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From page 117... ...
Risk-Based Analysis of Low-Level Disposal Facilities In DOE's report, "Performance Evaluation for RCRA Toxic Metal Disposal in DOE Low-Level Radioactive Waste Disposal Facilities." a risk based analysis evaluated the environmental transport of RCRA toxic metals from six DOE LLW disposal sites. The analysis focuses on the toxic metal component of the mixed waste debris (the principal contaminants in DOE's mixed LLW debris)
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From page 118... ...
final water concentrations and density were treateci as independent variables of the hydration process. With empirical linear ant} diffusion rates and laboratory rates as activation energy and diffusion coefficients treated as dependent variables in stepwise regression analysis.
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From page 119... ...
E Durability of Rhyolithic Ol~siclia~ Glass Inferred froin Hydration Dating Research, Scientific Basils for Nuclear Waste Manace~ne~t, Vol.
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From page 120... ...
Pretreatment such as size reduction, debris separation, and drying are unnecessary, which is especially advantageous for highly radioactive wastes, such as spent nuclear fuels; (2) Flexibility - The PAVC process can accept heterogeneous feeds and relatively large debris.
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From page 121... ...
The crystals are tightly bound to the glassy matrix, resulting in good physical integrity and mechanical strength of the waste form. The glassy matrix can immobilize elements that cannot be incorporated into crystalline phases, and therefore offers greater processing flexibility than purely crystalline waste forms, as well.
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From page 122... ...
831-6495 Tel: (423) 574-6783; Email: forsbergcw@,ornI.gov INTRODUCTION A new waste vitrification process, the Glass Material Oxidation and Dissolution System (GMODS)
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From page 123... ...
~_ Lead Product Cyllnder POUR GLASS Boron Oxide ~ ~ ~ blat my,, I F ~ ADD MAKEUP {32O3 · ADD MAKEUP PbO Glass Oxygen · ADD OXYGEN · OXIDIZE LEAD TO PbO FIG. 1 GMODS batch processing of wastes to borosilicate glass.
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From page 124... ...
The mechanism of aqueous corrosion of "R7T7" waste glass have been extensively investigated in the literature.' Vapor phase alteration was used to accelerate the reaction progress of glass corrosion and to develop the characteristic suite of secondary, alteration phases. Additionally, vapor phase alteration will be an important corrosion mechanism of nuclear waste glasses in a hydrologically unsaturated geological repository.
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From page 125... ...
The recrystallization of the B-domains into the A-domain smectites is a critical mechanism for surface layer formation and very important to understanding of the long-term behavior of rare-earths, Zr, and the transition elements. Two crystalline phases, Ag2TeO3 and (Ca,Sr)
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From page 126... ...
. The present paper reviews this field from the perspective of its potential application to assess the long-term stability of various glass forms under consideration for immobilization and disposal of high-level nuclear wastes and excess weapons plutonium.
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From page 127... ...
ions have been recorded in such glasses.5 Me characteristic superoxideion ESR spectrum appears to arise from O2- ions in a disordered alkali peroxide matrix, implying that relatively low pray doses have initiated a decomposition of simple silicate glasses into intimate mixtures of oxygen rich phases and chemically reduced phases. Because alkali peroxides are known6 to spontaneously disproportionate into monoxides and superoxides and the latter in turn are known to disproportionate into peroxides and O2 molecules, this multi-step process may account for observations of bubble formation in electron-, ion- or y-irradiated nuclear waste glasses.7 This kind of decomposition is analogous to the radiation-induced growth of sodium metal colloids and evolution of chlorine in irradiated rock salt.8 In principle, at least, a radically decomposed waste glass hermetically sealed in a steed canister might be vulnerable to chemical explosion.
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From page 128... ...
I, JAPAN. ABSTRACT In recent years, some corrosion tests on actinoids-doped waste glasses have been performed, and leaching behavior of actinoids from the waste glasses has been investigated.
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From page 129... ...
Fig.3. Solution concentrations of Pu and Cm under reducing conditions.
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From page 130... ...
Department of Energy WOES. The resulting acidic high-level liquid radioactive waste ~LW)
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From page 131... ...
· ~ e In the 1 980s, glass ceramic formulations were tested using a hot isostatic press CUP) for high temperature sintering to produce a 70 wt% waste loading form with a 2.6-fold lower volume than the equivalent class waste forms.
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From page 132... ...
Our studies indicate that the natural hydration of glasses can be quantitatively reproduced under accelerated laboratory conditions, when the reaction is dorrunated by a relatively simple process such as the molecular water diffusion. Nine-Year Results from Testing Basaltic and Simulated Waste Glasses We have performed vapor hydration tests on synthetic basaltic and simulated nuclear waste glasses at temperatures ranging from 70 to 250°C for periods of up to 9 years.
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From page 133... ...
(1979) "Natural analogues: analogues for radioactive waste forms," Scientific Basis for Nuclear Waste Management, edited by G.~.
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From page 134... ...
K Bates Chemical Technology Division, Argonne National Laboratory, Argonne, L 60439-4837, mertz @cmt.anI.gov The Tong-term behavior of nuclear waste glass in a geologic repository may require a technical consideration of the role of colloids in the release and transport of radionuclides.
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From page 135... ...
C Buck et al., The Scientific Basis for Nuclear Waste Management XIX, MRS Symposium Proc.
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From page 136... ...
These glasses In the majority of the studies have been based on conventional glass cheesy in which the radioactive waste is added to a glass of known composition and the waste dissolved Into the glass matrix. The use of the higher temperature capability of the DC Arc Melter offers an alternative approach ~ which the waste is melted In the melter and Me composition of the melt mnHifi~1 wish oniv e.nc~u~h additives to form a glass/cera~ruc material.
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From page 137... ...
The types of waste simulants run to date In the melter are summarized as follows: Sod Sod Soil and Metal Soil and Metals Soil and Combustibles Soil and Combustibles Soil and RFP Sludge Soil and RFP Sludge Soil and RFP Sludge Soil and Volatile Metals Soil and Volatile Metals Soil and additives Soil and additives Soil and additives Soil and additives Demolition debris Demolition debris Demolition debris Mixed Waste Simulant The resets of these tests Indicated: INEL Soil-unsubmerged arc INEL Soil-submerged arc INEL Soil and 25~ metal- Mix INEL Soil and 505~0 metal Mix INERT Soil and wood, paper, plastic, cloth and concrete Hospital Ash INEL Soil and REP 745 sludge, Sodium nitrate and Potassium nitrate sludge with Portland Cement INEL Soil and RFP 741 /742 sludge, Metal hydroxide sludges. INEL Soil and RFP 743 sludge, Regal Oil and Micro cell-E INEL Soil and (CsNO3 and Ce(NO3~3~-submerged INEL Soil and (CsNO3 and Ce(NO3~3~unsubmerged South Carolina high Silica soil win fluxing agent Ca(OH)
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From page 139... ...
Shi-Ben Xing Catholic University of America Jacqueline Ruller William Greenman ) GTS Duratek Approximately 230,000 m3 of defense nuclear wastes is stored in underground tanks at the US Department of Energy site in Hanford, Washington.
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From page 140... ...
The amount of water in glasses were measured by Karl Fisher method. The parameters governing uranium solubility in silicate melts were (i)
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From page 141... ...
in the silicate melts also have a strong effect on uranium solubility. These anions act like excess alkalis for the depolymerisation of the silicate melts.
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From page 142... ...
Product Consistency Test (PCT) normalized boron releases as a Unction of glass composition for several simulated waste glass data sets, including ones from Savannah River, West Valley, and Hanford.
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From page 143... ...
Table I R2 Statisticsta' for FEH, FOM, and SOM Models Fitted to Several Simulated Waste Glass Composition/Durability Data Sets Data Set(b)
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From page 144... ...
The compositional stability regimes for homogeneous glass, glass-ceramic and ceramic are a function of waste loading at a specified temperature. The microstructural characteristics and leach rates of these regimes are discussed in this paper.
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From page 145... ...
Possibly, development of altered Avers glass corrosion reactions. The ~;t;c~n~1 1v examined in
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From page 146... ...
On the other hand, because it chose to apply cementitious solidification technologies instead, Great Britain is now rapidly converting its accumulation of equally-radioactive historic radwastes to competent waste forms. This caner discusse.s how cementitin''.e warm '_ 1 ~Are - ~.
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From page 147... ...
Vitrification of Radwasfe Concretes,·n Scientific Basis for Nuclear Waste Management, XIX, eds.
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From page 148... ...
Ojovan Scientific and Industrial Association "Radon" The 7-th Rostovsky Lane, 2/14, Moscow, 119121, Russia, fax (095) 248 1941, E-mail oj~nporadon.msk.ru Waste glass, that contain real intermediate level radioactive waste from nuclear power plants, was obtained at experimental vitrification plant at SIA "Radon".
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From page 149... ...
Lodding, "Waste glass alteration processes, surface layer evolution and rate limiting steps," Mat.
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From page 150... ...
However, that approach is being supplemented with staged approaches wherein stored wastes or wastes Tom other on-site locations are positioned In cells for treatment. The ISV process produces vitrified products that exhibit a variety of appearances and textures when perfonned on different soil and waste matrices.
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From page 151... ...
The resulting vivified products included silica rich glass phases Intermixed with crystalline phases including wolIaston~te, diopside and cr~stobalite. The localized compositions around the crystalline growths were evaluated by electron microprobe analyses.
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From page 152... ...
We evidence the yet important role of the glass composition: the current borosilicate glasses such as the R7T7 one corrode madly congruently in Boom clay, whereas the high Allot Pamela glass corrodes by selective dissolution. We have confirmed the fundamental difference in glass dissolution by profile analysis using SIMS (secondary ion mass spectroscopy)
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From page 153... ...
Specific laboratory tests will be performed to determine specific parameters required by the model, such as the diffusion coefficient of Si through the glass surface layer and through the clay, the porosity of the surface layer.
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From page 154... ...
. This paper deals with the verification programme for the high-level waste glasses produced in the PAMEAL vitrification furnace, operated by DWK/Belgoprocess.
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From page 155... ...
The paper will review all data generated on two glass compositions (SM513 and SM527) , with attention to the experimental procedures and the reliability of the data.
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From page 156... ...
Hart and A Jostsons, Australian Nuclear Science and Technology Organisation kph~ansto.gov.au It has been noted that given the compositional diversity of nuclear waste and the variations in potential repository geologies in different countries, it is important to have a "menu" of waste forms so that one is able to choose the waste form that best suits the type of waste and the geology of the repository (Lutze and Ewing, ~ 988~.
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From page 157... ...
The work carried out thus far has establisher! that Synroc is a viable alternative for disposal of nuclear waste.
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From page 159... ...
trifunac@anIch~n.chm.anI.gov E.107 Studies of chemical mechanisms of radiation effects in solids address the need to provide a scientific basis for predicting the performance of solid radioactive waste forms. In the Radiation and Photochemistry Group at Argonne National Laboratory many state-of the-art capabilities have been developed to identify reactive intermediates and elucidate radiolysis mechanisms in solids.
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From page 160... ...
This proposal includes glass samples doped with large amounts of alpha emitters. This is consistent with the recommendations of an International Workshop on in-situ testing, of nuclear waste glasses tI]
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From page 161... ...
Workshop "In-situ testing of radioactive waste forms and engineered barriers", FUR 15629 (pre-print)
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