High-level nuclear waste glasses

This section is primarily intended to show that the relevant combination of the intrinsic physico-chemical and microscopic characteristics of HT materials, their behaviour under aggressive conditions of corrosion, and their modelled thermodynamic stability, yields a sound composite picture of these materials. On the basis of the knowledge acquired over decades on high-level nuclear waste glasses (Vernaz Dussosoy 1992 Bates et al. 1994 Thomassin 1995, 1996 Ewing 1996), these are the key parameters that may drastically influence the long-term durability of HT materials. 

K.E. Spear, T.M. Besmann, and E.C. Beahm, Thermochemical modeling of glass application to high-level nuclear waste glass, MRS Bulletin 24 (1999) 37 4. 

Susman S., Volin K.J., Lieberman R.C., Gwanmesia G.D., Wang Y. Structural changes in irreversibly densified fused silica Implications for the chemical resistance of high level nuclear waste glasses. Phys. Chem. Glasses 1990 31 144-150... 

The reaction proces.ses can be described by a combination of results from leach tests and SIMS. The nominal composition and leach rates (g in - d" ) of a glass formulation, PNL 76-68 (Pacific North-West Laboratories), used as the. standard high-level nuclear waste glass matrix [4], are shown in Table 4. The definition of leach rate u.sed normalizes the loss (in g) to the proportion of that element in the nominal bulk composition. It will be seen that the leach rates for Cs, Na, Mo, Si and B exceeded the overall rate of mass loss from the gla.ss surface, whereas the elements Fe, Zn and Ti did not show significant loss to solution under these conditions. There were also several elements, e.g.. Ca. Ba, Cd and Sr, that were neither rapidly leached nor apparently retained in the surface layers. Studies described in the above-mentioned reviews, using XPS, FTIR, SIMS, SEM and dissolution rates, have established clearly that the primary reaction occurring in solution is the bond-breaking attack by OH at Si (or Al and... 

Cunnane, J. C., Bates, J. K. et al. 1993. High-level nuclear-waste borosilicate glass. In Interrante, C. G. Pabalan, R. T. (eds) Scientific Basis for Nuclear Waste Management XVI. Materials Research Society Symposia Proceedings, 294, 225-232. 

Sprouli., J. F., Marra, S. L. Jantzen, C. M. 1994. High-level radioactive waste glass production and product description. In Barkatt, A. Van Konynenbolrg, R. A. (eds) Scientific Basis for Nuclear Waste Management XVII. Materials Research Society Symposia Proceedings, 333, 15-25. 

Sales BC, Boatner LA (1984) Lead-iron phosphate glass a stable storage medinm for high-level nuclear waste. Science 226 45-48... 

Remote (standoff) LIBS systems have been built by Applied Photonics Ltd. with a range capability of >100 m for defense departments. They also built a transportable standoff LIBS with a 20 m range to characterize radioactive materials in a hot cell at the Sellafield, UK, high-level nuclear waste vitrification plant by directing the laser beam through the lead-glass window of the cell. LIBS is an excellent tool for remote and in situ detection of uranium oxide fuel located in hard-to-reach... 

Fig. 6.21 High level nuclear waste body composed of solid-waste form (glass), canister, overpack and backfill and buffer disposed deep underground...

T. Okura, N. Yoshida, Immobilization of Simulated High Level Nuclear Wastes with Li20-Ce02-Fe203-P20s Glasses, World Academy of Sci., Eng. Technol. 68 (2012) 265-270. 

Grambow, B. 1991. What do we know about nuclear waste glass performance in the repository near field In Sellin, P., Apted, M. Gago, J. (eds) Proceedings Technical Workshop on Near-Field Performance Assessment for High-Level Wastes, Madrid, Spain. SKB Technical Report 91-59. Stockholm, Sweden, 25-49. 

Van Geel, J., et al. Solidification of High-Level Liquid Waste of Phosphate Glass-Metal Matrix Blocks, Proceedings of the Management of Radioactive Wastes from the Nuclear Fuel Cycle, vol. 1, International Atomic Energy Agency, Vienna, 1976, p. 341. 

High-level radioactive waste (HLW) will be converted from an alkaline slurry to a durable borosilicate glass in the Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP) in South Carolina [17]. This waste is the residue from thirty years of reprocessing of irradiated nuclear fuels for national defense purposes and is currently stored in large carbon-steel tanks. 

Heimann, R.B. (1987) A statistical approach to evaluating durability of a simulated nuclear waste glass, in The Geological Disposal of High-Level Radioactive Wastes (ed. D.G. Brookins), Theophrastus Publ., S.A., Athens, Greece, pp. 181-205. 

Scholze, H., Conradt, R., Engelke, H. Roggendorf, H. 1982. Determination of the corrosion mechanisms of high-level waste containing glass. In Lutze, W. (ed) Scientific Basis for Nuclear Waste Management V. Materials Research Society Symposia Proceedings, 11, 173-180. 

In the past ten years the number of chemistry-related research problems in the nuclear industry has increased dramatically. Many of these are related to surface or interfacial chemistry. Some applications are reviewed in the areas of waste management, activity transport in coolants, fuel fabrication, component development, reactor safety studies, and fuel reprocessing. Three recent studies in surface analysis are discussed in further detail in this paper. The first concerns the initial corrosion mechanisms of borosilicate glass used in high level waste encapsulation. The second deals with the effects of residual chloride contamination on nuclear reactor contaminants. Finally, some surface studies of the high temperature oxidation of Alloys 600 and 800 are outlined such characterizations are part of the effort to develop more protective surface films for nuclear reactor applications. ... 

In the case of the disposal of high-level light water reactor waste, these wastes intrinsically contain up to 35 wt % rare-earth oxides that could be directly converted to form part of the monazite host matrix. Because Ewing and Wang (this volume) have provided a comparison of the properties of monazite-based waste forms to those of other crystalline host media and nuclear waste phosphate glasses, no further details regarding this application of the rare-earth orthophosphates will be given here. 

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