Leaching from Cementitious Waste Forms in Belowground Vaults
Publication: Journal of Environmental Engineering
Volume 120, Issue 6
Abstract
Solidification and/or stabilization with cementitious materials prior to burial is one option for disposal of liquid hazardous and radioactive wastes. A common design for disposal of cementitious waste forms is to pour the material into large belowground vaults. The leaching performance of partially degraded monolithic vaults is examined quantitatively for facilities located in humid to semiarid climates. Development of perched water on the vault roof leading to fracture flow through the structure is predicted for a wide range of climate and design conditions. Leaching controlled by diffusion in matrix blocks out to fractures is examined parametrically in relation to water flux rate and crack spacing. Depending upon the parameters examined, release rate may be controlled by water flux rate (advection controlled) or diffusion. Under some circumstances, contaminant release rates and exit concentrations are predicted to be inversely related. In this situation, minimization of release does not result in the lowest predicted groundwater concentrations below the vault.
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References
1.
Atkins, M., and Glasser, F. P. (1992). “Application of portland cement‐based materials to radioactive waste immobilization.” Waste Mgmt., 12, 105–131.
2.
Atkinson, A. (1985). “The time dependence of pH within a repository for radioactive waste disposal.” AERE Harwell Report No. DOE/RW/85.062, Harwell, U.K.
3.
Atkinson, A., Goult, D. J., and Hearne, J. A. (1984). “An assessment of the long‐term durability of concrete in radioactive waste repositories.” AERE‐R11465, Harwell, U.K.
4.
Barth, E. F. (1990). “An overview of the history, present status, and future direction of solidification/stabilization technologies for hazardous waste treatment.” J. Hazardous Mat., Vol. 24, 103–109.
5.
Bažant, Z. P., and Oh, B. H. (1983). “Spacing of cracks in reinforced concrete.” J. Struct. Engrg., ASCE, 109(9), 2066–2085.
6.
Broderson, K. (1992). “Leaching due to hygroscopic water uptake in cemented waste containing soluble salts.” Waste Mgmt., 12, 261–269.
7.
Brooks, R. H., and Corey, A. T. (1964). “Hydraulic properties of porous media.” Hydrology Paper No. 3, Colorado State Univ., Ft. Collins, Colo.
8.
“Causes, evaluation, and repair of cracks in concrete structures.” (1984). ACI J., (May–June), 211–230.
9.
Clifton, J. R., and Knab, L. I. (1989). “Service life of concrete.” NUREG/CR‐5466.
10.
Conca, J. L. (1990). “Diffusion barrier transport properties of unsaturated paintbrush tuff rubble backfill.” Proc. Topical Meeting on High Level Radioactive Waste Mgmt., Vol. 1, American Nuclear Society, 394–401.
11.
Conca, J. L., and Wright, J. (1991). “Aqueous diffusion coefficients in unsaturated materials.” Materials Res. Soc. Symp. Proc., Materials Research Society, Pittsburgh, Pa., 212, 879–884.
12.
Concrete manual. (1988). 8th ed., U.S. Government Printing Office, Washington, D.C.
13.
Dian, J. (1988). Condensation and isothermal water transfer in cement mortar, part I — Pore size distribution, equilibrium water concensation and imbibition. Transport in Porous Media, Vol. 3, 563–589.
14.
“Effect of restraint, volume change, and reinforcement on cracking of mass concrete.” (1990). ACI Mat. J., 271–295.
15.
Gilliam, T. M., Spence, R. D., Bostick, W. D., and Shoemaker, J. L. (1990). “Solidification/stabilization of technetium in cement‐based grouts.” J. Hazardous Mat., 24, 189–197.
16.
Guppy, R. (1988). “Autogeneous healing of cracks in concrete and its relevance to radwaste repositories.” NSS/R‐105, DE88 753994, Nirex, U.K.
17.
Malek, R. I. A., Roy, D. M., Licastro, P. H., and Langton, C. A. (1986). “Slag cement—low level radioactive wasteforms at Savannah River plant.” Am. Ceram. Soc. Bull., 65(12), 1578–1583.
18.
Mitchell, J. K. (1976). Fundamentals of soil behavior. John Wiley & Sons, New York, N.Y.
19.
Oblath, S. B. (1989). “Leaching from solidified wasteforms under saturated and unsaturated conditions.” Envir. Sci. Technol., 23(9), 1098–1102.
20.
Rasmusen, A., and Neretnieks, I. (1981). “Migration of radionuclides in fissured rock: the influence of micropore diffusion and longitudinal dispersion.” J. Geophysical Res., 86(B5), 3749–3758.
21.
Serne, R. J., and Wood, M. I. (1990). “Hanford waste‐form release and sediment interaction, a status report with rationale and recommendations for additional studies.” PNL‐7297, UC‐512, Battelle, Pacific Northwest Lab, Richland, Wash.
22.
Serne, R. J., Lokken, R. O., and Criscenti, L. J. (1992). “Characterization of grouted low‐level waste to support performance assesment.” Waste Mgmt., 12, 271–287.
23.
Seveque, J. L., de Cayeux, M. D., Elert, M., and Nouguier, H. (1992). “Mathematical modelling of radioactive waste leaching.” Cement and Concrete Res., 22, 477–488.
24.
Smith, R. W., and Walton, J. C. (1993). “The role of oxygen diffusion in the release of technetium from reducing cementitious waste forms.” Mat. Res. Soc. Symp. Proc., Materials Research Society, Pittsburgh, Pa., 294, 247–253.
25.
Ross, B. (1990). “The diversion capacity of capillary barriers.” Water Resour. Res., 26(10), 2625–2629.
26.
Soundararajan, R. (1990). “An overview of present day immobilization technologies.” J. Hazardous Materials, 24, 199–212.
27.
Walton, J. C., and Seitz, R. R. (1992). “Fluid flow through fractures in below ground concrete vaults.” Waste Mgmt. 12, 179–187.
28.
Walton, J. C. (1991). “Fluid flow and placement of concrete vaults in the saturated or unsaturated zone.” Waste Mgmt., 11, 3–10.
29.
Walton, J. C., Plansky, L. E., and Smith, R. W. (1990). “Models for estimation of service life of concrete barriers in low‐level radioactive waste disposal.” NUREG/CR‐5542.
30.
Wösten, J. H. M., and van Genuchten, M. Th. (1988). “Using texture and other soil properties to predict the unsaturated soil hydraulic functions.” Soil Sci. Soc. Am. J., 52, 1762–1770.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 120 • Issue 6 • November 1994
Pages: 1507 - 1523
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: Jan 4, 1993
Published online: Nov 1, 1994
Published in print: Nov 1994
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