Hostname: page-component-848d4c4894-r5zm4 Total loading time: 0 Render date: 2024-06-25T08:04:11.718Z Has data issue: false hasContentIssue false

Diffusion of Iodine and Technetium-99 Through Waste Encasement Concrete and Unsaturated Soil Fill Material

Published online by Cambridge University Press:  17 March 2011

Shas V. Mattigod
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington, 99352, U.S.A, shas.mattigod@pnl.gov
Greg A. Whyatt
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington, 99352, U.S.A
J. R. Serne
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington, 99352, U.S.A
Marcus I. Wood
Affiliation:
Fluor Hanford Inc., Richland, Washington, 99352, U.S.A
Get access

Abstract

An assessment of long-term performance of low level waste-enclosing cement grouts requires diffusivity data for radionuclide species such as, 129I and 99Tc. The diffusivity of radionuclides in soil and concrete media was collected by conducting soil-soil and concrete-soil half-cell experiments. The soil diffusivity coefficients for iodide were 7.03 × 10−8 cm2/s and 2.42 × 10−7cm2/s for soils at 4% and 7% moisture contents, respectively. Iodide diffusivity in soil is a function of moisture content and is about an order of magnitude slower at lower moisture content. The soil diffusivity coefficients for 99Tc were 5.89±0.80 × 10−8 cm2/s (4% moisture content) and 2.04±0.57 × 10−7 cm2/s (7% moisture content), respectively. The soil diffusivity of iodide and 99Tc were similar in magnitude at both water contents, indicating that these ions have similar diffusion mechanisms in unsaturated coarse-textured Hanford soil. The diffusivity of iodide in concrete ranged from 2.07 × 10−14 cm2/s (4% soil moisture content) to 1.31 × 10−12 cm2/s (7% soil moisture content), indicating that under unsaturated soil moisture conditions, iodide diffusivity is highly sensitive to changing soil moisture conditions. Depending on the soil moisture content, the diffusivity of 99Tc in concrete ranged from 4.54 × 10−13 cm2/s to 8.02 × 10−12 cm2/s. At 4% soil moisture content, iodide diffused about 20 times more slowly than 99Tc, and at 7% soil moisture content, iodide in concrete diffused about 6 times slower than 99Tc.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Wood, M. I., Khaleel, R., Rittman, P. D., Lu, A. H., Finfrock, S., Serne, R. J. and Cantrell, K. J... Performance Assessment for the Disposal of Low-Level Waste in the 218-W-5 Burial Ground., WHC EP-0645, Westinghouse Hanford Company, Richland, Washington (1995).Google Scholar
2. Mann, F. M., Puigh, R. J. II, Rittmann, P. D., Kline, N. W., Voogd, J. A., Chen, Y., Eiholzer, C. R., Kincaid, C. T., McGrail, B. P., Lu, A. H., Williamson, G. F., Brown, N. R. and LaMont, P. E.. Hanford Immobilized Low-Activity Tank Waste Performance Assessment. DOE/RL-97-69, Rev. 0, U.S. Department of Energy, Richland, Washington (1998).Google Scholar
3. Serne, R. J., Martin, W. J., LeGore, V. L., Lindenmeier, C. W., McLaurine, S. B., Martin, P. F. C. and Lokken, R.O.. Leach Tests on Grouts Made with Actual and Trace Metal-Spiked Synthetic Phosphate/Sulfate Waste. PNL-7121. Pacific Northwest Laboratory, Richland, Washington (1989).Google Scholar
4. Serne, R. J., Lokken, R. O. and Criscenti, L. J., Waste Management, 12, 271287 (1992).Google Scholar
5. Serne, R. J., Ames, L. L., Martin, P. F., LeGore, V. L., Lindenmeier, C. W. and Phillips, S. J.. Leach Testing of in Situ Stabilization Grouts Containing Additives to Sequester Contaminants, PNL-84 Pacific Northwest Laboratory, Richland, Washington (1992).Google Scholar
6. Serne, R. J., Martin, W. J. and LeGore, V. L.. Leach Test of Cladding Removal Waste Grout Using Hanford Groundwater. PNL-10745, Pacific Northwest Laboratory, Richland, Washington (1995).Google Scholar
7. Crank, J.,. The Mathematics of Diffusion. Second Edition. Oxford University Press, New York (1975).Google Scholar
8. Finney, D. J., Probit Analysis, Third edition, Cambridge University Press, New York (1971)Google Scholar
9. Brown, D. A., Fulton, B. E. and Phillips, R. E., Soil Sci. Soc. Am. Proc., 28, 628632 (1964).Google Scholar
10. Lamar, D. A., Measurement of Nitrate Diffusivity in Hanford Sediments via the Half-Cell Method Letter Report to Westinghouse Hanford Company, Pacific Northwest National Laboratory, Richland, Washington (1989).Google Scholar
11. Martin, P. F., Serne, R. J., Legore, V. L and Lindenmeier, C. W. Status Report on Ionic Diffusion Through Asphalt. Letter Report to Westinghouse Hanford Company. HGTP-93-0602-01. Pacific Northwest Laboratory, Richland, Washington (1994).Google Scholar
12. Crane, P. J., Benny, H. L. and Wood, M. I.. Physical Modeling of Contaminant Diffusion from Cementitious Waste Form. WHC-SA-1345-FP. Westinghouse Hanford Company, Richland, Washington (1992).Google Scholar
13. Pourbaix, M., Atlas of Electrochemical Equilibria. Pergamon Press, Oxford, England (1966).Google Scholar
14. Atkinson, A. and Nickerson, A. K.. Nucl. Tec. 81, 100113 (1988).Google Scholar