Hostname: page-component-848d4c4894-x5gtn Total loading time: 0 Render date: 2024-05-15T14:02:09.362Z Has data issue: false hasContentIssue false

Solubility Data for U(VI) Hydroxide And Np(IV) Hydrous Oxide:Application of MCC-3 Methodology

Published online by Cambridge University Press:  26 February 2011

Kenneth M. Krupka
Affiliation:
Geosciences Research and Engineering Department, Pacific Northwest Laboratory, PO Box 999, Richland, WA 99352, USA
Dhanpat Rai
Affiliation:
Geosciences Research and Engineering Department, Pacific Northwest Laboratory, PO Box 999, Richland, WA 99352, USA
Robert W. Fulton
Affiliation:
Geosciences Research and Engineering Department, Pacific Northwest Laboratory, PO Box 999, Richland, WA 99352, USA
Richard G. Strickert
Affiliation:
Geosciences Research and Engineering Department, Pacific Northwest Laboratory, PO Box 999, Richland, WA 99352, USA
Get access

Abstract

Experiments based on a modified MCC-3S test method were conducted to investigate the solubility of U(VI) hydroxide (the mineral schoepite) and Np(IV) hydrous oxide at ambient temperature. The solubility of U(VI) hydroxide was investigated in carbonate-free, oxidizing aqueous solutions in the pH range of 3 to 11. The measured concentrations of dissolved U confirm the amphoteric behavior of U(VI) hydroxide solid and the importance of anionic U(VI) hydroxyl complexes in accurately calculating the solubilities of U(VI) solids under basic pH conditions. The effect of fluoride complexation on the solubility of Np(IV) hydrous oxide was studied in carbonatefree, near-neutral to alkaline solutions that contained 100 ppm total F. For solutions in which sodium dithionite (Na2 S2O4) and metallic Fe were used as reducing agents, the addition of 100 ppm F had no measurable effect on the solubility of Np(IV) hydrous oxide.

Type
Research Article
Copyright
Copyright © Materials Research Society 1985

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] Allard, B., “Solubilities of actinides in neutral or basic solutions,” in Actinides in Perspective, edited by Edelstein, N.M. (Pergamon Press, New York, 1982), pp. 553580.Google Scholar
[2] Wood, B.J. and Rai, Dhanpat, Nuclear Waste Isolation: Actinide Containmentin Geologic Repositories, PNL-SA- 9549, Pacific Northwest Laboratory, Richland, Washington (1981).Google Scholar
[3] Thompson, F.L., Dove, F.H., and Krupka, K.M., Preliminary Upper-Bound Consequence Analysis for a Waste Repository at Yucca Mountain, Nevada, PNL-5104 (SAND83-7475), Prepared for Sandia National Laboratories by Pacific Northwest Laboratory, Richland, Washington (1984).Google Scholar
[4] Wang, R., Spent Fuel Special Studies Progress Report: Probable Mechanisms for Oxidation and Dissolution of Single-Crystal UO2 Surfaces, PNL-3566, Pacific Northwest Laboratory, Richland, Washington (1981).Google Scholar
[5] Vandergraaf, T.T., Leaching of Irradiated UO2 Fuel, Technical Record TR-100, Whiteshell Nuclear Research Establishment, Pinawa, Manitoba, Canada (1980).Google Scholar
[6] Kuhn, W.L., “Development of a source term for radionuclide release from spent fuel in a basalt repository,” Nuclear Chem. Waste Management 2, 253257 (1981).Google Scholar
[7] Krupka, K.M., Jenne, E.A., and Deutsch, W.J., Validation of the WATEQ4 Geochemical Model for Uranium, PNL-4333, Pacific Northwest Laboratory, Richland, Washington, (1983).Google Scholar
[8] Langmuir, D., “Uranium solution-mineral equilibria at low temperatures with applications to sedimentary ore deposits,” Geochim. Cosmo. Acta 42, 547569 (1978).CrossRefGoogle Scholar
[9] Lemire, R.L. and Tremaine, P.R., “Uranium and plutonium equilibria in aqueous solutions to 200°C,” J. Chem. Eng. Data 25, 361370 (1980).CrossRefGoogle Scholar
[10] Cleveland, J.M., Rees, T.F., and Nash, K.L., “Ground-water composition and its relationship to plutonium transport processes”, in Plutonium Chemistry, edited by Carnell, W. T. and Choppin, G. R., ACS Symposium Series 215 (American Chemical Society, Washington, D.C., 1983), pp. 335346.Google Scholar
[11] Rees, T.F., Cleveland, J.M., and Nash, K.L., “Neptunium and americium speciation in selected basalt, granite, shale and tuff ground waters,” presented at the American Chemical Society Symposium on Geochemical Behavior of Disposed Radioactive Waste, March 20–25, 1983, Seattle, Washington, 1983.Google Scholar
[12] Cleveland, J.M., Rees, T.F., and Nash, K.L., “Neptunium and americium speciation in selected basalt, granite, shale, and tuff ground waters,” Science 221, 271273 (1983).Google Scholar
[13] Material Characterization Center, Test Methods Submitted for Nuclear Waste Materials Handbook, PNL-3990, Pacific Northwest Laboratory, Richland, Washington (1984).Google Scholar
[14] Maya, L. and Begun, G.M., “A Raman spectoscopy study of hydroxo and carbonato species of the uranyl (VI) ion,” J. Inorg. Nucl. Chem. 43, 28272832 (1981).Google Scholar
[15] Hemingway, B.S., Thermodynamic Properties of Selected Uranium Compounds and Aqueous Species at 298.15 K and 1 Bar and at Higher Temperatures– Preliminary Models for the Origin of Coffinite Deposits, Open-File Report 82–619, U.S. Geological Survey, Reston, Virginia (1982).Google Scholar
[16] Robbins, J.C., “Field technique for the measurement of uranium in natural waters,” CIM Bulletin 793, 6167 (1978).Google Scholar
[17] Rai, Dhanpat and Ryan, J.L., Neptunium (IV) Hydrous Oxide Solubility Under Reducing and Carbonate Conditions, PNL-SA-12096, Pacific Northwest Laboratory, Richland, Washington (1984) (Inorganic Chemistry - in press).Google Scholar
[18] Sylva, R.N. and Davidson, M.R., “The hydrolysis of metal ions. Part 2. Dioxouranium(VI),” J. Chem. Soc., Dalton Trans. 465–471 (1979).Google Scholar
[19] Felmy, A.R., Girvin, D.C., and Jenne, E.A., MINTEQ–A Computer Program for Calculating Aqueous Geochemical Equilibria. EPA-600/3-84-032 (NTIS PB84-157148), Prepared by Battelle, Pacific Northwest Laboratories (Richland, Washington) for the U.S. Environmental Protection Agency (Athens, Georgia) (1984).Google Scholar
[20] Strickert, R.G., Rai, Dhanpat, and Fulton, R.W., “Effect of aging on the solubility and crystallinity of Np(IV) hydrous oxide,” in Geochemical Behavior of Disposed Radioactive Waste, edited by Barney, G. S., Navratil, J. D., and Schulz, W. W., ACS Symposium Series 246 (American Chemical Society, Washington, D. C., 1983), pp. 135–14Google Scholar