Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T02:26:27.419Z Has data issue: false hasContentIssue false
  • English
  • Français

Neptunium Incorporation into Uranium(Vi) Compounds formed During Aqueous Corrosion of Neptunium-Bearing Uranium Oxides

Published online by Cambridge University Press:  21 March 2011

Robert J. Finch ,
Jeffery A. Fortner ,
Edgar C. Buck  and
Stephen F. Wol
Robert J. Finch
Affiliation:
Chemical Technology Division, Argonne National Laboratory, Argonne, IL 60439, USA
Jeffery A. Fortner
Affiliation:
Chemical Technology Division, Argonne National Laboratory, Argonne, IL 60439, USA
Get access

Abstract

We report results of experimental studies on the behavior of Np during aqueous corrosion of unirradiated Np-bearing U oxides. Np-doped U oxides were reacted in humid air at 90°C and 150°C for several weeks within sealed stainless-steel vessels. Reacted solids were examined by scanning and transmission electron microscopies (SEM and TEM), electron energy-loss spectroscopy (EELS), and X-ray powder diffraction (XRD). Dehydrated schoepite, (UO2)O0.25-z(OH)1.5+2z (0 ≤z ≤0.15), is the predominant U(VI) compound formed in these experiments. Preliminary EELS analysis on crushed grains verify that dehydrated schoepite formed at 150°C contains up to approximately 2 wt.% Np, corresponding to a maximum Np:U molar ratio of approximately 1:40. These are maximum values because the degree to which surface-sorbed Np is present on the grains analyzed is not yet known. Crystalline NpO2 also precipitated during these experiments, and the concentration of Np in dehydrated schoepite may represent the maximum amount of Np that can be incorporated into dehydrated schoepite under the experimental conditions.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 713: Symposium JJ – Scientific Basis for Nuclear Waste Management XXV , 2002 , JJ11.63
Copyright
Copyright © Materials Research Society 2002

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

REFERENCES

1. U. S. Department of Energy, office of Civilian Radioactive Waste Management: Viability Assessment of a Repository at Yucca Mountain. Total System Performance Assessment. Volume 3. DOE/RW-0508 (USDOE OCRWM, Yucca Mountain Site Characterization office, North Las Vegas, Nevada, 1998).Google Scholar
2. Efurd, D. W., Runde, W., Banar, J. C., Janecky, D. R., Kaszuba, J. P., Palmer, P. D., Roensch, F. R., Tait, D., Environ. Sci. Technol. 32, 3893 (1998).Google Scholar
3. Finn, P. A., Wronkiewicz, D. J., Finch, R. J., Hoh, J. C., Mertz, C. J., Emery, J. W., Buck, E. C., Fortner, J. A., Wolf, S. F., Neimark, L.A., Bates, J.K, Yucca Mountain Project – Argonne National Laboratory, Annual Progress Report, FY 1997 for Activity WP 1221. Argonne Technical Report ANL-98/12 (June 1998).Google Scholar
4. Finch, R. J., Buck, E.C., Finn, P.A., Bates, J.K. in Scientific Basis for Nuclear Waste Management XXII, edited by Wronkiewicz, D.J. and Lee, J. (Mater. Res. Soc. Proc. 556, Warrendale, PA) pp. 431–438.Google Scholar
5. Burns, P. C., Ewing, R. C., Miller, M. L., J. Nucl. Mater. 245, 1 (1997).Google Scholar
6. Wronkiewicz, D. J., Bates, J.K., Gerding, T.J., Veleckis, E., Tani, B., J. Nucl. Mater. 190, 107 (1992).Google Scholar
7. Finch, R. J. and Murakami, T. in Uranium: Mineralogy, Geochemistry and the Environment, edited by Burns, P. C. and Finch, R. J. (Reviews in Mineralogy 38, Min. Soc. Amer., Washington, D.C. 1999) pp. 91–179.Google Scholar
8. Finch, R. J., Suksi, J., Rasilainen, K., Ewing, R.C. in Scientific Basis for Nuclear Waste Management XIX, edited by Murphy, W.M. & Knecht, D.A. (Mater. Res. Soc. Proc. 412, Warrendale, PA, 1996) pp. 823–830.Google Scholar
9. Buck, E. C., Finch, R. J., Finn, P. A., Bates, J. K., in Scientific Basis for Nuclear Waste Management XXI, edited by McKinley, I. G. and McCombie, C. (Mater. Res. Soc. Proc. 506, Warrendale, PA, 1998) pp. 87–94.Google Scholar
10. Chen, Y., Siegmann, E., Matie, P., McNeish, J., Sevougian, S.D., andrews, R., in Scientific Basis for Nuclear Waste Management XXI, edited by McKinley, I. G. and McCombie, C. (Mater. Res. Soc. Proc. 506, Warrendale, PA, 1998) pp. 474–478.Google Scholar
11. Finch, R. J. and Cunnane, J. C., in Proceedings of the Ninth International Conference on High-Level Radioactive Waste Management, Las Vegas, Nevada, (American Nuclear Society, Lagrange Park, IL, 2001).Google Scholar
12. Kaszuba, J. P. and Runde, W. H., Environ. Sci. Technol. 33, 4427 (1999).Google Scholar
13. Kropf, A. J., Finch, R. J., Conner, C., Karanfil, C., Chapman, L. D., Serge, C., Terry, J., A Silicon Bent Crystal Analyzer as an Energy Bandpass Filter for Fluorescence XAFS. Advanced Photon Source Activity Report 2000 (Argonne National Laboratory, April 2001).Google Scholar
14. Wruck, D.A., Brachmann, A., Sylwester, E.R., Allen, P.G., Palmer, C.E.A.. Sorption of Np(V) by U(VI) Hydroxide Solids. Lawrence Livermore National Laboratory Preprint UCRL-JC-135791 (Also presented at Migration '99: Seventh International Conference on the Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere, Incline Village, Lake Tahoe, Nevada/California, September 1999, Abstract PA1–18, p.31).Google Scholar