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Actinides and radiation effects: impact on the back-end of the nuclear fuel cycle

Published online by Cambridge University Press:  05 July 2018

R. C. Ewing*
Affiliation:
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109-1005, USA Department of Materials Science & Engineering, University of Michigan, Ann Arbor, Michigan 48109-1005, USA Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-1005, USA
*

Abstract

During the past 70 years, more than 2000 metric tonnes of Pu, and substantial quantities of the ‘minor’ actinides such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g. 239Pu), a source of fissile material for nuclear weapons (e.g. 239Pu and 2Np), and of environmental concern because of their long half-lives and radiotoxicity (e.g. 239Pu and 237Np). There are two basic strategies for the disposition of these transuranium elements: (1) to ‘burn’ or fission the actinides using nuclear reactors or accelerators; (2) to dispose of the actinides directly as spent nuclear fuel or to ‘sequester’ the actinides in chemically durable, radiation-resistant materials that are also suitable for geological disposal. For the latter strategy, there has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A2B2Oi (A = rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of α-decay event damage. Recent developments in the understanding of the properties of actinide-bearing solids have opened up new possibilities for the design of advanced nuclear materials that can be used as fuels and waste forms. As an example, the amount of radiation damage that accumulates over time can be controlled by the selection of an appropriate composition for the pyrochlore and a consideration of the thermal environment of disposal. In the case of deep borehole disposal (3—5 km), the natural geothermal gradient may provide enough heat to reduce the amount of accumulated radiation damage by thermal annealing.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2011

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References

Albright, D., Berkhout, F. and Walker, W. (1997) Plutonium and Highly Enriched Uranium 1996 World Inventories, Capabilities and Policies. Oxford University Press, New York, 502 pp.Google Scholar
Atencio, D., Andrade, M.B., Christy, A.G., Gieré, R. and Kartashov, P.M. (2010) The pyrochlore supergroup of minerals: nomenclature. The Canadian Mineralogist, 48, 673698.CrossRefGoogle Scholar
Bourdon, B., Henderson, G.M., Lundstrom, C.C. and Turner, S.P. (editors) (2003) Uranium-Series Geochemistry. Reviews in Mineralogy & Geochemistry, 52. Mineralogical Society of America, Washington D.C. and the Geochemical Society, St Louis, Missouri, USA, 656 pp.CrossRefGoogle Scholar
Burns, P.C. (1999) The crystal chemistry of uranium. Pp. 23—90 in: Uranium: Mineralogy, Geochemistry and the Environment (Burns, P.C. and Finch, R., editors). Reviews in Mineralogy, 38. Mineralogical Society of America, Washington D.C. CrossRefGoogle Scholar
Burns, P.C. (2005) U6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. The Canadian Mineralogist, 43, 18391894.CrossRefGoogle Scholar
Burns, P.C. and Finch, R. (editors) (1999) Uranium: Mineralogy, Geochemistry and the Environment. Reviews in Mineralogy, 38. Mineralogical Society of America, Washington D.C, 679 pp.CrossRefGoogle Scholar
Burns, P.C., Miller, M.L. and Ewing, R.C. (1996) U6+ minerals and inorganic phases: a comparison and hierarchy of structures. The Canadian Mineralogist, 34, 845880.Google Scholar
Carter, LJ. and Pigford, T.H. (1999) The world's growing inventory of civil spent fuel. Arms Control Today, 8, 814.Google Scholar
Chakoumakos, B.C. (1984) Systematics of the pyro-chlore structure type, ideal A2B2X6Y. Journal of Solid State Chemistry, 53, 120129.CrossRefGoogle Scholar
Chakoumakos, B.C. and Ewing, R.C. (1985) Crystal chemical constraints on the formation of actinide pyrochlores. Materials Research Society Symposia Proceedings, 44, 641—646.Google Scholar
Chartier, A., Meis, C., Weber, W.J. and Corrales, L.R. (2002) Theoretical study of disorder in Ti-substituted La2Zr2O7. Physical Review B, 65, http://dx.doi.org/10.1103/PhysRevB.65.134116. CrossRefGoogle Scholar
Donald, I.W., Metcalfe, B.L. and Taylor, R.NJ. (1997) The immobilization of high level radioactive wastes using ceramics and glasses. Journal of Materials Science, 32, 58515887.CrossRefGoogle Scholar
Ewing, R.C. (1975) The crystal chemistry of complex niobium and tantalum oxides. IV. The metamict state: discussion. American Mineralogist, 60, 728730.Google Scholar
Ewing, R.C. (1976) Metamict mineral alteration: an implication for radioactive waste disposal. Science, 192, 13361337.CrossRefGoogle ScholarPubMed
Ewing, R.C. (1999) Nuclear waste forms for actinides. Proceedings of the National Academy of Sciences of the United States of America, 96, 34323439.CrossRefGoogle ScholarPubMed
Ewing, R.C. (2001) The design and evaluation of nuclear-waste forms: clues from mineralogy. The Canadian Mineralogist, 39, 697—715.CrossRefGoogle Scholar
Ewing, R.C. (2004) Environmental impact of the nuclear fuel cycle. Pp. 7—35 in: Energy, Waste, and the Environment: A Geochemical Perspective (Gieré, R. and Stille, P., editors). Special Publications, 236, Geological Society, London.CrossRefGoogle Scholar
Ewing, R.C. (2005) Plutonium and “minor” actinides: safe sequestration. Earth and Planetary Science Letters, 229, 165181.CrossRefGoogle Scholar
Ewing, R.C. (2011) Safe management of actinides in the nuclear fuel cycle: role of mineralogy. Comptes Rendus Geoscience, 343, 219229.CrossRefGoogle Scholar
Ewing, R.C. and Weber, J.W. (2010) Actinide waste forms and radiation effects. Pp. 38133888 in: The Chemistry of the Actinides and Transactinide Elements, vol. 6, (Morss, L.R., Edelstein, N.M. and Fuger, J., editors). Springer, New York.CrossRefGoogle Scholar
Ewing, R.C., Weber, W.J. and Clinard, F.W., Jr. (1995) Radiation effects in nuclear waste forms for high-level radioactive waste. Progress in Nuclear Energy, 29, 63127.CrossRefGoogle Scholar
Ewing, R.C., Meldrum, A., Wang, L.M. and Wang, S.X. (2000) Radiation-induced amorphization. Pp. 317—361 in: Transformation Processes in Minerals (Redfern, S.A.T. and Carpenter, M.A., editors). Reviews in Mineralogy & Geochemistry, 39. Mineralogical Society of America, Washington D.C. and the Geochemical Society, St Louis, Missouri, USA.Google Scholar
Ewing, R.C., Meldrum, A., Wang, L.M., Weber, W.J. and Corrales, L.R. (2003) Radiation effects in zircon. Pp. 387425 in: Zircon (Hanchar, J.M. and Hoskin, P.W.O., editors) Reviews in Mineralogy & Geochemistry, 53. Mineralogical Society of America, Washington D.C. and the Geochemical Society, St Louis, Missouri, USA.CrossRefGoogle Scholar
Ewing, R.C., Weber, W.J and Lian, J. (2004a) Nuclear waste disposal — pyrochlore (A2B2O7): nuclear waste form for the immobilization of plutonium and “minor” actinides. Journal of Applied Physics, 95, 59495971.CrossRefGoogle Scholar
Ewing, R.C., Lian, J. and Wang, L.M. (2004b) Ion beam-induced amorphization of the pyrochlore structure-type: a review. Materials Research Society Symposia Proceedings, 792, 37—48.Google Scholar
Ewing, R.C., Runde, W. and Albrecht-Schmitt, T.E. (2010) Environmental impact of the nuclear fuel cycle: fate of actinides. Materials Research Society Bulletin, 35, 859866.CrossRefGoogle Scholar
Hedin, A. (1997) Spent nuclear fuel — how dangerous is it? SKB Technical Report 97-13, 60 pp.Google Scholar
Helean, K.B., Ushakov, S.V., Brown, C.E., Navrotsky, A., Lian, J., Ewing, R.C., Farmer, J.M. and Boatner, L.A. (2004) Formation enthalpies of rare earth titanate pyrochlores. Journal of Solid State Chemistry, 177, 18581866.CrossRefGoogle Scholar
Hoffman, D.C., Lawrence, F.O., Mewherter, J.L. and Rourke, F.M. (1971) Detection of plutonium-244 in nature. Nature, 234, 132134.CrossRefGoogle Scholar
Hoffmann, R. (1987) An Unusual State of Matter. Pp. 101—102 in: The Metamict State. University of Florida Press, Gainesville, Florida, USA.Google Scholar
Imaura, A., Touran, N. and Ewing, R.C. (2009) MgO-pyrochlore composite as an inert matrix fuel: neutronic and thermal characteristics. Journal of Nuclear Materials, 389, 341350.CrossRefGoogle Scholar
Janeczek, J. (1999) Mineralogy and geochemistry of natural fission reactors in Gabon. Pp. 321—392 in: Uranium: Mineralogy, Geochemistry and the Environment (Burns, P.C. and Finch, R., editors). Reviews in Mineralogy, 38. Mineralogical Society of America, Washington D.C.CrossRefGoogle Scholar
Jensen, K.A. and Ewing, R.C. (2001) The Okélobondo natural fission reactor, southeast Gabon: geology, mineralogy and retardation of nuclear reaction products. Geological Society of America Bulletin, 113, 3262.2.0.CO;2>CrossRefGoogle Scholar
Kennedy, B.J., Hunter, B.A. and Howard, C.J. (1997) Structural and bonding trends in tin pyrochlore oxides. Journal of Solid State Chemistry, 130, 5865.CrossRefGoogle Scholar
Kersting, A.B., Efürd, D.W., Finnegan, D.L., Rokop, D.J., Smith, D.K., and Thompson, J.L. (1999). Migration of plutonium in groundwater at the Nevada Test Site. Nature, 397, 5659.CrossRefGoogle Scholar
Kulkarni, N.K., Sampath, S. and Venugopal, V. (2000) Preparation and characterisation of Pu-pyrochlore: [La1–xPux]2Zr2O7 (x = 0-1). Journal of Nuclear Materials, 281, 248250.CrossRefGoogle Scholar
Laverov, N.P., Yudintsev, S.V., Stefanovsky, S.V., and Jang, Y.N. (2001) New actinide matrix with pyrochlore structure. Doklady Earth Sciences, 381, 10531055.Google Scholar
Laverov, N.P., Yudintsev, S.V., Stefanovsky, S.V., Jang, Y.N and Ewing, R.C. (2002) Synthesis and examination of new actinide pyrochlores. Materials Research Society Symposia Proceedings, 713, 337343.CrossRefGoogle Scholar
Lang, M., Lian, J., Zhang, F. Hendriks, B.W.H., Trautmann, C., Neumann, R. and Ewing, R.C. (2008) Fission tracks simulated by swift heavy ions at crustal pressures and temperatures. Earth and Planetary Science Letters, 274, 355—358.CrossRefGoogle Scholar
Lang, M., Zhang, F., Zhang, J.M., Wang, J.W., Schuster, B., Trautmann, C., Neumann, R., Becker, U. and Ewing, R.C. (2009) Nanoscale manipulation of the properties of solids at high pressure with relativistie heavy ions. Nature Materials, 8, 793—797.CrossRefGoogle ScholarPubMed
Lang, M., Zhang, F., Zhang, J.M., Wang, J.W., Lian, J., Weber, W.J., Schuster, B., Trautmann, C., Neumann, R. and Ewing, R.C. (2010) Review of A2B2O7 pyrochlore response to irradiation and pressure. Nuclear Instruments and Methods in Physics Research B., 268, 29512958.CrossRefGoogle Scholar
Lian, J., Zu, X.T., Kutty, K.V.G., Chen, J., Wang, L.M. and Ewing, R.C. (2002) Ion-irradiation-induced amorphization of La2Zr2O7 pyrochlore. Physical Review B, 66, http://dx.doi.org/10.1103/PhysRevB.66.054108. CrossRefGoogle Scholar
Lian, J., Chen, J., Wang, L.M., Ewing, R.C., Farmer, J.M., Boatner, L.A. and Helean, K.B. (2003) Radiation-induced amorphization of rare-earth tita-nate pyrochlores. Physical Review B, 68, http://dx.doi.org/10.1103/PhysRevB.68.134107.CrossRefGoogle Scholar
Lian, J., Ewing, R.C., Wang, L.M. and Helean, K.B. (2004a) Ion beam irradiation of Gd2Sn2O7 and Gd2Hf2O7 pyrochlore: bond-type effect. Journal of Materials Research, 19, 15751580.CrossRefGoogle Scholar
Lian, J., Wang, L.M., Haire, R.G., Helean, K.B. and Ewing, R.C. (20046) Ion beam irradiation effects in La2Zr2O7—Ce2Zr2O7 pyrochlore. Nuclear Instruments and Methods in Physics Research Section B, 218, 236243.CrossRefGoogle Scholar
Lumpkin, G.R. (2001) Alphα-decay damage and aqueous durability of actinide host phases in natural systems. Journal of Nuclear Materials, 289, 136166.CrossRefGoogle Scholar
Lumpkin, G.R. (2006) Ceramic waste forms for actinides. Elements, 2, 365—372.Google Scholar
Lumpkin, G.R., Chakoumakos, B.C. and Ewing, R.C. (1986) Mineralogy and radiation effects of mierolite from the Harding pegmatite, Taos County, New Mexico. American Mineralogist, 71, 569—588.Google Scholar
Lumpkin, G.R. and Ewing, R.C. (1988) Alphα-decay damage in minerals of the pyrochlore group. Physics and Chemistry of Minerals, 16, 2—20.CrossRefGoogle Scholar
Lumpkin, G.R., Smith, K.L., Gieré, R. and Williams, C.T. (2004) The geochemical behaviour of host phases for actinides and fission products in crystal-line ceramic nuclear waste forms. Pp. 89—111 in: Energy, Waste, and the Environment: A Geochemical Perspective (Gieré, R. and Stille, P., editors). Special Publications, 236, Geological Society, London.CrossRefGoogle Scholar
Lutze, W. and Ewing, R.C. (editors) (1988) Radioactive Waste Forms for the Future. North-Holland, Amsterdam, 778 pp.Google Scholar
Macfarlane, A. (1998) Immobilization of excess weapon plutonium: a better alternative to glass. Science & Global Security, 7, 271309.CrossRefGoogle Scholar
Mark, J.C. (1993) Explosive properties of reactor-grade plutonium. Science & Global Security, 4, 111—128.Google Scholar
National Research Council (1994) Management and Disposition of Excess Weapons Plutonium. The National Academy Press, Washington, D.C. 288 pp.Google Scholar
Novikov, A.P., Kalymkov, S.N. Utsunomiya, S., Ewing, R.C., Horreard, F., Merkulov, A., Clark, S.B., Tkachev, V.V. and Myasoedov, B.F. (2006) Colloid transport of plutonium in the far-field of the Mayak Production Association, Russia. Science, 314, 638641.CrossRefGoogle ScholarPubMed
Pabst, A. (1952) The metamict state. American Mineralogist, 37, 137157.Google Scholar
Panero, W.R., Stixrude, L. and Ewing, R.C. (2004) First-principle calculation of defect-formation energies in Y2(Ti,Sn,Zr)2O7 pyrochlore. Physical Review B, 70, http://dx.doi.Org/10.l103/PhysRevB.70.054110.Google Scholar
Primak, W. (1954) The metamict state. Physical Review. 95, 837.CrossRefGoogle Scholar
Purton, J.A. and Allan, NX. (2002) Displacement cascades in Gd2Ti2O7 and Gd2Zr2O7: a molecular dynamics study. Journal of Materials Chemistry, 12, 29232926.CrossRefGoogle Scholar
Raison, P.E., Haire, R.G., Sato, T. and Ogawa, T. (1999) Fundamental and technological aspects of actinide oxide pyrochlores: relevance for immobilization matrices. Materials Research Society Symposium Proceedings, 556, 3—10.CrossRefGoogle Scholar
Ringwood, A.E. (1985) Disposal of high-level nuclear wastes: a geological perspective. Mineralogical Magazine, 49, 159176.CrossRefGoogle Scholar
Runde, W. (2000) The chemical interactions of actinides in the environment. Challenges in Plutonium Science, volume II. 26, 392—411.Google Scholar
Runde, W. and Neu, M.P. (2010) Actinides in the geosphere. Pp. 3475—3593 in: The Chemistry of the Actinide and Transactinide Elements, volume 6 (Morss, L.R., Edelstein, N.M. and Fuger, J., editors). Springer, Dordrecht, The Netherlands.Google Scholar
Sickafus, K.E., Minervini, L., Grimes, R.W., Valdez, J.A., Ishimaru, M., Li, F., McClellan, KJ. and Hartmann, T. (2000) Radiation tolerance of complex oxides. Science, 289, 748751.CrossRefGoogle ScholarPubMed
Silva, RJ. and Nitsche, H. (2002) Environmental chemistry. Pp. 89—117 in: Advances in Plutonium Chemistry 1967-2000 (Hoffman, D.C., editor). American Nuclear Society, La Grange Park, Illinois, USA.Google Scholar
Subramanian, M.A., Aravamudan, G. and Rao, G.V.S. (1983) Oxide pyrochlores — a review. Progress in Solid State Chemistry, 15, 55143.CrossRefGoogle Scholar
Wang, J., Zhang, F., Lian, J., Ewing, R.C. and Becker, U. (2011) Energetics and concentration of defects in Gd2Ti2O7 and Gd2Zr2O7 pyrochlore at high pressure. Acta Materialia, 59, 16071618.CrossRefGoogle Scholar
Wang, L.M. and Ewing, R.C. (1992) Ion-beam-induced amorphization of complex ceramic materials — minerals. Materials Research Society Bulletin, 17, 3844.CrossRefGoogle Scholar
Wang, S.X., Begg, B.D., Wang, L.M., Ewing, R.C., Weber, W.J and Kutty, K.V.G. (1999a) Radiation stability of gadolinium zirconate: a waste form for plutonium disposition. Journal of Materials Research, 14, 44704473.CrossRefGoogle Scholar
Wang, S.X., Wang, L.M., Ewing, R.C., Was, G.S. and Lumpkin, G.R. (19996) Ion irradiation-induced phase transformation of pyrochlore and zirconolite. Nuclear Instruments and Methods in Physics Research Section B, 148, 704709.CrossRefGoogle Scholar
Wang, S.X., Wang, L.M. and Ewing, R.C. (2001) Irradiation-induced amorphization: effects of temp-erature, ion mass, cascade size, and dose rate. Physical Review B, 63, http://dx.doi.org/10.1103/PhysRevB.63.024105.CrossRefGoogle Scholar
Weber, W.J (2000) Models and mechanisms of irradiation-induced amorphization in ceramics. Nuclear Instruments and Methods in Physics Research Section B, 166, 98106.CrossRefGoogle Scholar
Weber, W.I, Wald, J.W. and Matzke, Hj. (1985a) Self-radiation damage in actinide host phases for nuclear waste forms. Materials Research Society Symposium Proceedings, 8, 679686.Google Scholar
Weber, W.I, Wald, J.W. and Matzke, Hj. (19856) Self-radiation damage in Gd2Ti2O7 . Materials Letters, 3, 173180.CrossRefGoogle Scholar
Weber, W.J, Wald, J.W. and Matzke, Hj. (1986) Effects of self-radiation damage in Cm-doped Gd2Ti2O7 and CaZrTi2O7 . Journal of Nuclear Materials, 138, 196209.CrossRefGoogle Scholar
Weber, W.J., Ewing, R.C., Angell, C.A., Arnold, G.W., Cormack, A.N., Delaye, J.M., Griscom, D.L., Hobbs, L.W., Navrotsky, A., Price, D.L., Stoneham, A.M. and Weinberg, M.C. (1997) Radiation effects in glasses used for immobilization of high-level waste and plutonium disposition. Journal of Materials Research, 12, 19481978.CrossRefGoogle Scholar
Weber, W.J., Ewing, R.C., Catlow, C.R.A., Diaz de la Rubia, T., Hobbs, L.W., Kinoshita, C., Matzke, Hj., Motta, A.T., Nastasi, M., Salje, E.K.H., Vance, E.R. and Zinkle, S.J. (1998) Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium. Journal of Materials Research, 13, 14341484.CrossRefGoogle Scholar
Wigeland, R.A, Bauer, T.H., Fanning, T.H. and Morris E.E. (2006) Separations and transmutation criteria to improve utilization of a geologic repository. Nuclear Technology, 154, 95106.CrossRefGoogle Scholar
Williams, R.H. and Feiveson, H.A. (1990) How to expand nuclear power without proliferation. Bulletin of the Atomic Scientists, 46, 40—45.CrossRefGoogle Scholar
Williford, R.E. and Weber, W.J (2001) Computer simulation of Pu3+ and Pu4+ substitutions in gadolinium zirconate. Journal of Nuclear Materials, 299, 140147.CrossRefGoogle Scholar
Wuensch, BJ. and Eberman, K.W. (2000) Order-disorder phenomena in A2B2O7 pyrochlore oxides. JOM Journal of the Minerals, Metals and Materials Society, 52, 1921.CrossRefGoogle Scholar
Xiao, H.Y., Zhang, F.X., Gao, F., Lang, M., Ewing, R.C. and Weber, W.J (2010) Zirconate pyrochlores under high pressure. Physical Chemistry Chemical Physics, 12, 1247212477.CrossRefGoogle ScholarPubMed
Zhang, J.M., Livshits, T.S., Lizin, A.A., Hu, Q. and Ewing, R.C. (2010) Irradiation of synthetic garnet by heavy ions and α-decay of 244Cm. Journal of Nuclear Materials, 407, 137142.CrossRefGoogle Scholar
Ziegler, J.F., Ziegler, M.D. and Biersack, J.P. (2010) SRIM — The stopping and range of ions in matter (2010). Nuclear Instruments and Methods in Physics Research Section B, 268, 18181823.CrossRefGoogle Scholar