Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지
DOI QR코드

DOI QR Code

Order-disorder structural tailoring and its effects on the chemical stability of (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic for nuclear waste forms

  • Wang, Yan (Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology) ;
  • Wang, Jin (Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology) ;
  • Zhang, Xue (School of Materials Science and Engineering, Southwest University of Science and Technology) ;
  • Li, Nan (School of Materials Science and Engineering, Southwest University of Science and Technology) ;
  • Wang, Junxia (School of Materials Science and Engineering, Southwest University of Science and Technology) ;
  • Liang, Xiaofeng (Sichuan College of Traditional Chinese Medicine)
  • Received : 2021.11.29
  • Accepted : 2022.02.01
  • Published : 2022.07.25
Download PDF
⟨ Previous Next ⟩

Abstract

Series of unequal quantity Nd/Ce co-doped ceramic nuclear waste forms, (Gd, Nd)2(Zr, Ce)2O7, were prepared to tailor its ordered pyrochlore or disordered fluorite structure. The phase transition, microtopography, and elemental composition of the ceramic samples were systematically investigated, especially the effect of order-disorder structure on the chemical stability. It was confirmed that unequal quantity of Nd/Ce could synchronously replace the Gd/Zr-sites of Gd2Zr2O7. And the phase transition of order-disorder structure could be successfully tailored by regulating the average cationic radius ratio of (Gd, Nd)2(Zr, Ce)2O7 series. The elements of Gd, Nd, Zr, and Ce are uniformly distributed in the ordered or disordered structures. The MCC-1 leaching results showed that (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic nuclear waste forms had excellent chemical stability, whose elements' normalized leaching rates were as low as 10-4-10-7 g·m-2·d-1 after 7 days. In particular, the chemical stability of disordered structure was superior to that of ordered structure. It was proposed that the force constant and the closest packing were changed with the structure transformation resulting the chemical stability difference.

Keywords

Acknowledgement

We received a great deal of support and assistance from the National Natural Science Foundation of China (Nos. 12075195 and 11705153), the Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety of Southwest University of Science and Technology (No. 17kfhk05).

References

  1. E. Sartori, Nuclear data for radioactive waste management, Ann. Nucl. Energy 62 (2013) 579-589. https://doi.org/10.1016/j.anucene.2013.02.003
  2. M.M. Abu-Khader, Recent advances in nuclear power: a review, Prog. Nucl. Energy 51 (2009) 225-235. https://doi.org/10.1016/j.pnucene.2008.05.001
  3. A.E. Ringwood, S.E. Kesson, N.G. Ware, W.O. Hibberson, Immobilisation of high level nuclear reactor wastes in SYNROC, Nature 278 (1979) 219-223. https://doi.org/10.1038/278219a0
  4. E.R. Vance, G.R. Lumpkin, M.L. Carter, D.J. Cassidy, C.J. Ball, R.A. Day, B.D. Begg, Incorporation of uranium in zirconolite (CaZrTi2O7), J. Am. Ceram. Soc. 85 (2002) 1853-1859. https://doi.org/10.1111/j.1151-2916.2002.tb00364.x
  5. R.C. Ewing, W.J. Weber, J. Lian, Nuclear waste disposal-pyrochlore (A2B2O7): nuclear waste form for the immobilization of plutonium and "minor" actinides, J. Appl. Phys. 95 (2004) 5949-5971. https://doi.org/10.1063/1.1707213
  6. N.U. Navi, S.V. Ushakov, R.Z. Shneck, M.H. Mintz, Yttrium substitution in MTiO3 (M=Ca, Sr, Ba and Ca+Sr+Ba) perovskites and implication for incorporation of fission products into ceramic waste forms, J. Am. Ceram. Soc. 94 (2011) 3112-3116. https://doi.org/10.1111/j.1551-2916.2011.04474.x
  7. G.J. Mccarthy, W.B. White, D.E. Pfoertsch, Synthesis of nuclear waste monazites, ideal actinide hosts for geologic disposal, M.R.S. Bull. 13 (1978) 1239-1245. https://doi.org/10.1016/0025-5408(78)90215-5
  8. R.C. Ewing, Nuclear waste forms for actinides, Proc. Natl. Acad. Sci. Unit. States Am. 96 (1999) 3432-3439. https://doi.org/10.1073/pnas.96.7.3432
  9. W.J. Weber, A. Navrotsky, S. Stefanovsky, E.R. Vance, E. Vernaz, Materials science of high-level nuclear waste immobilization, M.R.S. Bull. 34 (2009) 46-53. https://doi.org/10.1557/mrs2009.12
  10. M. Jafar, S.B. Phapale, B.P. Mandal, R. Mishra, A.K. Tyagi, Preparation and structure of Uranium-incorporated Gd2Zr2O7 compounds and their thermodynamic stabilities under oxidizing and reducing conditions, Inorga. Chem. 54 (2015) 9447-9457. https://doi.org/10.1021/acs.inorgchem.5b01300
  11. M. Lang, F. Zhang, J. Zhang, J. Wang, J. Lian, W.J. Weber, B. Schuster, C. Trautmann, R. Neumann, R.C. Ewing, Review of A2B2O7 pyrochlore response to irradiation and pressure, Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms 268 (2010) 2951-2959. https://doi.org/10.1016/j.nimb.2010.05.016
  12. K.E. Sickafus, L. Minervini, R.W. Grimes, J.A. Valdez, M. Ishimaru, F. Li, K.J. Mcclellan, T. Hartmann, Radiation tolerance of complex oxides, Science 289 (2000) 748-751. https://doi.org/10.1126/science.289.5480.748
  13. S.X. Wang, L.M. Wang, R.C. Ewing, G.S. Was, G.R. Lumpkin, Ion irradiation-induced phase transformation of pyrochlore and zirconolite, Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms 148 (1999) 704-709. https://doi.org/10.1016/S0168-583X(98)00847-7
  14. F.W. Poulsen, M. Glerup, P. Holtappels, Structure, Raman spectra and defect chemistry modelling of conductive pyrochlore oxides, Solid State Ionics 135 (2000) 595-602. https://doi.org/10.1016/S0167-2738(00)00417-3
  15. A. Garbout, S. Bouattour, A.W. Kolsi, Solegel synthesis, structure characterization and Raman spectroscopy of Gd2-2xBi2xTi2O7 solid solutions, J. Alloys Compd. 469 (2009) 229-236. https://doi.org/10.1016/j.jallcom.2008.01.086
  16. R.C. Ewing, W.J. Weber, F.W. Clinard, Radiation effects in nuclear waste forms for high-level radioactive waste, Prog. Nucl. Energy 29 (1995) 63-127. https://doi.org/10.1016/0149-1970(94)00016-Y
  17. W.J. Weber, R.C. Ewing, Plutonium immobilization and radiation effects, Science 289 (2000) 2051. https://doi.org/10.1126/science.289.5487.2051
  18. X. Wang, K. Jiang, L. Zhou, Characterization, and phase stability of pyrochlore (Nd1-xCex)2Zr2O7+y (x = 0-1), J. Nucl. Mater. 458 (2015) 156-161. https://doi.org/10.1016/j.jnucmat.2014.12.075
  19. J. Lian, K.B. Helean, B.J. Kennedy, L.M. Wang, A. Navrotsky, R.C. Ewing, Effect of structure and thermodynamic stability on the response of lanthanide stannate pyrochlores to ion beam irradiation, J. Phys. Chem. B 110 (2006) 2343-2350. https://doi.org/10.1021/jp055266c
  20. B.J. Wuensch, K.W. Eberman, C. Heremans, E.M. Ku, P. Onnerud, E.M.E. Yeo, S.M. Haile, J.K. Stalick, J.D. Jorgensen, Connection between oxygen-ion conductivity of pyrochlore fuel-cell materials and structural change with composition and temperature, Solid State Ionics 129 (2016) 111-133. https://doi.org/10.1016/S0167-2738(99)00320-3
  21. Y.H. Zhang, M. Xie, F. Zhou, H. Zhang, X.K. Zhao, Phase structure and thermophysical properties of co-doped La2Zr2O7 ceramics for thermal barrier coatings, Ceram. Int. 38 (2012) 3607-3612. https://doi.org/10.1016/j.ceramint.2011.12.077
  22. B.P. Mandal, A.K. Tyagi, Preparation and high temperature-XRD studies on a pyrochlore series with the general composition Gd2-xNdxZr2O7, J. Alloys Compd. 437 (2007) 260-263. https://doi.org/10.1016/j.jallcom.2006.07.093
  23. S.J. Patwe, B.R. Ambekar, A.K. Tyagi, Synthesis, characterization and lattice thermal expansion of some compounds in the system Gd2CexZr2-xO7, J. Alloys Compd. 389 (2005) 243-246. https://doi.org/10.1016/j.jallcom.2004.06.094
  24. J. Wang, J. Wang, Y. Zhang, Y. Li, Y. Teng, Z. Wang, H. Tan, Flux synthesis and chemical stability of Nd and Ce co-doped (Gd1-xNdx)2(Zr1-xCex)2O7 (0 ≤ x ≤ 1) pyrochlore ceramics for nuclear waste forms, Ceram. Int. 43 (2017) 17064-17070. https://doi.org/10.1016/j.ceramint.2017.09.121
  25. J. Wang, J. Wang, Y. Zhang, Y. Wei, K. Zhang, H. Tan, X. Liang, Order-disorder phase structure, microstructure, and aqueous durability of (Gd, Sm)2(Zr, Ce)2O7 ceramics for immobilizing actinides, Ceram. Int. 45 (2019) 17898-17904. https://doi.org/10.1016/j.ceramint.2019.06.006
  26. M. Jafar, S.B. Phapale, S. Nigam, S.N. Achary, A.K. Tyagi, Implication of aliovalent cation substitution on structural and thermodynamic stability of Gd2Ti2O7: Experimental and theoretical investigations, J. Alloys Compd. 859 (2020) 157781.
  27. ASTM C1220-98, Standard Test Method for Static Leaching of Monolithic Waste Forms for Disposal of Radioactive Waste, 1998. West Conshohocken, PA, USA.
  28. M. Jafar, S.B. Phapale, B.P. Mandal, M. Roy, A.K. Tyagi, Effect of temperature on phase evolution in Gd2Zr2O7: a potential matrix for nuclear waste immobilization, J. Alloys Compd. 867 (2021) 159032. https://doi.org/10.1016/j.jallcom.2021.159032
  29. B.P. Mandal, N. Garg, S.M. Sharma, A.K. Tyagi, Solubility of ThO2 in Gd2Zr2O7 pyrochlore: XRD, SEM and Raman spectroscopic studies, J. Nucl. Mater. 392 (2009) 95-99. https://doi.org/10.1016/j.jnucmat.2009.03.050
  30. A.A. Yastrebtsev, V.V. Popov, A.P. Menushenkov, A.I. Beskrovnyi, D. Neov, Kirill Ponkratov, I.V. Shchetinin, Comparative neutron and X-ray diffraction analysis of anionic and cationic ordering in rare-earth zirconates (Ln=La, Nd, Tb, Yb, Y), J. Alloy. Comp 832 (2020) 154863. https://doi.org/10.1016/j.jallcom.2020.154863
  31. B.P. Mandal, A. Banerji, V. Sathe, S.K. Deb, A.K. Tyagi, Order-disorder transition in Nd2-yGdyZr2O7 pyrochlore solid solution: an X-ray diffraction and Raman spectroscopic study, J. Solid State Chem. 180 (2007) 2643-2648. https://doi.org/10.1016/j.jssc.2007.07.007
  32. X. Shu, L. Fan, X. Lu, Y. Xie, Y. Ding, Structure and performance evolution of the system (Gd1-xNdx)2(Zr1-yCey)2O7 (0≤x, y≤1.0), J. Eur. Ceram. Soc. 35 (2015) 3095-3102. https://doi.org/10.1016/j.jeurceramsoc.2015.04.037
  33. L. Kong, I. Karatchevtseva, D.J. Gregg, M.G. Blackford, R. Holmes, G. Triani, Gd2Zr2O7 and Nd2Zr2O7 pyrochlore prepared by aqueous chemical synthesis, J. Eur. Ceram. Soc. 33 (2013) 3273-3285. https://doi.org/10.1016/j.jeurceramsoc.2013.05.011
  34. C. Nandi, A.K. Poswal, M. Jafar, S. Kesari, P.G. Behere, Effect of Ce4+-substitution at A and B sites of Nd2Zr2O7: a study for plutonium incorporation in pyrochlores, J. Nucl. Mater. 539 (2020) 152342. https://doi.org/10.1016/j.jnucmat.2020.152342
  35. K.L. Smith, G.R. Lumpkin, M.G. Blackford, R.A. Day, K.P. Hart, The durability of synroc, J. Nucl. Mater. 190 (1992) 287-294. https://doi.org/10.1016/0022-3115(92)90092-Y
  36. Y. Zhang, M.W.A. Stewart, H. Li, M.L. Carter, E.R. Vance, S. Moricca, Zirconolite-rich titanate ceramics for immobilization of actinides-waste form/H.I.P. can interactions and chemical durability, J. Nucl. Mater. 395 (2009) 69-74. https://doi.org/10.1016/j.jnucmat.2009.09.019
  37. C. Poinssot, S. Gin, Long-term Behavior Science: the cornerstone approach for reliably assessing the long-term performance of nuclear waste, J. Nucl. Mater. 420 (2012) 182-192. https://doi.org/10.1016/j.jnucmat.2011.09.012
  38. D. Horlait, L. Claparede, F. Tocino, N. Clavier, J. Ravaux, S. Szenknect, R. Podor, N. Dacheux, Environmental SEM monitoring of Ce1-xLnxO2-x/2 mixed-oxide microstructural evolution during dissolution, J. Mater. Chem. A. 2 (2014) 5193-5203. https://doi.org/10.1039/C3TA14623E
  39. X. Lu, L. Fan, X. Shu, S. Su, D. Yi, F. Yi, Phase evolution and chemical durability of co-doped Gd2Zr2O7 ceramics for nuclear waste forms, Ceram. Int. 41 (2015) 6344-6349. https://doi.org/10.1016/j.ceramint.2015.01.068
  40. D. Caurant, O. Majerus, P. Loiseau, I. Bardez, N. Baffier, J.L. Dussossoy, Long-term Behavior Science: the cornerstone approach for reliably assessing the long-term performance of nuclear waste, J. Nucl. Mater. 354 (2006) 143-162. https://doi.org/10.1016/j.jnucmat.2006.03.014
  41. S. Gin, P. Jollivet, M. Fournier, F. Angeli, P. Frugier, T. Charpentier, Origin and consequences of silicate glass passivation by surface layers, Nat. Commun. 6 (2015) 6360. https://doi.org/10.1038/ncomms7360
  42. K. Liu, K. Zhang, T. Deng, W. Li, B. Luo, H. Zhang, Preparation of Gd2Zr2O7 nanoceramics from two-step thermal treatment and the aqueous durability analysis, Ceram. Int. 46 (2020) 13040-13046. https://doi.org/10.1016/j.ceramint.2020.02.074
  43. M.T. Vandenborre, E. Husson, J.P. Chatry, D. Michel, Rare-earth titanates and stannates of pyrochlore structure: vibrational spectra and force fields, J. Raman Spectrosc. 14 (1983) 63-71. https://doi.org/10.1002/jrs.1250140202
  44. D.J. Gregg, Y. Zhang, Z. Zhang, I. Karatchevtseva, G. Triani, M.G. Blackford, G. Triani, G.R. Lumpkin, E.R. Vance, Crystal chemistry and structures of uranium-doped gadolinium zirconates, J. Nucl. Mater. 438 (2013) 144-153. https://doi.org/10.1016/j.jnucmat.2013.03.007
  45. Y.H. Lee, H.S. Sheu, J.P. Deng, H.-C.I. Kao, Preparation and fluorite-pyrochlore phase transformation in Gd2Zr2O7, J. Alloys Compd. 487 (2009) 595-598. https://doi.org/10.1016/j.jallcom.2009.08.021