Consolidation of commercial-size UO2 fuel pellets using spark plasma sintering and microstructure/microchemical analysis


The development of advanced fuel fabrication technologies is important for developing accident-tolerant fuels and engineering fuels for safer and more effective nuclear energy systems. In this work, commercial-size uranium dioxide (UO2) fuel pellets with a theoretical density of 95% were consolidated by spark plasma sintering (SPS) at 1600°C for 5 min. Systematic investigations suggest uniform densification and stoichiometric UO2 with an ideal fluorite structure across the commercial-size fuel pellet, but with a distributed grain structure because of non-uniform distribution of temperature during sintering. This work demonstrates a great potential of using SPS for fabricating nuclear fuels at a cost-effective manner.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Table I
Figure 3
Figure 4
Figure 5


  1. 1.

    IAEA: Current trends in nuclear fuel for power reactors. (2007) Available at: (accessed June 17, 2018).

  2. 2.

    IAEA: Accident tolerant fuel concepts for light water reactors. (2014) Available at: (accessed June 17, 2018).

  3. 3.

    R.A. Wolfe and S.F. Kaufman: Mechanical properties of oxide fuels. (1967) Available at: (accessed June 17, 2018).

    Google Scholar 

  4. 4.

    I. Amato, R.L. Colombo, and A.M.P. Balzari: Hot-pressing of uranium dioxide. J. Nucl. Mater. 20, 210 (1966).

    CAS  Article  Google Scholar 

  5. 5.

    J. Williams, E. Barnes, R. Scott, and A. Hall: Sintering of uranium oxides of composition UO2 to U3O8 in various atmospheres. J. Nucl. Mater. 1, 28 (1959).

    CAS  Article  Google Scholar 

  6. 6.

    A.J. Carrea: Sintering of uranium dioxide in an atmosphere of controlled hydrogen content. J. Nucl. Mater. 8, 275 (1963).

    CAS  Article  Google Scholar 

  7. 7.

    T.R.G. Kutty, K.N. Chandrasekharan, J.P. Panakkal, and J.K. Ghosh: Fracture-toughness and fracture surface-energy of sintered uranium-dioxide fuel pellets. J. Mater. Sci. Lett. 6, 260 (1987).

    CAS  Article  Google Scholar 

  8. 8.

    V.V. Novikov, R.B. Sivov, E.N. Mikheev, and A.V. Fedotov: Fracture toughness of vver and pwr uranium-dioxide fuel pellets with different grain size. At. Energy 118, 117 (2015).

    CAS  Article  Google Scholar 

  9. 9.

    K. Yamada, K. Kurosaki, M. Uno, and S. Yamanaka: Evaluation of thermal properties of uranium dioxide by molecular dynamics. J. Alloys Compd. 307, 10 (2000).

    CAS  Article  Google Scholar 

  10. 10.

    T. Arima, S. Yamasaki, Y. Inagaki, and K. Idemitsu: Evaluation of thermal properties of UO2 and PuO2 by equilibrium molecular dynamics simulations from 300 to 2000 K. J. Alloys Compd. 400, 43 (2005).

    CAS  Article  Google Scholar 

  11. 11.

    J.H. Harding and D.G. Martin: A recommendation for the thermal-conductivity of UO2. J. Nucl. Mater. 166, 223 (1989).

    CAS  Article  Google Scholar 

  12. 12.

    T. Watanabe, S.B. Sinnott, J.S. Tulenko, R.W. Grimes, P.K. Schelling, and S.R. Phillpot: Thermal transport properties of uranium dioxide by molecular dynamics simulations. J. Nucl. Mater. 375, 388 (2008).

    CAS  Article  Google Scholar 

  13. 13.

    S. Wei, Z.H. Zhang, X.B. Shen, F.C. Wang, M.Y. Sun, R. Yang, and S.K. Lee: Simulation of temperature and stress distributions in functionally graded materials synthesized by a spark plasma sintering process. Comput. Mater. Sci. 60, 168 (2012).

    CAS  Article  Google Scholar 

  14. 14.

    L.H. Ge, G. Subhash, R.H. Baney, J.S. Tulenko, and E. McKenna: Densification of uranium dioxide fuel pellets prepared by spark plasma sintering (SPS). J. Nucl. Mater. 435, 1 (2013).

    CAS  Article  Google Scholar 

  15. 15.

    V. Tyrpekl, M. Naji, M. Holzhauser, D. Freis, D. Prieur, P. Martin, B. Cremer, M. Murray-Farthing, and M. Cologna: On the role of the electrical field in spark plasma sintering of UO2+x. Sci. Rep. 7, 46625 (2017).

    CAS  Article  Google Scholar 

  16. 16.

    T.K. Yao, S.M. Scott, G.Q. Xin, B.W. Gong, and J. Lian: Dense nanocrystalline UO2+x fuel pellets synthesized by high pressure spark plasma sintering. J. Am. Ceram. Soc. 101, 1105 (2018).

    CAS  Article  Google Scholar 

  17. 17.

    T.K. Yao, K. Mo, D. Yun, S. Nanda, A.M. Yacout, and J. Lian: Grain growth and pore coarsening in dense nano-crystalline UO2+x fuel pellets. J. Am. Ceram. Soc. 100, 2651 (2017).

    CAS  Article  Google Scholar 

  18. 18.

    M. Sopicka-lizer: Introduction to mechanochemical processing. (Woodhead Publishing, Cambridge, England, 2010), p. 1.

    Google Scholar 

  19. 19.

    A. Wank and B. Wielage: High energy ball milling–a promising route for production of tailored thermal spray consumables. (Conference on Modern wear and corrosion resistant coatings obtained by thermal spraying, Warsaw, Poland, 2003).

    Google Scholar 

  20. 20.

    K. Teske, H. Ullmann, and D. Rettig: Investigation of the oxygen activity of oxide fuels and fuel-fission product systems by solid electrolyte techniques. Part I: qualification and limitations of the method. J. Nucl. Mater. 116, 260 (1983).

    CAS  Article  Google Scholar 

  21. 21.

    L.H. Ge, G. Subhash, R.H. Baney, and J.S. Tulenko: Influence of processing parameters on thermal conductivity of uranium dioxide pellets prepared by spark plasma sintering. J. Eur. Ceram. Soc. 34, 1791 (2014).

    CAS  Article  Google Scholar 

  22. 22.

    S. Gossé, C. Guéneau, T. Alpettaz, S. Chatain, C. Chatillon, and F. Le Guyadec: Kinetic study of the UO2/C interaction by high-temperature mass spectrometry. Nucl. Eng. Des. 238, 2866 (2008).

    Article  CAS  Google Scholar 

  23. 23.

    S. Gossé, C. Guéneau, C. Chatillon, and S. Chatain: Critical review of carbon monoxide pressure measurements in the uranium–carbon–oxygen ternary system. J. Nucl. Mater. 352, 13 (2006).

    Article  CAS  Google Scholar 

  24. 24.

    J.E. Burke and D. Turnbull: Recrystallization and grain growth. Prog. Met. Phys. 3, 220 (1952).

    CAS  Article  Google Scholar 

  25. 25.

    W.D. Kingery and B. Francois: Grain growth in porous compacts. J. Am. Ceram. Soc. 48, 546 (1965).

    CAS  Article  Google Scholar 

  26. 26.

    F.A. Nichols: Theory of grain growth in porous compacts. J. Appl. Phys. 37, 4599 (1966).

    CAS  Article  Google Scholar 

  27. 27.

    J. Diatta, G. Antou, N. Pradeilles, and A. Maître: Numerical modeling of spark plasma sintering—discussion on densification mechanism identification and generated porosity gradients. J. Eur. Ceram. Soc. 37, 4849 (2017).

    CAS  Article  Google Scholar 

  28. 28.

    P. Mondalek, L. Silva, and M. Bellet: A numerical model for powder densification by sps technique. Adv. Eng. Mater. 13, 587 (2011).

    CAS  Article  Google Scholar 

  29. 29.

    C. Wang, Z. Zhao, and L.F. Cheng: Finite element modeling of temperature distribution in spark plasma sintering. Key Eng. Mater. 434–435, 808 (2010).

    Article  CAS  Google Scholar 

  30. 30.

    P.R. Graves: Raman microprobe spectroscopy of uranium-dioxide single-crystals and ion-implanted polycrystals. Appl. Spectrosc. 44, 1665 (1990).

    CAS  Article  Google Scholar 

  31. 31.

    W.B. White: Application of infrared spectroscopy to order-disorder problems in simple ionic solids. Mater. Res. Bull. 2, 381 (1967).

    CAS  Article  Google Scholar 

  32. 32.

    M. Razdan and D.W. Shoesmith: Influence of trivalent-dopants on the structural and electrochemical properties of uranium dioxide (UO2). J. Electrochem. Soc. 161, H105 (2014).

    CAS  Article  Google Scholar 

  33. 33.

    M. Razdan and D.W. Shoesmith: The electrochemical reactivity of 6.0 wt% gd-doped UO2 in aqueous carbonate/bicarbonate solutions. J. Electrochem. Soc. 161, H225 (2014).

    CAS  Article  Google Scholar 

  34. 34.

    G.C. Allen, I.S. Butler, and N.A. Tuan: Characterization of uranium-oxides by micro-Raman spectroscopy. J. Nucl. Mater. 144, 17 (1987).

    CAS  Article  Google Scholar 

  35. 35.

    M.L. Palacios and S.H. Taylor: Characterization of uranium oxides using in situ micro-Raman spectroscopy. Appl. Spectrosc. 54, 1372 (2000).

    CAS  Article  Google Scholar 

  36. 36.

    D. Manara and B. Renker: Raman spectra of stoichiometric and hyperstoichiometric uranium dioxide. J. Nucl. Mater. 321, 233 (2003).

    CAS  Article  Google Scholar 

  37. 37.

    M. Naji, J.Y. Colle, O. Benes, M. Sierig, J. Rautio, P. Lajarge, and D. Manara: An original approach for Raman spectroscopy analysis of radioactive materials and its application to americium-containing samples. J. Raman Spectrosc. 46, 750 (2015).

    CAS  Article  Google Scholar 

  38. 38.

    M. Chollet, D. Prieur, R. Bohler, R. Belin, and D. Manara: The melting behaviour of uranium/neptunium mixed oxides. J. Chem. Thermodyn. 89, 27 (2015).

    CAS  Article  Google Scholar 

  39. 39.

    T. Livneh and E. Sterer: Effect of pressure on the resonant multiphonon Raman scattering in UO2. Phys. Rev. B 73, 085118 (2006).

    Article  CAS  Google Scholar 

  40. 40.

    L. Desgranges, G. Guimbretiere, P. Simon, C. Jegou, and R. Caraballo: A possible new mechanism for defect formation in irradiated UO2. Nucl. Instrum. Methods. B 315, 169 (2013).

    CAS  Article  Google Scholar 

  41. 41.

    L. Desgranges, G. Baldinozzi, P. Simon, G. Guimbretière, and A. Canizares: Raman spectrum of U4O9: a new interpretation of damage lines in UO2. J. Raman Spectrosc. 43, 455 (2012).

    CAS  Article  Google Scholar 

  42. 42.

    M.a.S. Razdan and David W: The electrochemical reactivity of 6.0 wt% Gd-doped UO2 in aqueous carbonate/bicarbonate solutions. J. Electrochem. Soc. 161, H225 (2014).

    CAS  Article  Google Scholar 

  43. 43.

    H. He and D. Shoesmith: Raman spectroscopic studies of defect structures and phase transition in hyper-stoichiometric UO(2+x). Phys. Chem. Chem. Phys. 12, 8108 (2010).

    CAS  Article  Google Scholar 

  44. 44.

    D. Ho Mer Lin, D. Manara, P. Lindqvist-Reis, T. Fanghänel, and K. Mayer: The use of different dispersive Raman spectrometers for the analysis of uranium compounds. Vib. Spectrosc. 73, 102 (2014).

    CAS  Article  Google Scholar 

  45. 45.

    F. Pointurier and O. Marie: Identification of the chemical forms of uranium compounds in micrometer-size particles by means of micro-Raman spectrometry and scanning electron microscope. Spectrochim. Acta Part B 65, 797 (2010).

    Article  CAS  Google Scholar 

  46. 46.

    J. Schoenes: Recent spectroscopic studies of UO2. J. Chem. Soc. Faraday Trans. 283, 1205 (1987).

    Article  Google Scholar 

Download references


This work is supported by the US Department of Energy, Office of Nuclear Energy under a Nuclear Engineer University Program (award number: DE-NE0008440) and an internal support by Westinghouse Electric Company in developing advanced technology for fuel fabrication.

Author information



Corresponding author

Correspondence to Jie Lian.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Gong, B., Yao, T., Lu, C. et al. Consolidation of commercial-size UO2 fuel pellets using spark plasma sintering and microstructure/microchemical analysis. MRS Communications 8, 979–987 (2018).

Download citation