Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지

Effect of pH, Redox Potential (Eh) and Carbonate Concentration on Actinides Solubility in a Deep Groundwater of Korea

  • Published : 2004.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

KAERI (Korea Atomic Energy Research Institute) is at present preparing a preliminary performance assessment to set up the HLW disposal concept of Korea. The solubility of the radionuclides contained in HLW is necessary as a source term in order to predict their potential migration in both the near and far fields. The solubility of actinides (Th, Am, U, Np and Pu) for a reference deep groundwater of Korea has been calculated using a geochemical code with thermodynamic data selected by a peer review of existing thermodynamic databases and literature. The solubilities from the experimental study and/or field observations from natural analogue studies are compared. The sensitivity of solubility to the variability of three main parameters of groundwater (pH, Eh, and carbonate concentration) is also investigated. The results of the sensitivity analysis show that the solubility of actinides strongly depends on the parameters considered. Within the range of parameter values studied (pH=7 to 10, Eh=-0.4 to -0.1V, and carbonate concentration=1.E-5 to 1.E-2 mol/L), the solubility of each actinide exists between 1.4E-10 and 1.6E-6 mol/L for Am, 4.9E-9 and 2.8E-6 mol/L for Th, 3.2E-9 and 5.7E-4 mol/L for U, 1.1E-9 and 1.0E-7 mol/L for Np, and 4.0E-11 and 2.8E-6 mol/L for Pu, respectively.

Keywords

References

  1. Keum, D.K., M.H. Baik and P.S. Hahn, Speciation and solubility of Am, U, Np and Pu in Korean deep groundwater conditions, Korean J. of Nuclide Society, Vol.34, No.2, p517-531, (2002)
  2. Keum, D.K. and P.S Hahn, Application and Development of a Multi-geochemical Reaction Equilibrium Model (MUGREM), Environment Eng. Res. Vol.4, p113-126, (1999)
  3. Keum, D.K., M.H. Baik and P.S. Hahn, Thermodynamic data of Am, Th, U, Np and Pu and their application for HLW disposal, Technical report, KAERI/TR-2046/02, (2002)
  4. Grenthe, I. et aI., Chemical Thermodynamics Series 1: Chemical Thermodynamics of uranium: NEA-TDB, GECD, North Holland Elsevier Science Publishers, (1992)
  5. Silva, R.J. et aI., Chemical Thermodynamics Series 2: Chemical Thermodynamics of Americium: NEA-TDB, OECD, North-Holland Elsevier Science Publishers, (1995)
  6. Lemire, R.J. et aI., Chemical Thermodynamics Series 4: Chemical Thermodynamics of Neptunium and Plutonium: NEA-TDB, OECD, North-Holland Elsevier Science Publishers, (2001)
  7. Bruno, J., E. Cera, J.de Pablo, L. Duro, S. Jordana, and D. Savage, Determination of radionuclide solubility limits to be used in SR 97' performance assessment exercise, Radiochim. Acta, Vol. 88, p823-828, (2000) https://doi.org/10.1524/ract.2000.88.9-11.823
  8. Grambow, B., A. Loida, A. Martinez-Esparza, P. Diaz-Arocas, J. de Pablo, J.L. Paul, G. Marx, J.P. Glatz, K. Lemmens, K. Ollila, and H. Christensen, Long-term Safety of Radioactive Waste Disposal: Source Term for Performance Assessment of Spent Fuel as a Waste Form, Final Report, Forschungszentrum Karlsruhe, FZKA 6420, (2000)
  9. Tait, J.C., S. Stroes-Gascoyne, W.H. Hocking, A.M. Duclos, R.J. Porth, and D.L. Wilkin, Dissolution behavior of used CANDU fuel under disposal conditions, Scientific Basis for Nuclear Waste Management XIV, Vol. 212, p189, (1991)
  10. Stroes-Gascoyne, S., Trends in the short-term release of fission products and actinides to aqueous solution from used CANDU fuels at elevated temperatures, J. of Nuclear materials, Vol. 190, p87, (1992) https://doi.org/10.1016/0022-3115(92)90079-Z
  11. Wilson, C.N. and H.F. Shaw, Experimental study of the dissolution of spent fuel at 850C in natural groundwater. Mat. Res. Soc., Symp. Proceedings, MRS 84, p123, (1987)
  12. Gray, W.J., Comparison of uranium release from spent fuel and un irradiated $UO_2$ in salt brine, Scientific Basis for Nuclear Waste management X, Vol. 84, p141, (1987)
  13. Wilson, C.N., Results from NNWSI series 2 bare fuel dissolution tests. Pacific Northwest Laboratory, Report PNL-7169 and PNL-7170, UC-802, (1999)
  14. Forsyth, R.S. and L.O. Werme, Spent fuel corrosion and dissolution, J. Nuclear Material, Vol. 190, p3, (1992) https://doi.org/10.1016/0022-3115(92)90071-R
  15. Neck, V. and J.I. Kim, Solubility and hydrolysis of tetravalent actinides, Radiochim. Acta, Vol. 89, p1-16, (2001) https://doi.org/10.1524/ract.2001.89.1.001
  16. Cramer, J., P. Vilks, H. Miller, and D. Bachinski, Hydrogeochemistry: Water sampling and analysis, in Final Report of SKB/AECL Cigar Lake Analog Study, AECL Technical Report, 10852, (1994)
  17. Bruno, J., C. Ayora, I. Casas, J. Delgado, L. Duro, M.J. Gimeno, J.E. Goldberg, and C.M. Linklater, EI Berrocal Project. Blind Predictive Modeling exercise, Geochemistry Task Group Report, TGR-6
  18. Bruno, J., J.E. Cross, J. Eikenberg, I.G. McKingley, D. Read, A. Sandino, and P. Sellin, Testing models of trace element geochemistry at Pocos de Cadas, J. Geochem. Exploration, Vol.45, p451-470, (1992) https://doi.org/10.1016/0375-6742(92)90135-U