Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
권호 표지

The Characteristics of an Oxidative Dissolution of Simulated Fission Product Oxides in $(NH_4)_2CO_3$ Solution Containing $H_2O_2$

$H_2O_2$ 함유 $(NH_4)_2CO_3$ 용액에서 모의 FP-산화물의 산화용해 특성

  • Published : 2009.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

This study has been carried out to look into the characteristics of an oxidative-dissolution of fission products (FP) co-dissolved with uranium (U) in a $(NH_4)_2CO_3$ carbonate solution. Simulated FP-oxides which contained 12 components have been added to the solution to examine their dissolution characteristics. It is found that $H_2O_2$ is an effective oxidant to minimize the oxidative-dissolution of FP. In the 0.5 M $(NH_4)_2CO_3$-0.5 M $H_2O_2$ solution, some elements such as Re, Te, Cs and Mo seem to be dissolved together with U, while 98${\pm}$2% for Re and Te, 94${\pm}$2% for Cs, and 29${\pm}$2 % for Mo are dissolved for 2 hours. It is revealed that dissolution rates of Re, Te and Cs are high (completely dissolved within 10${\sim}$20 minutes) due to their high solubility in the $(NH_4)_2CO_3$ solution regardless of the addition of $H_2O_2$, and independent of the concentrations of $Na_2CO_3$ and $H_2O_2$. However, the dissolution ratio of Mo seems to be slightly increased with time and about 33 % for 4 hours, indicating a very slow dissolution rate and also independent of the $(NH_4)_2CO_3$ concentration. It is found that the most important factor for the oxidative-dissolution of FP is the pH of the solution and an effective dissolution is achieved at a pH between 9${\sim}$10 in order to minimize the dissolution of FP.

본 연구는 12 성분의 모의 FP-산화물 (simulated fission products oxide)을 대상으로 하여 $(NH_4)_2CO_3-H_2O_2$ 탄산염 용액에서 U을 산화 용해할 때 U과 함께 용해되는 FP의 산화 용해특성을 규명하였다. FP-산화물의 산화용해 시 FP의 최소 용해를 위한 산화제로는 $H_2O_2$가 가장 우수하였다. 0.5 M $(NH_4)_2CO_3-0.5$ M $H_2O_2$ 계에서 U과 함께 산화 용해되는 원소로는 Re, Te, Cs, Mo 등이고, 2시간 용해에서 Re과 Te은 각각 98${\pm}$2%, Cs은 94${\pm}$2%, Mo는 29${\pm}$2%가 용해되었다. Re, Te 및 Cs의 용해는 각각 $(NH_4)_2CO_3$ 용액에서의 높은 용해도에 기인하여 $H_2O_2$ 함유 여부에 관계없이 매우 빠르게 일어나고, $(NH_4)_2CO_3$ 농도 및 $H_2O_2$의 농도증가에 거의 영향을 받지 않았다. 반면에 $H_2O_2$에 의한 Mo의 산화 용해는 $(NH_4)_2CO_3$ 농도에 무관하게 매우 느리게 일어나고, 4시간 용해에서 약 33%가 용해되었다. 그리고 용액 내 pH는 FP-산화물의 용해에 가장 큰 영향을 미치는 요인으로 U의 산화 용해 시 FP의 공용해를 방지하기 위해서 pH 9${\sim}$10에서 수행하는 것이 효과적이었다.

Keywords

References

  1. Y. S. Hwang, Y. O. Kim and J. H. Whang, "Canadian public and stakeholder engagement approach to a spent nuclear fuel management", J. Korean Radioactve Waste Soc, 6(3), pp. 179-187 (2008).
  2. Report to Congress, "DOE spent nuclear fuel recycling program plan", US Department of Energy, USA (2006).
  3. K. W. Kim, J. K. Lim, D. Y. Chung, H. B. Yang, K. C. Song, K. Y. Jee and E. H. Lee, "A process for the recovery of uranium from spent nuclear fuel by using a high alkaline carbonate solution", Korea Patent Application No. 38599 (2008).
  4. K. W. Kim, D. Y. Chung, H. B. Yang, J. K. Lim, E. H. Lee, K. C. Song and K. S. Song, "A conceptual process study for recovery of uranium alone from spent nuclear fuel by using high alkaline carbonate media", Nucl. Tech. 166, pp. 170-179 (2009). https://doi.org/10.13182/NT09-A7403
  5. Y. Asano, N. Asanuma, T. Ito, M. Kataoka, S. Fujino, T. Yamamura, W. Sugiyama, and H. Tomiyasu, "Study on a nuclear fuel reprocessing system based on the precipitation method in mild aqueous solutions", Nucl. Technol., 120, pp. 198-210 (1997). https://doi.org/10.13182/NT97-A35411
  6. N. Asanuma, M. Harada, Y. Ikeda, and H. Tomiyasu, "New approach to nuclear fuel reprocessing in non-acidic aqueous solutions", J. Nucl. Sci. Technol. 38(10), pp. 866-871 (2001). https://doi.org/10.3327/jnst.38.866
  7. D. L. Clark, D. E. Hobart, and Mary P. Neu, "Actinide carbonate complexes and their importance in actinide environmental chemistry", Chem. Rev., 95, pp. 25-48 (1995). https://doi.org/10.1021/cr00033a002
  8. S. Rollin , K. Spahiu, and U. B. Eklund, "Determination of dissolution rates of spent fuel in carbonate solutions under different redox conditions with a flow-through experiment", J. Nucl. Mater., 297, pp. 231-243 (2001). https://doi.org/10.1016/S0022-3115(01)00645-6
  9. J. Gimenez, E. Baraj, M.E. Torrero, I. Casas, and J. de Pablo, "Effect of $H_{2}O_{2}$, NaClO and Fe on the dissolution of unirradiated $UO_2$ in NaCl 5 mol/kg, Comparison with spent fuel dissolution experiments", J. Nucl. Mater., 238, pp. 64-69 (1996). https://doi.org/10.1016/S0022-3115(96)00341-8
  10. D. Dong and G. F. Vandegrift, "Kinetics of dissolution of uranium metal foil by alkaline hydrogen peroxide", Nucl. Sci. Eng., 124, pp. 473-481 (1996). https://doi.org/10.13182/NSE96-A17925
  11. F. Clarens, J. de Pablo, I. Casa, J. Gimenez, M. Rovira, J. Merino, E. Cera, J. Bruno, J. Quinones, and A. M. Esparza, "The oxidative dissolution of unirradiated $UO_2$ by hydrogen peroxide as a function of pH", J. Nucl. Mater., 35, pp. 225-231 (2005).
  12. S. M. Peper, L. F. Brodnax, S. E. Field, R. A. Zehnder, S. N. Valdez, and W. H. Runde, "Kinetic study of the oxidative dissolution of $UO_2$ in aqueous carbonate media", Ind. Eng. Chem. Res., 43, pp. 8188-8193 (2004). https://doi.org/10.1021/ie049457y
  13. J. N. Sharma, K. Bhattacharya, R. G. Swami, S. K. Tangri, and T. K. Mukherjee, "Studies of the kinetics of $UO_2$ dissolution in carbonate-bicarbonate medium using NaOCl as oxidant", J. Radioanal. Nucl. Chem. Letters, 214(3), pp. 223-233 (1996). https://doi.org/10.1007/BF02163251
  14. Y. Kondo, M. Kubota, T.Abe and K. Nagato, "Development of partitioning method : Recovery and utilization of useful elements in SF (Literature survey)", JAERI-M 91-147 (1991).
  15. J. A. Dean, "Lange's Handbook of Chemistry", 12th Edition, McGraw-Hill Book Co., NewYork (1979).
  16. N. Asanuma, M. Harada, M. Nogami, K. Suzuki, T. Kikuchi, H. Tomiyasu, and Y. Ikeda, "Anodic dissolution of $UO_2$ Pellet containing simulated fission products in ammonium carbonate solution", J. Nucl. Sci. Technol., 43(3), pp. 255-262 (2006). https://doi.org/10.3327/jnst.43.255
  17. A. J. bard, R. Parsons, and J. Jordan, "Standard Potentials in Aqueous Solution", Marcel Dekker Inc. NY (1985).
  18. C. F. Baes, Jr., and R. E. Mesmer, "The Hydrolysis of Cations", Robert E. Krieger Pub. Company, Malabar, Florida (1986).
  19. S. Sunder, D. W. Shoesmith, and N. H. Miller, "Oxidation and dissolution of nuclear fuel $UO_2$) by the products of the alpha radiolysis of water", J. Nucl. Mater. 244, pp. 66-74 (1997). https://doi.org/10.1016/S0022-3115(96)00709-X
  20. N. Asanuma, H. Tomiyasu, M. Harada, Y. Ikeda, and S. Hasegawa, "Anodic dissolution of $UO_2$ in aqueous alkaline solutions", J. Nucl. Sci. Technol., 37(5), pp. 486-488 (2000). https://doi.org/10.3327/jnst.37.486