Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Mathematical Modeling and Simulation of Fluorination Reaction of Uranium Dioxide and Evaluation of Existing Gas-Solid Reaction Models

Document Type : Research Paper

Authors

A Niksiare
A Rahimi
Abstract
In this study a mathematical model is developed in order to simulate fluorination reaction of uranium dioxide leading to produce uranium hexafluoride. The model considers homogeneous reaction for intermediate solid and heterogeneous one for unreacted shrinking core. Also, this study tries to clearly show the shortcoming of those foregoing models that take surface reactions for both solids. In fact, one may not trust the accuracy of those models due to ignoring the importance of the diffusion phenomena into the intermediate solid and taking place the reaction within it. On the other hand, by neglecting the undeniable effects of operating conditions, including temperature and particle size on gas concentration distrbution and reaction rates may introduce large deviations. For this mentioned purposes, the governing equations are derived on the basis of the mass conservation law and have been solved numerically. Besides, for the first time, some dimensionless equations and groups are introduced to predict the reaction rates and the amount of the main and the intermediate products for using numerical procedure. Comparing the results with the corresponding experimental ones represents the desirable accuracy of the model. After validation of the model, the effect of some operational variables such as temperature and initial particle size have been investigated on the reaction rates and the conversions.
 

Highlights

  1. 1.    E.L. Cussler, “Diffusion mass transfer in fluid systems,” Cambridge university press, (2003).

 

  1. 2.    O. Levenspiel, “Chemical reaction engineering,” 3th ed., John Wiley $ Sons, New York, (2001).

 

  1. 3.    S. Ogata, S. Homma, A. Sasahira, F. Kawamura, J. Koga, S. Matsumoto, “Fluorination reaction of uranium dioxide by fluorine,” Journal of  Nuclear Science and Technology, 41, 135-141 (2004).

 

  1. 4.    T. Yahata and M. Iwasaki, “Kinetic studies of the fluorination of uranium oxides by fluorine-part II,” Journal of Inorganic Nuclear Chemistry, 26, 1863-1867 (1964).

 

  1. 5.    S. Ogata, S. Homma, J. Koga, S. Matsumoto, “Gas-solid reaction model for a shrinking spherical with unreacted shrinking core,” Journal of Chemical Engineering Science, 60, 4971-4980 (2005).

 

  1. 6.    T. Sakurai, “Comparison of the fluorination of uranium dioxide by bromine trifluoride and elemental fluorine,” Journal of Physical Chemistry, 78, 1140-1144 (1974).

 

  1. 7.    ا. رحیمی و ا. نیک سیر، ”بررسی دقت مدل هسته واکنش نداده کوچک شونده در مدلسازی و شبیه‌سازی تبدیل دی‌اکسید اورانیوم،“ نخستین همایش بین‌المللی جایگاه چرخه سوخت هسته‌ای در توسعه علوم و فناوری، اصفهان (1385).                                                          
  2. 8.    P.A. Ramachandran and L. K. Doraiswamy, “Modeling of noncatalytic gas-solid reactions,” AIChE Journal, 28, No. 6, 881-900 (1982).

 

  1. 9.    S.K. Bhatia and D.D. Perlmutter, “A random pore model for fluid-solid reactions: II. Diffusion and transport effects,” 27, No. 2, 247-254 (1981).

 

  1. 10.              V. Stratis Sotirchos and Huei-Chung Yu, “Mathematical Modeling of gas-solid reactions with solid product,” Chemical Engineering Science, 40, No. 11, 2039-2052 (1985).

 

  1. 11.              S.S. Sazhin and A.P. Jeapes, “The analytical and numerical study of the fluorination of uranium dioxide particles,” Journal of Nuclear Materials,  249, No. 2-3, 207-222 (1997).

 

  1. 12.              W.E. Ranz and W.R. Marshall, “Evaporation from drops,” Chemical Engineering Progress, 48, 173-180 (1952).

Keywords

Gas-Solid Reaction
Fluorination of Uranium Dioxide
Mathematical Modeling and Simulation
  1. 1.    E.L. Cussler, “Diffusion mass transfer in fluid systems,” Cambridge university press, (2003).

 

  1. 2.    O. Levenspiel, “Chemical reaction engineering,” 3th ed., John Wiley $ Sons, New York, (2001).

 

  1. 3.    S. Ogata, S. Homma, A. Sasahira, F. Kawamura, J. Koga, S. Matsumoto, “Fluorination reaction of uranium dioxide by fluorine,” Journal of  Nuclear Science and Technology, 41, 135-141 (2004).

 

  1. 4.    T. Yahata and M. Iwasaki, “Kinetic studies of the fluorination of uranium oxides by fluorine-part II,” Journal of Inorganic Nuclear Chemistry, 26, 1863-1867 (1964).

 

  1. 5.    S. Ogata, S. Homma, J. Koga, S. Matsumoto, “Gas-solid reaction model for a shrinking spherical with unreacted shrinking core,” Journal of Chemical Engineering Science, 60, 4971-4980 (2005).

 

  1. 6.    T. Sakurai, “Comparison of the fluorination of uranium dioxide by bromine trifluoride and elemental fluorine,” Journal of Physical Chemistry, 78, 1140-1144 (1974).

 

  1. 7.    ا. رحیمی و ا. نیک سیر، ”بررسی دقت مدل هسته واکنش نداده کوچک شونده در مدلسازی و شبیه‌سازی تبدیل دی‌اکسید اورانیوم،“ نخستین همایش بین‌المللی جایگاه چرخه سوخت هسته‌ای در توسعه علوم و فناوری، اصفهان (1385).                                                          
  2. 8.    P.A. Ramachandran and L. K. Doraiswamy, “Modeling of noncatalytic gas-solid reactions,” AIChE Journal, 28, No. 6, 881-900 (1982).

 

  1. 9.    S.K. Bhatia and D.D. Perlmutter, “A random pore model for fluid-solid reactions: II. Diffusion and transport effects,” 27, No. 2, 247-254 (1981).

 

  1. 10.              V. Stratis Sotirchos and Huei-Chung Yu, “Mathematical Modeling of gas-solid reactions with solid product,” Chemical Engineering Science, 40, No. 11, 2039-2052 (1985).

 

  1. 11.              S.S. Sazhin and A.P. Jeapes, “The analytical and numerical study of the fluorination of uranium dioxide particles,” Journal of Nuclear Materials,  249, No. 2-3, 207-222 (1997).

 

  1. 12.              W.E. Ranz and W.R. Marshall, “Evaporation from drops,” Chemical Engineering Progress, 48, 173-180 (1952).

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