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

Modeling and simulation of transient performance of uranium enrichment cascade in the event of a crash of gas centrifuge machines

Document Type : Research Paper

Authors

A.R. Keshtkar 1
A. Rashidi 2
J. Karimi Sabet 1
A. Noroozi 3

1 Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 11365-8486, Tehran – Iran

2 Faculty of Engineering and Technology, University of Mazandaran, P.O.Box: 416, Babolsar - Iran

3 Advanced Technology Company of Iran, AEOI, P.O.Box:14399-55431, Tehran - Iran

https://doi.org/10.24200/nst.2021.1169
Abstract
One of the significant phenomena in the operational conditions of the enrichment cascades is the sudden crash of a number of separate machines along the cascade. In order to investigate the effect of gas centrifuge crash on cascade performance, separation of the cascade in a transient condition should be modeled. In this paper, the performance of two-component symmetric enrichment cascades was modeled, using partial mass balance equations in the transient condition. Nonlinear equations of the model were also discriminated against using Crank Nicholson's finite difference method and the q iteration method was used to solve the equations. The results of the computer simulation of the model cascade for the enrichment of uranium 235 showed that if the crash of gas centrifuge machines occurs at the end of the enrichment part of the cascade, the product concentration will decrease more and more, and it takes a longer time to reach new steady-state condition. For the cascade and the conditions used in this paper, with the crash of a machine, the greatest reduction in product concentration compared to the pre-incident state is, 0.5% percent and the highest increase in waste stream concentration compared to the pre-incident state is 0.2 percent. It was also observed that the cascade performance of machines with a higher separation factor is less affected by the crash of machines. The results showed that the gas hold up has a small effect on the variation of the 235 isotope concentration in the product stream and only affects the time to reach equilibrium in the cascade.

Highlights

1. A. de la Garza, G.A. Garrett, J.E. Murphy, Multicomponent Isotope Separationin Cascades. Chemical Engineering Science, 15(3-4),188–209 (1961).
 
2. P.G. Rousseau, et al, Dynamic Simulation of a Centrifuge Cascade Plant with the Aid of aFlow Network Simulation Code, In Proceedings of the 12th Workshop on Separation Phenomena in Liquids and Gases, June 3-8, (2012).
 
3. J.F.A. Delbeke, et al, The Real TimeMass Evaluation System as a Tool for Detection of Undeclared Cascade Operation atGCEPs. In Proceedings of the 8th International Conference on Facility Operations-Safeguards Interface, Portland, OR, USA, (2008).
 
4. Cohen, The theory of separation as applied to the large –scale production of U235, (1951).
 
5. S. Zeng, C. Ying, A robust and efficient calculation procedure for determining concentration distribution of multicomponent mixture, Sep. Sci.Technol. 35(4), 613–622 (2000).
 
6. S. Zeng, C. Ying, Separating isotope components of small abundance, Sep. Sci. Technol. 37(15), 3577–3598 (2002).
 
7. P.J. Migliorini, H.G. Wood, A Study of Multicomponent Streams in Off-DesignCentrifuge Cascades, Separation Science and Technology, 47(7), 921–928 (2012).
 
8. P.J. Migliorini, H.G. Wood, Transient Operation of a Gas Centrifuge Cascadeto Determine Proliferation Time Frames. In Proceedings of the 12th Workshop on Separation Phenomena in Liquids and Gases, Paris, France, June 3-8, (2012).
 
9. P.J. Migliorini, H.G. Wood, Transient Fluid Dynamics Modeling of GasCentrifuge Enrichment Plants.In Proceedings of the 52nd Annual Meeting of the Institute of Nuclear Materials Management, Palm Desert, CA, USA, July 17-21, (2011).
 
10. P.J. Migliorini, H.G. Wood, Transient Isotope Separation Modeling of GasCentrifuge Enrichment Plants. In Proceedings of the 53rd Annual Meeting of the Institute of Nuclear Materials Management, Orlando, FL, USA, July 15-19, (2012).
 
11. T.H. Benedict, Nuclear Chemical Engineering, New York: McGraw-Will book Co., (1981).
 
12. S. Zeng, C. Ying, Transient process in gas centrifuge cascades for separation of multicomponent isotope mixtures, Sep. Sci. Technol. 36 (15), 3439–3457 (2001).
 
13. S. Zeng, C. Ying, A second-order time-accurate method for determiningthe distribution of concentration distribution of multicomponent mixturesin separation cascades, Sep. Sci. Technol. 35 (5), 729–741 (2000).
 
14. P.J. Migliorini, Modeling and Simulation of Gas Centrifuge Cascades for Enhancing the Efficiency of IAEA Safeguards, May (2013).
 
15. V.D. Borisevich, S. Zeng, On ideal and optimum cascades of gas centrifuges with variable overall separation factors, Chem Eng Sci. (114), 465-472 (2014).

Keywords

Symmetric cascade
Two-component enrichment
Transient simulation
Gas centrifuge crash
Separation factor
1. A. de la Garza, G.A. Garrett, J.E. Murphy, Multicomponent Isotope Separationin Cascades. Chemical Engineering Science, 15(3-4),188–209 (1961).
 
2. P.G. Rousseau, et al, Dynamic Simulation of a Centrifuge Cascade Plant with the Aid of aFlow Network Simulation Code, In Proceedings of the 12th Workshop on Separation Phenomena in Liquids and Gases, June 3-8, (2012).
 
3. J.F.A. Delbeke, et al, The Real TimeMass Evaluation System as a Tool for Detection of Undeclared Cascade Operation atGCEPs. In Proceedings of the 8th International Conference on Facility Operations-Safeguards Interface, Portland, OR, USA, (2008).
 
4. Cohen, The theory of separation as applied to the large –scale production of U235, (1951).
 
5. S. Zeng, C. Ying, A robust and efficient calculation procedure for determining concentration distribution of multicomponent mixture, Sep. Sci.Technol. 35(4), 613–622 (2000).
 
6. S. Zeng, C. Ying, Separating isotope components of small abundance, Sep. Sci. Technol. 37(15), 3577–3598 (2002).
 
7. P.J. Migliorini, H.G. Wood, A Study of Multicomponent Streams in Off-DesignCentrifuge Cascades, Separation Science and Technology, 47(7), 921–928 (2012).
 
8. P.J. Migliorini, H.G. Wood, Transient Operation of a Gas Centrifuge Cascadeto Determine Proliferation Time Frames. In Proceedings of the 12th Workshop on Separation Phenomena in Liquids and Gases, Paris, France, June 3-8, (2012).
 
9. P.J. Migliorini, H.G. Wood, Transient Fluid Dynamics Modeling of GasCentrifuge Enrichment Plants.In Proceedings of the 52nd Annual Meeting of the Institute of Nuclear Materials Management, Palm Desert, CA, USA, July 17-21, (2011).
 
10. P.J. Migliorini, H.G. Wood, Transient Isotope Separation Modeling of GasCentrifuge Enrichment Plants. In Proceedings of the 53rd Annual Meeting of the Institute of Nuclear Materials Management, Orlando, FL, USA, July 15-19, (2012).
 
11. T.H. Benedict, Nuclear Chemical Engineering, New York: McGraw-Will book Co., (1981).
 
12. S. Zeng, C. Ying, Transient process in gas centrifuge cascades for separation of multicomponent isotope mixtures, Sep. Sci. Technol. 36 (15), 3439–3457 (2001).
 
13. S. Zeng, C. Ying, A second-order time-accurate method for determiningthe distribution of concentration distribution of multicomponent mixturesin separation cascades, Sep. Sci. Technol. 35 (5), 729–741 (2000).
 
14. P.J. Migliorini, Modeling and Simulation of Gas Centrifuge Cascades for Enhancing the Efficiency of IAEA Safeguards, May (2013).
 
15. V.D. Borisevich, S. Zeng, On ideal and optimum cascades of gas centrifuges with variable overall separation factors, Chem Eng Sci. (114), 465-472 (2014).

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