Investigation of Separation Factor of gas diffusion system for UF6 by Direct Simulation Monte Carlo method

Document Type : Research Article


Department of Nuclear engineering, Faculty of Fuel cycle, Shahid Beheshti University, Tehran, Iran


The aim of this article is to investigate the effect of the flow regime type, Knudsen number on the formation of separation and separation factor in the gaseous diffusion system. And also investigation of diffusion velocity of particle across the pores of membrane. In the present article, first, a brief description of the theory governing the system is given. Then, a model of an element is defined for above system. After modeling, first the results of the effects of the flow regime type on the variation of enrichment are shown. Also the effects of increasing the Knudsen number on the separation factor is investigate. Finally, the diffusion velocity of each gas component will be shown inside the pores and all of this results will be compared with theory of system. It should also be noted that two light and heavy UF6 gas isotopes have been used for gas separation.
The results will show; Separation does not take place in the continuous flow regime, and separation will have occurred only in the molecular and transient flow regime. Also, as the Knudsen number increases, the variation of enrichment in different parts of the system will increase compared to the inlet gas. In other words, as the Knudsen number increases, more separation occurs and the system separation factor increases. For example, in Knudsen number 0.1, separation factor is 1.00101, and in Knudsen number 0.8 this value will increase to 1.00333. Finally, diffusion velocity of particle inside the pores has been investigated, which that is a criterion for the effective separation. The results indicate that the particle diffusion velocity for the light component is higher than heavy component, and this is due to passing the high count of light particle through inside the pores than heavy component.


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