Preliminary Study on UF6 Leakage Source Term in Restricted Space

Abstract

Uranium hexafluoride ($UF6$) is an intermediate substance in the uranium fuel cycle process. It has been widely used in uranium conversion plants, uranium enrichment plants, and nuclear fuel element plants. Unlike the outdoor leakage of UF6, the isolation function of the plant and the air filtration system will effectively control the UF6 and its hydrolysates in the plant when leakage occurs. UF6will react chemically and diffuse simultaneously in the plant. For the workers in the plant, Accidents are more likely to cause injury. Based on the release path and leakage process of UF6, this paper comprehensively considers the flash, diffusion, and sedimentation processes of UF6, and a UF6leakage source term model in the confined space is finally established. The model decomposes the release process of UF6in the confined space into several nodes. The substance and energy of each component can be obtained through the steady and transient calculation of UF6and its hydrolysates in nodes. Finally, the spatial distribution of UF6 and UF6 hydrolysates in the entire confined space in different time intervals can be obtained.