Impact of fine particles on rheological properties of uranium dioxide powders - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Access content directly
Journal Articles Nuclear Engineering and Design Year : 2020

Impact of fine particles on rheological properties of uranium dioxide powders


In industry, the use of powders is very common. Understanding granular flow in silos, hoppers or pneumatic conduits is necessary. This study investigates the characterization of the rheological properties of uranium oxide powders in the context of a powder metallurgy process for nuclear fuel pellets manufacturing. The flow and arrangement properties of these powders must be compatible with a reproducible feed of press moulds. This may require a modification of the physical characteristics of the powders. In particular, particle size is known to have a great impact on the rheological properties and a significant effect of fine particles (less than 100 µm) is suspected. In this study, we have quantified this influence of particle size distribution on rheological properties of UO2 powders, especially the influence of the amount of fine particles. Two complementary approaches have been used. The first approach is to characterize the powder in a static state: the density, compressibility and shear measurements make it possible to understand the behaviour of the powder when it is moved from static state to dynamic state. The second approach is to characterize the behaviour of the powder in the dynamic state. It allows understanding the flow capacity of a powder in the process. To answer the problem of reproducible filling of the press moulds, it is essential to characterize the two regimes, that is to say the flow of the powder from a hopper or a shoe, then the behaviour in the dynamic state. The amount of fine particles has been more especially varied because the cohesive forces are considered predominant with respect to gravitational forces for particles smaller than 100 μm. A threshold of the rate of fines has been demonstrated in both types of measurements. Beyond this threshold, the behaviour of the powder is approximatively the same.
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cea-02339845 , version 1 (17-03-2020)



A. Madian, K. Saleh, C. Ablitzer, P. Matheron, M. Leturia, et al.. Impact of fine particles on rheological properties of uranium dioxide powders. Nuclear Engineering and Design, 2020, 52, pp.1714-1723. ⟨10.1016/⟩. ⟨cea-02339845⟩
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