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At least 649 records · Page 36

Entrapment Behavior of Solid Surrogate Fission Products at Engineered UN Nano‐Hetero‐Interfaces Within Metallic Nuclear Fuels

Nanometric hetero-interfaces provide a wealth of scientific and engineering opportunities due to their complex and often misunderstood properties that can differ from their respective bulk constituents. In this work, the ability for engineered nanostructures within a bulk U─Mo alloy to arrest simulant fission products is investigated experimentally and computationally. Nanostructured 90 wt% U/ 10 wt% Mo (U-10Mo) with 7.1 at% Nd is consolidated using spark-plasma- sintering (SPS) techniques and is heat-treated at 500 °C under vacuum for 24, 100, 500, and 1000 h. Analysis on the sintered and heat-treated U-10Mo reveals rapid kinetics in Nd diffusion to nanocluster sites, with evidence of Nd diffusion occurring during sintering and during the following heat-treatment. The segregation behavior of Nd at two different U─Mo/UN interfaces is computationally verified using density functional theory (DFT) to reinforce experimental data.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Generating aerodynamic surrogate nuclear explosion debris (SNED)

So called “aerodynamic debris” has often been observed from explosion debris collected on the fringe of surface nuclear tests, and is assumed to result from ejection of melted and re-condensing ground materials drawn up into the rising explosion fireball. The material forms small glassy particulates measuring ~1mm, ranging in shape from near perfectly spherical glassy beads to more elongated forms and occasionally agglomerates of two or more particles displaying some degree of fusion. Producing material with a similar range of characteristics in the laboratory may be quite challenging, as the temperatures required can exceed 1500°C while keeping the particulates suspended in constant motion. In this paper we describe an apparatus that can heat lofted sediment particulates up to 1mm very rapidly above their melting points, allowing extended interactions times from seconds to minutes. Examples of the different material forms produced will be compared to real aerodynamic debris recovered from nuclear explosions described in the literature.

Liezers, M.↗