Laser Heating Study of the High-Temperature Interactions in Nanograined Uranium Carbides

Nanograined nuclear materials are expected to have a better performance as spallation targets and nuclear fuels than the conventional ones, but many basic properties of such materials are still unknown. The present work aims to contribute to their better understanding by studying the effect of grain size on the melting and solid-solid transitions of nanograined UC2-y. 4 nm-10 nm grain size samples with UC2-y as the main phase, but containing graphite and UO2 as impurities, were laser-heated under inert gas to temperatures above 3000 K and their behavior was studied by thermal radiance spectroscopy. The UC2-y solidification point (2713(30) K) and α-UC2 to β-UC2 solid– solid transition temperature (2038(10) K) were observed to remain unchanged, when compared to bulk crystalline materials with micrometer grain sizes. After meltdown, the composite grain size persists at the nanoscale, from around 10 nm to 20 nm, pointing to an effective role of carbon on preventing the rapid diffusion of uranium and grain growth.

CHOWDHURY S.;  MANARA Dario;  DIESTE BLANCO Oliver;  ROBBA Davide;  PEREIRA GONÇALVES Antonia; 

2021-11-23

MDPI

JRC126307

1996-1944 (online),   

https://www.mdpi.com/1996-1944/14/19/5568,    https://publications.jrc.ec.europa.eu/repository/handle/JRC126307,   

10.3390/ma14195568 (online),