Physicists from the Moscow Institute of Physics and Technology (MIPT) and the Joint Institute for High Temperatures (JIHT) of the Russian Academy of Sciences have described the mobility of line defects, or dislocations, in uranium dioxide. This, they announced this week, will enable future predictions of nuclear fuel behaviour under operating conditions.
Their research findings have been published in the International Journal of Plasticity and they are looking for international collaboration to speed up the potential application of their work in the commercial and regulatory nuclear spheres.
In their paper, the scientists - Artem Lunev, Alexey Kuksin and Sergey Starikov - provide data of a simulation of dislocation behaviour in uranium dioxide, which is one of the most widespread compounds used as nuclear fuel in power plants. They say it is the first time that dislocation mobility in uranium dioxide at high temperatures and under stress has been studied in detail.
Dislocation dynamics work to determine fuel properties relevant to nuclear engineering, including plasticity and fission fragments diffusion. The scientists used computational methods to develop a model of an isolated dislocation in a perfect uranium dioxide crystal. They calculated the varying dislocation velocity as a function of temperature and the external forces affecting the crystal.
Specifically, they have produced a model that can be used to calculate dislocation velocity based on known temperature and stress parameters. This could be used to simulate more complex systems and study the macroscopic processes occurring in fuel pellets under operating conditions. They suggest this is a major advance toward being able to describe processes as complex as nuclear fuel swelling and embrittlement during operation by means of computer simulations alone.
click link for full article
http://www.world-nuclear-news.org/UF-Russian-scientists-claim-breakthro…