Gallery: Sandia pebble-bed reactor simulations
Our group has a fruitful collaboration with the Surface and Interface Sciences department at Sandia National Laboratories. In particular, we make use of a large parallel DEM code developed there for carrying out full physical simulations of granular packings, which we run on our 32-processor Beowulf cluster.
We also analyze data from simulations carried out at Sandia. They have access to approximately three times the computing power, and can carry out much larger simulations, which allows them to examine fully three dimensional situations. This image shows a cutaway of full physical simulation of a proposed pebble-bed nuclear reactor design, with 440,000 particles in a cylinder 58 particle diameters across. As particles flow out of the bottom, they are replaced with new ones poured in from above.
There are two types of particles: the light-colored particles correspond to fuel pebbles, while the dark-colored particles correspond to control pebbles, analogous to control rods in a conventional nuclear reactor. We can obtain extremely accurate information about how much the interface between these two will mix. This question is extremely important to the reactor design, and would be very difficult and costly to answer via experiment.
