A review of recent study on the characteristics and applications of pebble flows in nuclear engineering

This paper reviews the recent three-year progress on the investigations of pebble bed flows in nuclear engineering. Both the application of pebble beds in the fission reactors and the fusion reactors are included. The fundamental characteristics of packing, flows, conduction, convection, radiation, and the effective thermal conductivity of pebble beds are reviewed. The important issues on the design of the pebble beds as well as that related to the reactor safety are also introduced. In addition, the advances in measurement techniques and numerical coupled methods for exploring the pebble flow characteristics are categorized and summarized too.