Nuclear graphite friction properties and the influence of friction properties on the pebble bed

Recently, the role of friction and wear in the safety of pebble bed reactors was reconsidered. The friction properties of graphite were analyzed in this paper. In the first part of this paper, we investigated the past research of graphite and analyzed the influence of environment gas, temperature and radiation on friction coefficient. The variation laws of friction coefficient with the effect factors were given, especially in helium environment (including pure helium and HTGR helium). In the second part, the mechanical behavior of pebble bed is discussed while considering the influence of the friction properties of graphite. The results indicated that the fuel elements cannot be crushed failure even though the fuel elements have a large friction coefficient.

Research highlights▶ The friction properties of graphite. ▶ Pebble bed. ▶ High temperature gas-cooled reactor. ▶ Fuel element.