A 2D (R-Z) thermal-mechanical model for analysis of Generation-IV Gas-cooled Fast Reactor (GFR) plate-type fuel has been coupled to the system behaviour code (TRACE) and applied for the investigations of reactor transient behaviour. The 2D fuel model was earlier benchmarked against 3D finite-elements modelling (done with the ANSYS code). A number of unprotected GFR transients have currently been considered, and reliable results (compared to simplified TRACE modelling) are obtained for the GFR fuel stress-strain conditions and the temperature field within the cell.
The comparison of results between the two models has shown that accounting for the honeycomb-structure geometry of the fuel has significant influence on the peak and average fuel temperatures. The net effect, however, is mitigated by compensating differences in results when simulating the fuel deformation. The latter statement is of course only valid for the specific fuel dimensions considered.