The code athlet as a valuable tool for the analysis of transients with or without scram in PWR's

The GRS system code ATHLET will be presented as an efficient tool for the analysis of plant internal events. It can be used for postcalculations of both anticipated or abnormal transients but also small or large break accidents. The code is based on a highly modular and thus very flexible network structure, the structure requiring a very complex input data set arrangement. Different rules can be applied to compile a distinct and clearly understandable input data set. One such procedure will be discussed in the paper. The ability of the code and the proposed procedure will be demonstrated on two transient cases