Cycle specific hot channel analysis with TRANSURANUS

The aim of the PWR hot channel analysis in the German regulatory framework is to prove that for any conceivable transient in the normal operating domain the fuel temperature stays below the melting temperature and the transient tangential cladding strain remains below its licensing limit. In this paper we demonstrate a methodology on how to prove the requirements of the hot channel analysis on a cycle specific basis. In the first step a limit boundary curve is calculated for the maximum rod peak power as a function of burnup for the melting temperature criterion. A limit boundary plain is calculated for the maximum rod power jump as a function of burnup and pre-transient power level for the strain criterion. These boundary sets are considered to be cycle independent. In the second step a standardized and demanding reactor transient is analyzed for a specific cycle. The maximum rod peak powers and maximum rod power jumps are compared with the limit boundary sets in order to prove the above mentioned licensing requirements. Calculation results for the boundary sets are presented for a 4000 MWth PWR core loaded with Opt. Zirlo U/U-Gd 16x16 fuel assemblies. These results were derived with the help of the computer code TRANSURANUS. The transient fuel parameters were calculated with the CASCADE-3D computer code. (orig.)