Test calculations by new version of C-PORCA

During next years new kinds of fuel assemblies will be introduced at the NPP Paks. Regular usage of these fuel assemblies indicates a few questions about applicability and accuracy diffusion model applied to core analysis during in-core fuel management and core surveillance. A more accurate and reliable calculation is needed of the pinwise power and indicate the need of its more reliable validation. To achieve the aimed requirements two main developments have been carried out in the C-PORCA code. To validate the accuracy of the thermal model the Helios code was used again. The fulfilled modifications in the C-PORCA code, focused on the enhancement of the accuracy of the code in the vicinity of the control assemblies especially next to the connection area between the follower and the absorber parts. (author)