Application of coupled code method for the analysis of VVER-1000 coolant transient benchmark

In the light of the sustained development in computer technology, the possibilities of code capabilities have been enlarged substantially. Consequently, advanced safety evaluations and design optimizations, which were not possible few years ago, can now be performed. Nowadays, it becomes possible to switch to new generation of computational tools, namely, coupled code (CC) technique. The application of such method is mandatory for the analysis of transient events where strong coupling between the core neutronics and the primary circuit thermal-hydraulics exits, and more especially when asymmetrical processes take place in the core leading to local space-dependent power generation. Through the current study, a demonstration of the maturity level achieved in the calculation of 3-D core performance during complex accident scenarios is emphasized. The study is followed by a typical application through which the main features and limitations of this technique are discussed