New generation first-of-the kind unit – VVER-1200 design features

The paper is concerned with the commissioning of the new generation NPP-2006 power unit with the VVER-1200 reactor. A comparison is made between the characteristics of the new NvNPP II-1 and commercial VVER-1000 power units (B-320). Some design and circuit solutions used in the NPP-2006 project were described, which made it possible to increase the installed capacity of the power unit, which was achieved, in particular, by increasing the pressure of the primary circuit by 0.5 MPa and the pressure in the steam generators by 0.6 MPa, and also by increasing the capacity of the main circulation pumps by 2000 m3/h. The main differences in the equipment and composition of passive and active safety systems of the NPP-2006 power unit are considered. A brief description of the safety systems first applied at Russian power units is given, e.g., a two-channel structure of active safety systems with redundant emergency pumps in each channel, a double containment, a core melt localization device, a passive heat removal system, etc. Due to the increased number of BRU-Ks, it was possible to increase their performance from 15 to 3 s, which significantly improved the maneuverability of the power unit in abnormal conditions. The structure of the APCS is considered, which is applied in the NPP-2006 project, using programmable technology based on the TELEPERM XS platform. The peculiarities of the power unit commissioning are analyzed, problematic issues that have arisen at various stages of the construction are revealed, some data on the tests carried out and the results of these tests are given. Finally, an analysis is made of some design drawbacks revealed during the construction and commissioning of the power unit, an evaluation of the project was made, and proposals were formulated to finalize the VVER-1200 project for consideration in the subsequent NPP projects.