In order to reduce the construction timeframe of Units 5 and 6, the installation of the large-size equipment (Reactor, Steam Generators, the Emergency Core Cooling System, etc.) was performed by the method of open installation (without containment cover) instead of the foreseen according to the project installation using the regular polar crane.
The experience of the operation of similar NPP in Russia and Ukraine showed the necessity of the Steam Generators Replacement because of problems with water chemistry at their plants, as well as structural defects of the steam generators. At the Kozloduy NPP, these structural defects were removed before the commissioning of the Units (finish-rolling of the tubes and header gaps). Nevertheless, according to 51111 Modernization Program Measure, the Steam Generators Replacement Project was developed.
The purpose of this project was to verify the actual over-all dimensions and elevations, and whether this replacement can be done with the regular polar crane. In the framework of the project process charts for the performance of separate activities have been developed with a budget for each activity.
The result of the project showed that this activity is possible and can be performed, if necessary, within the 6-8 months.