63 horizontal tendons of the inner containment pre-stressing system were installed in the reactor building.

They are laid through special holes - tendon sheaths – and fully encircle the inner containment horizontally.

Ring (horizontal) tendons are located in the cylindrical part of the containment and in the lower tier of the dome. Each tendon contains 55 high-strength pre-stressing strands with 15.2 diameter in the PE sheath.

Total of 750 tons of the pre-stressing strands was installed. The strands were “inserted” into the 63 horizontal tendon sheaths with the average length of 155 meters.

The technology was developed by the STS Ltd engineers and executed by the JSC “Concern Titan-2” specialists, which allowed to install up to 2 strands weighing 13 tons each a day.

The next stage is concreting of the tendon sheaths already filled in with the inner containment tendons. Then the specialists will commence installation of 50 vertical and 13 dome tendons.


Titan-2 Holding is the largest in the North-West group of companies, constructing the most important nuclear industry and power facilities. The company performs a full range of construction and installation works from engineering to commissioning.

Titan-2 Holding is the general contractor for the construction of the Leningrad NPP-2 power units. The Holding Companies perform all the civil, installation, and electrical works at a construction site. The works are carried out in the reactor, turbine, power supply, water supply, heat cogeneration buildings and other power unit structures.