The main circulation piping connects the equipment of the first NPP loop, so the welding of the main circulation piping is one of the most important stages of the thermal installation works at the power unit construction.

The piping length is 160 meters, design life – 60 years. The temperature of inside circulating water will be 320 °C.

108 days were reserved to complete the scheduled works. The specialists of JSC MSU-90, TITAN-2 holding subsidiary company, accomplished welding of the perlite part of all 28 joints in 85 days. All piping elements are connected to each other and welded to the reactor pressure vessel, steam generators and the main circulation pumps.

«The works execution period shortened through well-organized technological process, optimization of heating operations for welding and heat treatment of joints. And most importantly, participation of high-skilled specialists from MSU-90 with experience in welding of the main circulation piping at Unit 1 of LNPP», said the Chief Engineer of LNPP under construction, Alexander Belyaev.            
The entire scope of works for the main circulation piping will be completed before the end of month. To date, NTD inspection of all the welded joints is in progress. Once the welding of the main circulation piping is completed, the preparation works for the reactor assembling at the second power unit will start.


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.

The Holding is the main contractor for the construction of the Hanhikivi-1 NPP in Finland.