OREANDA-NEWS. In the nuclear island reactor building of Leningrad NPP-2 the first power unit main circulation pipeline (MCP) welding has been completed in record time.

To date, work on the first power unit passed into the final phase.

According to the established schedule, the estimated duration of the primary circuit circulation pipeline welding was 140 days. Pearlite welding of all 28 joints was carried out by specialists of MSU-90 in 105 days. 

The main circulation pipeline (MCP) connects the NPP primary circuit equipment: reactor, steam generators and main circulating pumps. It circulates coolant: water temperature of 320°C, pressure up to 17.6 MPa. MCP welding is one of the most important stages in the heating facilities assembly activities during the power units construction. The MCP length is more than 160 meters. Pipelines diameter – 850 mm, wall thickness – 70 mm, and weight is 237 tons. 

Heat treatment of MCP welded joints used both Russian and foreign equipment. To ensure high quality welding of the MCP the welding technology and welders who performed these works have been assessed. 

Completion of the welding allows beginning of installation of systems connected with MCP and participating in the flushing of decompressed reactor, as well as starting the preparation for the assembly of the reactor. 

Background information:

Holding Company TITAN-2 – is the largest group of companies in the North-West, erecting the most important nuclear power and energy facilities. The organizations carry out the full cycle of construction and assembly works: from development of design documentation to commissioning of the facility. Holding Company TITAN-2 is one of the main contractors in construction of units No. 1 and No. 2 of Leningrad NPP-2. 

The Holding Company’s organizations carry out 30 % of civil works and 80 % of assembly works at the construction site. The specialists of the Holding Company are working at the first and the second unit facilities of the Leningrad LNPP-2. The works are currently carried out in the reactor, turbine, electric power supply, water supply, district heating buildings and other structures of the units.