During the operation, specialists will have to weld 32 joints, as well as install about 260 tons of pipes and metal structures. Welders, installers, flaw detectors, heat treatment specialists and of quality control employees take part in the effort.
All steps are carried out in a strict process sequence, and the results of the control are carefully recorded. Only highly qualified specialists who have undergone dedicated training and qualification are admitted to weld the MCP. Each weld is marked, which allows to trace the full story of its manufacture, control and acceptance. Data on all performed operations are recorded in the as-built documentation and stored throughout the entire life cycle of the power unit.
After welding is completed, each joint undergoes a comprehensive inspection using various methods of non-destructive testing — ultrasonic, liquid penetrant and radiographic. This approach guarantees high reliability of the primary circuit equipment during the entire lifetime of the NPP.
Upon completion of the work, the reactor, steam generators and reactor coolant pumps will be united into the single primary circuit system.
Sergey Kizhapkin, Head of MAW and EIW Coordination Department, T2IC, noted:
“One of the most important stages in welding of the main coolant pipeline is the welding of a pearlitic part 70 mm thick. These works require strict adherence to technology at all stages of the process and special focus the quality of each operation. In the course of the work, a set of inspection activities is carried out with involvement of specialists from various specialized subdivisions”
Grigory Melnikov, Head of Nuclear Island Division, TSM Enerji, stated:
“Every operation, from assembly for welding to heat treatment and non-destructive testing, undergoes a multi-stage inspection with involvement of the relevant services of the general contractor and the customer. The main goal for us is to ensure the quality of weld joints that meet all the requirements of nuclear power engineering.”
The next stage will be high-temperature treatment of weld joints, which allows to remove the internal stress of the metal and ensure the necessary operational characteristics of the pipeline. At the final stage of welding, a special surfacing is applied to the inner surface of the weld joint to protect against corrosion.
Information note from TITAN-2 Holding
TITAN-2 Holding (part of ROSATOM State Corporation) is one of the key participants in large-scale nuclear industry projects in Russia and abroad.
The Holding companies perform a full cycle of work: design, construction organization, construction, electric installation, commissioning of facilities.
Today, TITAN-2 is the general contractor of the construction of new power units of the Leningrad, Kola and Smolensk NPPs, participates in implementation of the PDEC “Breakthrough” project in Seversk, as well as in the largest international nuclear projects – Akkuyu NPP in Türkiye, Paks II NPP in Hungary and El-Dabaa NPP in Egypt.
New power units of the Leningrad NPP and the Kursk NPP-2, the Core Shared Research Facility Siberian Circular Photon Source (SKIF) in Novosibirsk, as well as the facilities of Innopolis in Tatarstan are among the projects completed by the Holding. The competencies of TITAN-2 are also in demand in construction of large industrial, research, social and infrastructural facilities.