Specialists have completed welding at the main circulation pipeline (MCP) of unit 1 at the Akkuyu NPP under construction in Turkey, project company Akkuyu Nuclear said on 1 June. All 28 joints of the were welded on schedule between 19 March and 25 May after which an awards ceremony was held for the workers and specialists involved. The works was carried out by the main contractor for the construction of the Akkuyu NPP, the joint venture Titan2 IJ Ichtash Inshaat Anonim Shirketi. Quality control was overseen by by specialists from Akkuyu Nuclear JSC, the Turkish Nuclear Regulatory Agency (NDK) and independent building control organisation Assystem.
After the welding of each seam, the welded joints were examined using ultrasonic, capillary and other methods of control. In parallel with welding, heat treatment of the joints was performed. At the next stage, specialists will make special stainless steel overlays on the inner surface of the seams, which will serve as additional protection for the pipeline walls.
Akkuyu Nuclear General Director Anastasia Zoteeva presented special certificates to 29 people “Qualified and experienced specialists showed well-coordinated and efficient work at all stages of the MCP installation: from pipeline assembly, welding, high-temperature processing of seams to quality control of welded joints,” she said. “We can confidently say that an important step has been taken towards our main goal - the launch of the first unit at the Akkuyu NPP.” She thanked everyone involved for their “responsible and diligent work, highest professionalism and efficient organisation of all the technological processes”.
The MCP is 160 metres long with walls made of 7-centimetre-thick special steel. During the operation of the NPP, primary circuit coolant will circulate in the MCP - deeply demineralised water with a temperature of up to 330 degrees Celsius at a pressure of 160 atmospheres. This is kept separate from the sea water in the secondary circuit. The thermal energy that is produced in the reactor is transferred through the heat exchange tubes of the steam generator from the primary to the secondary circuit to produce saturated steam which is fed to the turbine to generate electricity.
Image: Rosatom has completed welding of the main circulation pipeline at Akkuyu NPP's unit 1 (Source: Akkuyu Nuclear)