Welding of the main circulation pipeline completed at Akkuyu NPP Unit 1
June 1, 2022, Buyukeceli, Turkey. – Another important stage is completed within Akkuyu NPP Unit 1 construction. Main circulation pipeline (MCP) welding, which had started on March 19, 2022, was finished on May 25. Within 68 days, the specialists welded all 28 joints of the pipeline.
On the occasion of the MCP welding completion, a ceremony was held at the Akkuyu NPP construction site, to award the workers and specialists who were directly involved in the welding and control operations.
29 people were awarded with memorable souvenirs and certificates of appreciation by AKKUYU NUCLEAR JSC CEO Anastasia Zoteeva, with a note “For successful participation in the welding works of Akkuyu NPP Unit 1 main circulation pipeline”. Among the awarded employees were managers of the subcontracting organizations, welders, non-destructive testing operators, assemblers and other specialists who had fulfilled complex technological operations at a high professional level and completed welding within the time frame stipulated by the project schedule.
The complex of the welding works was carried out by the main Akkuyu NPP construction contractor, the joint venture TITAN2 IC İÇTAŞ İNŞAAT ANONİM ŞIRKETİ. The quality of works and compliance with strict performance requirements were controlled by experts from AKKUYU NUCLEAR JSC, Nuclear Regulatory Authority (NDK) of Turkey and ASSYSTEM, an independent construction control organization.
On completion of the welding works on each seam, non-destructive testing operators assessed the quality of the welded joints using ultrasonic, capillary, and other control methods. The heat treatment of the joints was conducted in parallel with the welding works. At the next stage, specialists will have to make special stainless-steel overlays to cover the inner surface of the seams which will serve as an additional protection for the pipeline walls.
“The best of the best are working at the Akkuyu NPP project! Qualified and experienced specialists showed well-coordinated and efficient work at all stages of MCP installation. All the works, starting from pipeline assembly, welding, high-temperature processing of seams and including quality control of the welded joints, have been conducted at a high professional level. We can say for sure that we have taken a significant step towards our main goal, commissioning of Akkuyu NPP Unit 1. I would like to thank everyone who was involved in the welding works for their responsibility and diligence, highest professionalism and well-structured organization of all technological processes. Akkuyu NPP project team is proud of you!” said AKKUYU NUCLEAR JSC CEO Anastasia Zoteeva, addressing the team of the welders during the award ceremony.
The length of the MCP is 160 meters. The wall thickness of the pipe made of special steel is 7 centimeters. At the NPP operation stage the coolant, i.e. deeply demineralized water up to 330 degrees Celsius at a pressure of 160 atmospheres, will circulate in the MCP. Water circulating in the MCP does not intermix with seawater in any way.
Thermal energy produced in the reactor is to be transferred through the steam generator heat exchange tubes from the first circuit to the second one. It will result in producing saturated steam. Through the steam pipeline, it will enter the steam turbine, which sets the generator in motion to produce electricity.