Welding completed of main circulation pipeline in unit 1 of Turkey’s first nuclear plant  

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The work of welding the main circulation pipeline in unit 1 of Turkey’s first nuclear power plant (NPP) at Akkuyu, being constructed with the assistance of the Russian state atomic energy corporation Rosatom, was completed on May 25, 2022.  

According to a Rosatom statement, the work of welding all the 28 joints of the main circulation pipeline, begun on March 19, 2022, took 68 days to complete. 

The main circulation pipeline connects the major equipment of a nuclear power plant – reactor, steam generators, reactor coolant pumps – and is a part of the primary circuit of an NPP.   

“On the occasion of the main circulation pump (MCP) welding completion, a ceremony was held at the Akkuyu NPP construction site, to award the 29 workers and specialists who were directly involved in the welding and control operations”, the statement said.   

“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”, it added.  

Addressing the team of the welders during the award ceremony Rosatom subsidiary Akkuyu Nuclear’s CEO Anastasia Zoteeva said: “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.” 

The welding of the main circulation pipeline is one of the key stages in the construction of the reactor unit.  

“During the NPP operation, water at a temperature up to 330 degrees Centigrade continuously circulates through the MCP. Only special pipes with 70 mm wall thickness can withstand such loads, therefore, pipeline welding is a complex and high-tech operation, which is subject to the most stringent requirements. The completion of the welding operation will be the starting point for open reactor circulation tests”, an earlier Rosatom statement had said.  

The statement said the installation of the main circulation pipeline includes not only assembly and welding of pipes, “but also high-temperature treatment of joints followed by a special build-up welding on the inside of the pipeline”. This provides corrosion resistance to the pipeline, increases durability of welded joints and ensures the pipeline’s operating lifetime of at least sixty years, as stipulated by the project design.    

Last year, the reactor pressure vessel was installed at unit 1 of the Akkuyu NPP. Rosatom had also announced that construction work had started on units 3 and 4 of the Akkuyu NPP. A Rosatom statement had said that building and installation works were being carried out simultaneously at the construction sites of all four Akkuyu NPP power units, making it the world’s largest nuclear construction site with four power units being built simultaneously.  

The statement had also said that the Akkuyu NPP is the first project in the global nuclear industry that is being implemented according to the Build-Own-Operate model.  

According to Turkish Energy and Natural Resources Minister Fatih Dönmez, “construction and commissioning of the plant will provide 10 percent of Turkey’s electricity needs. It is also an important contribution to the preservation of our ecology: nuclear power plants are a source of environmentally friendly and uninterrupted electricity. The project is a driver for the development of industry, economy, employment, and also contributes to the development of many related industries.”       

Turkey plans to bring the 1,200 MW unit 1 online in 2023. With three more similar units, the Akkuyu NPP will have a total capacity of 4,800 MW. All the units are to be equipped with the Russian designed Generation III+ VVER-1200 reactors.