Reactor coolant pipeline (RCPL) connects the main equipment of the reactor plant, such as the reactor, steam generators, reactor coolant pumps, and generates the NPP primary circuit. Pipeline length is 160 metres, thickness is 7 centimetres. Coolant at a temperature of 330 degrees Celsius under pressure of 160 atm. will circulate in the RCPL at the NPP operation stage.

Installation of the reactor coolant pipeline includes not only assembly and welding of pipes, but also high-temperature treatment of joints, after which special surfacing is applied to them from the inside of the pipeline. It provides the pipeline with corrosion protection characteristics, increases strength of weld joints and ensures the pipeline operation life time of at least sixty years provided for in the design.

Specialists are required to weld 28 pipeline joints and mount approximately 260 t of pipes and steel structures in total, as well as to ensure the quality control of the weld joints performed. A step-by-step monitoring of all operations as follows is performed during welding: visual, dimensional, radiographic, liquid penetrant and ultrasonic testing. Quality Control Service carries out the acceptance of each component prepared for welding to ensure that the parts comply with the established requirements.

In general, the welding quality control is carried out in several stages and includes independent ways of control as per the adopted rules and regulations.

“Employees performing quality control shall meet the highest qualification requirements. Only professionals who passed strict qualification testing are allowed to perform such works,” noted Aleksey Mezhiritskiy, Program Director of the Russian-Turkish Joint Venture TITAN2 IC İÇTAŞ İNŞAAT ANONİM ŞİRKETI, the main Contractor for the Akkuyu construction.

The next key operation at the construction site of the Akkuyu NPP first Power Unit will be the operation of flushing into the open reactor, during which pipelines flow ability will be checked, their pre-installation cleaning conducted, and readiness of equipment to first criticality stage confirmed.


Reference Information:

The TITAN-2 holding is a Russian group of companies that builds nuclear facilities. Organisations of the holding perform the whole cycle of works, from development of the design documentation to facility commissioning.

The TITAN-2 holding is the general contractor for construction of the new power units of the Leningrad NPP. At the construction site, the organisations of the holding perform all civil construction, installation, and electric installation works.

The holding participates in construction of the Akkuyu NPP in Turkey, Paks-2 NPP in Hungary and El-Dabaa in Egypt.