Another critical stage for the 4th Power Unit of Akkuyu Nuclear Power Plant (NPP), Türkiye’s first nuclear power plant (NPP) project, has been successfully completed. Atommash, a long-established facility affiliated with the mechanical engineering department of Rosatom, the Russian State Nuclear Energy Corporation, has reached an important milestone in the delicate work it has carried out regarding the production of the nuclear reactor vessel. The facility has successfully completed the welding process, which is considered one of the most difficult and critical processes in the manufacturing process of the reactor vessel.
Challenging Welding Process Completed Successfully
The welding process applied during the assembly of the nuclear reactor vessel is known to be a process that requires high precision and expertise. During this meticulous work, which lasted approximately 10 days, the welded area was continuously heated to a precise temperature between 170 and 280 degrees Celsius. More than 1,2 tons of special welding arc and 1 ton of welding wire were used in this difficult process. Completion of the welding process is of vital importance in ensuring the integrity of the reactor vessel.
Quality Control Processes Ensure Safety
After welding, the reactor vessel will undergo a series of rigorous checks and tests. First, heat treatment will be applied to eliminate possible stresses in the vessel’s internal structure. Then, the vessel’s flawlessness will be confirmed by comprehensive non-destructive testing methods, such as radiographic flaw detection, ultrasonic testing and crack control with special paints. The safe and long-term operation of the nuclear power plant (at least 60 years) directly depends on the quality of the welded joints of the reactor equipment.
The Heart of Akkuyu NPP is Being Put Into Place
The production of the nuclear reactor vessel is a long process that involves meticulous, high-tech operations carried out by experts and lasts several years. Three of the four power units of Akkuyu NPP are equipped with the reactor vessel, the most basic and vital element of the reactor unit. In the near future, the 4th Power Unit will also receive this critical equipment, which is considered the “heart” of the nuclear reactor.
Statements from Rosatom and AKKUYU NUCLEAR A.Ş.
Regarding the completion of the reactor vessel welding, Sergei Butckikh, General Manager of AKKUYU NUCLEAR A.Ş., said, “The completion of the reactor vessel welding for the 4th Power Unit of Akkuyu NPP indicates that Atommash has completed one of the labor-intensive and long-cycle operations to produce reactor equipment for the first NPP in Türkiye. The plant produces a wide range of equipment for the project, including internal parts for the nuclear island and engine room, steam generators, tube system modules, reactor passive protection systems, pressure compensators. A total of 8 thousand tons of equipment was produced, and this figure will reach 11 thousand tons.”
The head of the Atommash plant, Maxim Zhidkov, noted that another major plant of Rosatom’s Mechanical Engineering Department, Petrozavodskmash, continues to actively produce equipment to ensure the safety of the 4th Power Unit of the Akkuyu NPP. Two hydraulic tanks were manufactured at the Petrozavodskmash plant for the passive core flooding system, which will ensure the safety of the reactor in the event of a possible emergency. These tanks store boric acid solution heated to a temperature of about 60 degrees Celsius. If the pressure in the primary circuit drops below a critical level, this liquid is automatically injected into the reactor, ensuring safe cooling of the reactor core. The passive core flooding system of a power unit consists of a total of eight hydraulic tanks, each with a volume of 120 cubic meters.
