VVER-1200

A flat blank made of pearlitic steel is heated in a furnace at 1000 °C and then placed under a press with a maximum force of 15 000 tf, which forms the bottom of the blank. The double-acting hydraulic sheet punching press is unique and the only equipment in Russia that can stamp bottoms from blanks up to 380 mm thick.

Assembly and joining of two half-vessels and making of the closing weld are one of the key stages of the reactor vessel manufacturing cycle. Welding and overlay welding are carried out automatically using special equipment. Heat treatment of blanks is carried out in gas-flame chamber furnaces to obtain the highest performance characteristics of products.

The machining process includes the manufacture of threaded holes for the studs of the reactor main joint, as well as general work on the finishing of surfaces, welds, nozzles, drilling holes in the internals

During the entire reactor manufacturing process, most of the time is devoted to control tests. Radiographic test equipment is used to detect defects in thick-walled products. The control of welded joints is ensured by means of liquid penetrant and ultrasonic test procedures. In a specially equipped underground stand - a caisson - hydraulic tests are carried out. A pressure of 25.7 MPa (262 atm) is injected into the vessel, in ten minutes the pressure should not fall below 24.5 MPa (250 atm).

In total, hundreds operations are carried out after docking of the reactor half-vessels. Particular attention is paid to nondestructive testing methods.