AtomEnergoMash made its first reactor vessel bottom for VVER-TOI, an upgraded version of the VVER-1200 reactor.
The lowest part of the reactor vessel to be installed at Kursk-II Unit 1 will be manufactured at Atommash, AEM’s subsidiary based in Volgodonsk (Russia).
The manufacturing process was divided into two stages. First, a tube-shaped forged steel blank was flattened to obtain a steel plate. “This is the only way to make a seamless steel plate of the required dimensions,” a representative of AEM explained.
The resulting 300 mm thick plate weighed 64 metric tons. At the second stage, the plate was heated at 1,070°C for six hours. Then, the red-hot plate was put into a press with a special die set. The required shape was obtained by stamping the plate with a force of 12,000 metric tons.
VVER-TOI is an evolution of the VVER reactor family (TOI stands for ‘standardized, optimized and automated’). VVER-TOI has a somewhat wider vessel than the VVER-1200. This critical component has fewer weld seams and, consequently, a longer service life. The VVER-TOI version also has more steam generators per meter.
It is fitted with a new main centrifugal pump cooled and lubricated with water. This solution helps minimize risks associated with the use of inflammable lubricants. The first unit with a VVER-TOI reactor will be built at Kursk-II to replace one of the units at the operating Kursk-I nuclear power plant.