Atommash, the Volgodonsk branch of AEM-Technologies JSC (part of Rosatom mechanical engineering division Atomenergomash) on 8 April shipped the first VVER-TOI nuclear reactor pressure vessel for the unit 1 of Russia’s Kursk-II NPP. VVER-TOI is a development by OKB Gidroress based on the technical solutions for VVER-1200 reactor plants. VVER-TOI reactors have increased power, improved technical and economic indicators and increased resistance to extreme external influences and natural disasters.
Andrey Nikipelov, General Director of JSC Atomenergomash, noted: “The main difference between VVER-TOI and previous projects with VVER-1200 reactors is its “typification” through the use of information technologies: regardless of where the NPP will be built, developers and equipment manufacturers will be able to use a single information base with existing proven solutions and adapt them to a specific project."
The new reactor is made of nickel-free steel. The technology provides for four welds instead of six (as in the VVER-1200 reactor vessel). The decrease in the number of welded joints in the zone of increased radiation exposure improves the operational characteristics of the reactor vessel. For automatic submerged-arc welding, welding materials were used that were not previously employed at Atommash. The RPV weighs about 340 tons.
During manufacture of the VVER-TOI reactor, plant specialists carried out a full range of product tests, including hydraulic tests of the vessel with a standard upper block cover at a pressure of 24.5 MPa (250 atmospheres), which is 1.4 times above the operating pressure. The final stage in the manufacture of the product was the control assembly with internals. A shaft, a baffle, and a block of protective pipes were installed in the reactor vessel. The plant's specialists, together with the customer's representatives, performed the necessary control operations. As a result, all geometric parameters, alignment of elements were checked and the quality of the manufactured product was confirmed.
“Creation of any new high-tech product, let alone a new generation reactor, is always a non-trivial task. On the one hand, in the case of VVER-TOI and equipment for it, the basic design solutions are already well known and have been worked out by us in practice, in production,” said Igor Kotov, General Director of AEM-Technologies. “On the other hand, in nuclear engineering, any changes in the manufacture of a new product entail a whole series of solutions for adapting the technological process. And these are rather lengthy and complex processes. A lot depends on the effectiveness of this task.
The VVER-TOI will be delivered by road to the special berth of the Tsimlyansk reservoir, then by river along the Don and Volga to the pier in Voronezh. There the product will be reloaded onto vehicles and delivered to Kurchatov. The cargo will travel 1,500 km by water, and when transported by road train, the road route will be 300 km, including crossing nine bridges.
Kursk-II is a replacement station for the current Kursk nuclear plant. Commissioning of the first two units with the new design VVER-TOI reactors will be synchronised with the decommissioning of the RBMK reactors at Kursk 1&2 of the operating plant.