11.06.2022
The most significant milestone of the year has been implemented at Kursk NPP-2 on the eve of Russia Day - the VVER TOI reactor vessel has been installed in design position at Power Unit 1. This is the most important equipment for the NPP primary circuit. At the stage of operation, nuclear fuel is loaded inside the reactor vessel where a controllable nuclear reaction takes place with emittance of large amount of heat.
“We have fulfilled another task of the state, three weeks ahead of schedule - we have assembled the reactor vessel. It was delivered to the site back in September 2021. Since then, a huge amount of work has been performed for the preparation of the transportation and the process flow sheet for the vessel installation. The placement of the reactor vessel in the design position launches the active phase of the reactor equipment installation. This event marks the countdown of the start of commissioning works at the NPP”, said Andrey Osharin, First Deputy Director for Contraction of New Units of Kursk NPP, speaking about the importance of this event.
The installation of the “nuclear heart” in the design position was performed in several stages. At first, a Liebherr caterpillar crane brought the reactor vessel to the transportation portal of the power unit and loaded it on a special transportation trolley. Then the equipment was taken to the central hall of the reactor compartment, and, with a polar crane, was installed on the support ring in the reactor pit at the elevation of 11.3 meters. The maximal permissible deviation during the installation operation was one tenth of a millimeter - the thickness of a shaving razor.
The VVER-TOI reactor vessel was designed and manufactured at Russian enterprises - the companies of Rosatom State Corporation.
“The VVER-TOI reactor vessel has its own specific features. It differs from VVER-1200 not only in a more symmetrical location of nozzles, but also in fewer welding joints - four instead of six because there are no welding joints in the core area. This improves the operational properties of the vessel taking into account the fact that radiation has a negative effect on the structure of welding joints. This upgrading will make it possible to extend the vessel service life after sixty years - twice for twenty years”, said Alexey Volnov, Chief Engineer of Kursk NPP.
“The installation of the reactor vessel is the result of long-time work of a big team of like-minded professionals. After this stage, the construction project has transferred from the construction active phase to thermal installation phase. Having implemented the key task of 2022, we will continue to prepare for welding of the reactor coolant pipelines whose installation will commence soon”, said Oleg Shperle, Vice President - Director of Kursk NPP Construction Project.
The VVER-TOI reactor vessel weighs 340 tons, its length is 13 meters, it is manufactured from nickel-free steel which does not change its properties under the influence of radiation and high temperature. The reactor vessel can withstand the pressure of 250 atmospheres, which is 1.4 higher than the operational pressure. This can be compared to the ocean pressure at the depth of 2.5 km.
The equipment was manufactured at Atommash plant in Volgodonsk.
The construction of Power Units 1 and 2 of Kursk NPP-2 is performed within the framework of federal project “Designing and construction of reference power units of nuclear power plants” of comprehensive program “Development of research and technology in the field of use of atomic energy in the Russian Federation up to 2024”.
