Concreting has been completed for the first of two sections of the foundation slab at the control building for unit 7 of Russia’s Leningrad NPP. The control building is one of the seven facilities that are part of the nuclear island.
Currently Leningrad NPP has four units in operation – units 3&4 with Soviet RBMK-1000 reactors, as well units 5&6 with new VVER-1200 units (also known as Leningrad-II 1&2). Units 5&6 replaced units 1&2, RBMKs which were decommissioned in 2018 and 2020. New VVER-1200 units (7&8) will replace units 3&4. They are scheduled to be put into commercial operation in 2030 and 2032. Currently, at the construction site of units 7&8 About 500 people are involved in construction and installation at 18 sites.
In total, workers will have to build a foundation slab with an area of about 2,570 square metres. To do this, they will need almost 4,000 cubic metres of highly durable concrete.
“We used 37 mixers to deliver concrete. Concrete was laid using four automobile concrete pumps with a concrete mix supply rate of 100-120 cubic metres per hour,” said Konstantin Khudyakov, Director of the Leningrad Facility Programme at general contractor TITAN-2. “This allowed us to complete the concreting of the first section in less than 24 hours. For this we needed 2,200 cubic metres of concrete. After reinforcement and concreting of the second section and the foundation slab reaching its design strength, work on the construction of reinforced concrete walls will begin at the control building,”
“The control building is one of the most important objects at a nuclear power plant,” explained Deputy Director for Capital Construction and Head of the Capital Construction Department of Leningrad NPP-II, Evgeniy Milushkin. It will house monitoring, protection and control systems for the power unit, automated process control systems and two brain centres – the unit and reserve control centres. And right now, builders are laying the foundation for their reliable and efficient operation and for the safe work of operating personnel.”
From the unit control centre, operating personnel, working around the clock, will control the technological processes at the unit in all operating modes, monitor the condition of its systems, and adjust the parameters of the reactor, turbine and other main equipment to ensure safe, reliable and efficient operation. The reserve control centre will be needed to shut down and transfer the power unit to a safe state, as well as to carry out long-term heat removal from the reactor core if it is impossible to perform these operations from the unit control centre.
Although the control building will not house large-sized and heavy equipment, and during operation there will be no sources of ionising radiation, its foundation and building structures are subject to the same stringent requirements as the reactor building. It must be earthquake-resistant and able to withstand the most severe external loads. Even before the start of concreting the first section, complex reinforcement was carried out at the site for 100 days. As a result, the builders placed more than 700 tonnes of reinforcement into the building’s foundation slab. In terms of length, this amounted to 100 kilometres.
