Concrete preparation for the foundation of VVER-1200 reactor at unit 8 of the Leningrad NPP lasted about two months and was completed two and a half months ahead of schedule, according to general contractor TITAN-2. In June, the construction of the pit for the building of the unit 8 reactor was completed two weeks ahead of schedule.
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 with RBMK-1000 reactors, 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.
“The technology for constructing the “concrete footing” included performing reservoir drainage from several layers – lean concrete, sand, porous concrete. Then the reservoir drainage was cut off with a special film before the concrete preparation.” said Konstantin Khudyakov, Director for the Leningrad NPP at TITAN-2. “Concrete of strength class B35 was used in the work – it is considered a heavy material with high density and is used for monolithic structures that experience significant loads.”
The next stage of construction will be work on lightning protection and waterproofing, which will last until the end of August. Next, the screed device will be installed.
“The completed work will allow specialists to begin reinforcing the foundation slab. Reinforcement with steel components creates a kind of frame and makes the foundation extremely strong,” said Evgeniy Milushkin, Deputy Director for Capital Construction and Head of the Capital Construction Department at Leningrad-II. “Reinforcement work is determined by an additional schedule and will begin in October of this year. Thus, we are preparing for the first key operation – concreting the foundation layer of the reactor building.”
The work schedule provides for pouring first concrete for the foundation of the reactor building unit 8 in 2025. Over the next five years, builders will have to erect a building almost 70 metres high and install the reactor, steam generators, the main circulation pipeline, and melt trap. First concrete for unit 7 was poured in March.
