A support truss – one of the main elements of the reactor shaft was installed in the reactor building of Leningrad NPP unit 7 (also known as Leningrad-II unit 3). The operation was completed three days ahead of schedule. Specialists will now concrete the internal cavities of the ring-shaped metal structure with special serpentinite concrete. It will provide radiation and thermal protection for the reactor shaft.
“It is important not only to fill the truss with concrete, but also to ensure proper care of it to gain the required strength,” said Konstantin Khudyakov, director of the programme for Leningrad NPP facilities at Titan-2 (general contractor). “After the mixture has hardened, we will definitely confirm its quality using non-destructive testing methods. We will also check the position of the support truss before and after concreting. The elevations, the alignment of the truss with the shaft and the position along the main axes should remain the same. This will allow the truss to operate normally under serious loads (temperature, radiation and weight). We plan to complete all work on the support truss in July.”
Evgeny Milushkin, Deputy Director of the Leningrad NPP and Head of the Capital Construction Department at Leningrad-II explained that the operation performed is preparation for installation of the reactor vessel.
“The next stage will install another truss, this time a substantial one. It will protect the reactor from lateral displacements during operation. Double fastening of the most important equipment of the power unit will ensure reliable and safe operation in absolutely all modes, no matter what happens inside or outside the building. For the entire design life, which is at least 60 years, the reactor weighing more than 300 tonnes will remain in its proper place.”
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 the RBMK-1000 reactors at units 1&2, which were decommissioned in 2018 and 2020. New VVER-1200 units (7&8), now under construction, will replace units 3&4. Unit 7 is scheduled to begin operation in 2030 and unit 8 in 2032.
