Wedoany.com Report-Oct. 21, Construction has started on the outer containment building for the third new unit at the Leningrad nuclear power plant, marking the seventh unit at the site. This development is part of the Leningrad II phase, which includes two VVER-1200 units commissioned in 2018 and 2021, with the third and fourth units currently under construction. Together, these new units will replace the four RBMK-1000 units from the original 1970s Leningrad plant.

Work is taking place on both containment buildings

The outer containment building is being constructed in successive tiers of a reinforced steel “cage,” which will then be filled with concrete. Once complete, it will stand 70 metres high, measure 52 metres in diameter, and have walls 80 centimetres thick. Containment buildings are key safety features; the VVER-1200 units include both inner and outer containment as part of a double-layer protection system, with the outer containment designed to withstand external hazards such as earthquakes or aircraft impacts.

Leningrad NPP-2’s Evgeny Milushkin said: "The outer containment shell will be constructed in tiers. We plan to have the first one ready as early as November. The structure, approximately four metres high, will require over 200 tonnes of steel reinforcement and nearly 600 cubic metres of concrete. Early next year, the shell will grow another four metres. The entire outer containment shell will be ready in 2028."

Construction of the inner containment is progressing simultaneously. Last month, the lower tier of the inner containment building, with a diameter of 44 metres, a height of 10 metres, and weighing 227 tonnes, was lowered into place. Work is also ongoing on the reactor building and the core catcher. Rosatom reports that more than 1,000 personnel are involved in building both the third and fourth new units. The units are scheduled to enter service in 2030 and 2032.

The Leningrad nuclear power plant is one of Russia’s largest, with an installed capacity of 4,400 MWe. It supplies more than 55% of St Petersburg and the Leningrad region’s electricity needs, equivalent to 30% of northwest Russia’s total power. Leningrad 1 was shut down in 2018 after 45 years of operation, while Leningrad 2, a 1,000 MWe RBMK unit, started in 1975 and was permanently shut in November 2020. As the first two RBMK units were decommissioned, the new VVER-1200 units at Leningrad II began operation.

The fifth and sixth units (Leningrad II-1 and II-2) have a planned service life of 60 years, securing power supply until the 2080s. Units seven and eight (Leningrad II-3 and II-4) will replace the remaining RBMK units in the coming years. The first concrete for unit seven was poured in March 2024, marking the start of the main construction phase. The new units are designed to operate for 60 years, with the potential for a 20-year extension, ensuring a long-term and stable energy supply for the region.