Inner containment construction set to begin for Leningrad’s seventh unit

Pre-assembly and welding of the first tier of the inner containment has been taking place over the past few weeks next to the reactor building site and Rosenergoatom - part of Rosatom - said it will soon be ready for installation.

It is planned to begin the work on installing the first tier - to be followed by concreting and subsequent tiers of the inner containment building - during September, with the entire process expected to last for two and a half years with the entire structure due to be completed, with dome, in 2028.

Evgeny Milushkin from Leningrad NPP-2 said the inner containment would comprise a "concrete structure more than a metre thick, reinforced for strength with steel … the inner protective shell will prevent radioactive substances and ionising radiation from leaving the reactor building. This means that the personnel of the nuclear power plant, the population living next to it and the environment will be safe".

There will also be a second, external containment building, which will "protect the reactor, steam generators and other important equipment from extreme external natural and man-made influences" including hurricanes, plane crashes or earthquakes.

Background

The Leningrad nuclear power plant is one of the largest in Russia, with an installed capacity of 4400 MWe, and provides more than 55% of the electricity demand of St Petersburg and the Leningrad region, or 30% of all the electricity in northwest Russia.

Leningrad 1 shut down in 2018 after 45 years of operation. Leningrad 2, also a 1000 MWe RBMK unit, started up in 1975 and was permanently shut down in November 2020. As the first two of the plant's four RBMK-1000 units shut down, new VVER-1200 units started at the neighbouring Leningrad II plant. The 60-year service life of these fifth and sixth units (also known as Leningrad II-1 and Leningrad II-2) secures power supply until the 2080s. Units 7 and 8 (also known as Leningrad II-3 and Leningrad II-4) will replace units 3 and 4 as they are shut in the coming years.

The pouring of the first concrete for unit 7 in March 2024 marked the start of the main phase of construction of the new power unit, which is expected to generate power for 60 years, with the possibility of a 20-year extension.