The Leningrad NPP: cooling tower hydraulic tests have commenced at the innovative VVER-1200 2nd power block

The construction team at the Leningrad NPP has started hydraulic tests of the 170-meter high cooling tower erected for the VVER-1200 2nd power block. 35,000 cubic meters of water will be placed in its basin to verify the endurance and the leak integrity of its foundation and end.

‘The contractors will fill in the basin up to the designed mark of +1.85 meters. By the end of December, we will be tracking the basin walls leak integrity and the level of water in it. These tests are to verify the water impermeability of the constructions. Reliable cooling tower operation relies on their quality. When in use, the cooling tower will facilitate heat removal from the turbine condenser, a critical piece of equipment’, Andrey Rozhkov, the deputy head of support systems, said.

The end reinforced-concrete slab and the basin enclosure are made of hydraulic content. It is based on Portland cement boasting high water impermeability, freezing tolerance, compressive and tensile strength. Following the hydraulic tests, the water will be pumped off from the cooling tower, and the end and the basin enclosure’s inner and outer surface will be covered with a special waterproofing layer.

By the end of 2019, the hydraulic tests will also run at the 1st and the 2nd circuits of the reactor facility. These will be followed by the equipment hot trial, a major step before the physical launch of the new power block, which is scheduled for Q2 2020.


Evaporative cooling towers are elements of a circulation water supply system. They are used to remove heat from turbine condensers. A cooling tower is a giant reinforced concrete heat-exchange unit. As with any high tower, it has thrust force of an upward air current. Water is piped from the turbine condensers into the cooling tower, sprayed at a height of 13 meters and then flows down. Following that, the cooled water gets into the basin and piped again to cool down the turbine condensers. There is no reason to be scared of cooling towers. What they emit is regular water steam that does not contain any radioactive materials since it does not come into contact with the primary circuit’s radioactive water. There are three cooling towers designed for the Leningrad NPP: two of them are 150 meters high for the VVER-1200 1st power block and one is 170 meters high for the 2nd power block. The cooling towers are designed for nuclear power plants construction in accordance with Article 60 of the Water Code of the Russian Federation. The amendments made on July 14, 2008 state that designing technical water supply once-through systems is prohibited.

The Leningrad NPP is the country’s first plant with RBMK-1000 reactors (uranium-graphite circuit-type reactor running on thermal neutrons). The decision that marked its construction was taken in September 1966 by a resolution of the Central Committee of the Communist Party of the USSR and the Council of Ministers No. 800-252. According to that document, the Leningrad NPP was supposed to become a core in a network of nuclear power plants with RBMK-1000 reactors that were supposed to produce a substantial share of electric power. The construction of the Leningrad NPP was going well, and by 1973 the first power block was fully erected. On December 23, 1973, following stable 72-hours’ operation at the capacity of 150 megawatt, the State Commission signed the acceptance certificate stating that the first power block of the Leningrad nuclear power plant is commissioned for pilot production.rship

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