The melt localisation device (ULR – Ustroistvo Lokalizatsii Rasplava) for unit 8 of the Leningrad NPP (also known as Leningrad-II unit 4) has been delivered to the pier of the city of Sosnovy Bor. The equipment, weighing more than 730 tonnes took 16 days to make the 2,000-kilometre journey from Tyazhmash in Syzran, Samara Region. Most of the trip was by water including the Volga, White, Onega and Ladoga lakes, the Neva and the Gulf of Finland.
Currently, the equipment is being prepared for transportation to the construction site. After incoming control, the melt trap will be installed in the reactor shaft. At the next stages, specialists will sequentially install the remaining elements of the device, including blocks containing sacrificial material.
The melt trap, a unique Russian technology, is one of the passive safety systems of the plant with Generation 3+ VVER-1200 reactors. In the event of a hypothetical accident resulting in melting of the core, the melt trap filled with a special sacrificial material will reliably hold the entire highly radioactive fuel melt until it completely cools and crystallises, eliminating its contact with the environment.
“We set ourselves the task of installing the melt trap in the reactor shaft two months ahead of schedule,” said Vladimir Pereguda, Director of the Leningrad NPP. “This will make it possible to intensify work at this facility and carefully prepare for the most important event in any NPP construction — installation of the reactor vessel. According to the schedule, it should take place in 2029.”
The melt trap for Leningrad 7 was delivered in September 2025. The melt trap housing was installed in October and the melt trap itself in June.
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), now under construction, will replace units 3&4.
