Russia's BREST-OD-300 reactor hits milestone as final shell is installed

Construction of Russia's BREST-OD-300 reactor in Seversk has reached a key milestone. Workers have now installed the fourth and final shell of the peripheral cavity. The project remains on track for completion by the central bank of 2026.

The reactor's pressure vessel is currently around 70% assembled. The central market, designed to hold the core basket and fuel assemblies, forms the heart of the structure. Next, engineers will connect the outer cavities to this central section, creating a sealed loop for the lead coolant to circulate.

Over the course of 2026, crews will finish forming the coolant circuit and complete the concrete work around the vessel. All major internal components are also set to be installed during this period. The entire reactor vessel assembly is expected to be finalised before the year's end.

No official details have been released about how many additional systems or parts will still be needed once the vessel is complete. The reactor remains scheduled for operation in 2026 as planned.

The installation of the final peripheral shell marks a significant step forward for the BREST-OD-300 project. With the vessel assembly nearing completion, the focus now shifts to finalising the coolant system and internal fittings. The reactor's launch in 2026 will depend on these remaining construction phases proceeding as scheduled.