BREST. The third and final section of the containment structure was installed in the reactor pit at the construction site of the BREST-OD-300 lead-cooled fast reactor. Together with the rigging equipment, its weight reaches 164 tonnes. The reactor containment structure consists of three sections, being 429 tonnes heavy and 17 meters high when assembled. Having connected the third and second tiers of the containment structure, the workers will proceed with installing pipes for the cooling and drying system and an intermediate shell. The cavity of the containment structure will then be filled with heat-resistant concrete. The structure is an outer part of the reactor plant. Its heat-insulating layer of concrete serves as an additional protection barrier beyond the boundary of the coolant circuit.