Another milestone achieved in construction of the innovative BREST-OD-300 fast neutron reactor at the site of the Siberian Chemical Combine, a subsidiary of Rosatom’s TVEL Fuel Company, as the pouring of the nuclear island’s foundation slab has been completed. The BREST-OD-300 foundation slab, 90 x 82 meters and 2.5 meters thick, consists of nine separate units. The works have been carried out by the general contractor Titan-2, the scientific support is provided by the Research Institute of Reinforced Concrete Structures, based in Saint-Petersburg.Almost 19 thousand cubic meters of concrete, 4.3 thousand tons of reinforcement were laid in the foundation slab of the nuclear island - this volume would be enough for construction of two eight-story buildings. The builders have been working around the clock.The plate strength for BREST-OD-300 is significantly higher than for standard reactors. The foundation concreting had been preceded by the profound research, the properties of concrete had been thoroughly studied, in order to ensure the required quality. In May 2021, before the first concrete was poured, a model of the foundation slab had been created, so that the experts could test the quality of joints between the blocks. The foundation slab is based 6,4 meters underground. Currently, the builders are working on construction of the boundary walls.