While the full review of the project is still ongoing, construction of the Unit 5 reactor building foundation slab has begun with due consideration for business continuity. 

The first segment of the foundation slab is a circular concrete structure, a concrete ring, more than 50 metres in diameter, with a radial width of 13 metres and a height of nearly 3 metres.  Due to its size, it cannot be constructed as a single structure, so it is being built in several bays along the circumference. The concreting for the first such circular bay began on the evening of 30 July 2026. Prior to this, 270 tonnes of reinforcing steel were installed over a period of two months. From Thursday evening, the machinery operated and specialists worked continuously for twelve hours in the excavation pit and in the concrete batching facility: 776 cubic metres of C35/45-class basalt concrete mix were poured in 12 hours. 

The installation and preparatory works for the first concrete pouring phase had been completed in advance. The supporting levels were constructed, on which the reinforcement was installed. In recent months, the so-called embedded and concealed elements have been put in place, i.e. stainless steel pipelines, geodetic measuring points and steel support elements that provide the mounting surfaces for future equipment, pipelines and other elements. 

The reactor is the key component of any nuclear power plant, therefore the building that houses it is of paramount importance from both engineering and nuclear safety perspectives. The foundation of the reactor building is being constructed in several phases and the works are coordinated with the foundation activities of other buildings on the common foundation slab.