On May 16, 1975, the Commission on preparation to and commissioning of the 1^st Power Unit was established by an order of the ChNPP Director. From the beginning of October 1975 the first fuel assemblies started to arrive to a fresh fuel warehouse. Twenty-four hour work was organized due to delay from the planned terms in critical milestones of the Unit commissioning schedule. The Director’s order on organization of continuous works regarding the 1^st Power Unit graphite stack was issued on November 25, 1975. Regular dosimetric control within the areas adjacent to the ChNPP was established on May 15, 1976, in accordance with the detailed design and SES requirements. In October 1976 filling of the cooling pond was started. At the same year a working area of “Lvovenergoremont” enterprise was arranged at the ChNPP to perform adjustments, as well as to provide repair of the Turbine Hall’s power equipment.

At the beginning of May 1977 a team of assemblers, builders, operating personnel of the ChNPP proceeded with pre-commissioning activities at the 1^st Power Unit. From July 8, 1977, a contamination controlled area (CCA) was arranged due to commencement of works on fuel charging. The first FA was charged on the 1^st of August at 20.10. Finally, on August 14 at 11.55 a.m. the full charging of fuel was completed. On September 18, 1977, at 16.17 the reactor power rise commenced. On September 26 at 20.19 the 1^st Unit turbine generator No.2 was connected to the grid. Turbine generator No.1 was connected to the grid on the 2^nd of November. On December 14, 1977, the ChNPP 1^st Power Unit Commissioning Certificate was signed. On May 24, 1978, the first Power Unit was brought to 1,000 MW capacity.