The initial operation of the fifth unit was characterized by an increased number of transitional regimes, the number of which did not exceed the design values. No effect of the considerable number of power variations on the working efficiency of the fuel elements was observed. An analysis of the primary circuit coolant activity with respect to fission products shows that operation of the fifth unit is characterized by a low degree of depressurization of the fuel element cans. The number of fuel elements with microdefects is significantly lower than the limiting value, which confirms the high reliability of the fuel elements. After attaining nominal power level, no marked depressurization of the fuel elements develops.

Experience in the operation of NPP with VVÉR reactors from 1964 confirms that the steps taken to ensure their safety were in the right direction. The escape of radioactivity from NPP and the radiation doses in their rooms are significantly below admissible values. The operation of NPP with VVÉR reactors has not affected the radioactivity levels measured in their vicinity. The only cases of leaks in the primary loop were compensated by the reserve water supply at a pressure close to nominal. The extensive measures to ensure the safety of NPP with VVÉR reactors under construction and those being designed at the present time are in line with their increasing use in the USSR power system.