Certification of nuclear power plants as supporting service providers

The stepwise creation of power grid requirements put on the operation of nuclear power plants in the control modes is described. The certification criteria and the feasibility of meeting them by Czech VVER type NPPs are discussed. The power plants include Dukovany (4 units 440 MW each), which is fully operable, and Temelin (2 units 1000 MW each), which is in the starting stage of operation. The basic changes in the Dukovany plant control systems that had to be made before launching the control modes are described. The results of the certification measurements of the supporting services and of the island mode operation are shown for the two nuclear power plants. (author)