The extension period will start on January 3, Nuclearelectrica in a statement filed with the Bucharest Stock Exchange, BVB, late on Wednesday.
In August, Ghita was appointed CEO for a four-month period, replacing Daniela Lulache, who had been Nuclearelectrica CEO since 2013.
Since June, Ghita is also president of the administration council of Romania's National Uranium Company (CNU).
Nuclearelectrica's net profit leapt to 225.3 million lei ($56.4 million/48.4 million euro) in the first nine months of 2017, driven by increased electricity output and sales.
The Cernavoda power plant, located in southeastern Romania, has two units of 700 megawatts each, which cover roughly a fifth of the country's electricity needs.
Nuclearelectrica shares traded 0.56% lower at 7.16 lei by 1016 CET on Thursday on the BVB.
Romania's energy ministry owns a 82.49% stake in Nuclearelectrica.
(1 euro =4.6276 Romanian lei)