Romania’s second nuclear reactor at the Cernavoda power plant on the river Danube has been reconnected to the national power grid, its owners have confirmed.
The reactor was taken offline on Saturday, owner Nuclearelectrica said.
It said in a statement the halt was triggered by a “software-related” matter.
Nuclearelectrica, which has two 706 megawatt reactors at Cernavoda, said the glitch and consequent works to fix the software had not implied any risk to the nuclear safety of the reactor.
The statement said: “Nuclearelectrica SA announces that Unit 2 of the Cernavoda NPP has automatically disconnected from the National Power System on the morning of 22 July 2017, due to the re-emergence of a transient in the classical part of the power plant.
“Unit 2 was reconnected to the NPS on the evening of July 21, 2017 after an automatic disconnection caused also by a transient in the classic part of the power plant on July 20, 2017.
“Cernavoda NPP specialists investigate, with the support of its manufacturer, the software that generates the transient to eliminate its occurrence and, implicitly, the disconnection from the NPS.
“The disconnection of Unit 2 from the NPS is explained by the fact that the nuclear reactors are programmed by the project to automatically disconnect even in the case of a soft transition from the classical part of the boiler.
“After identifying the cause and remedying the situation, Unit 2 of the Cernavoda NPP will be reconnected to the NPS.
“The appearance of some transients on the classical part of the boiler does not imply any impact on nuclear reactor safety, operating personnel, population and the environment, and the plant’s systems operate according to the project, which explains the automatic disconnection of the NPS reactor.”