Romania's Cernavoda nuclear power plant has disconnected Unit 1 from the national grid again, only days after the reactor returned to service following a shutdown of almost three months caused by low water levels in the Danube. Operator Nuclearelectrica said the unit was taken offline on the evening of Monday 9 November 2026 after a malfunction in the conventional, non-nuclear part of the plant.

The company said in a statement filed with the Bucharest Stock Exchange on Monday evening that the disconnection was carried out in accordance with operating procedures and had no impact on nuclear safety, personnel or the environment. Specialists at the plant are working to resolve the fault, with restarting Unit 1 and reconnecting it to the National Energy System as the priority. The root cause will be analysed in detail and presented in a later report.

Nuclearelectrica also announced a change at the top of the plant's technical management. The technical director of the Cernavoda plant will be replaced with effect from 1 December, with the company citing the responsibility of technical management for ensuring the availability of the equipment required to operate the reactors. Chief executive Mihai Gioara said the company would also put in place an operational remediation plan, including an accelerated review of maintenance procedures.

A troubled return after the summer shutdown

The latest fault is a setback for a plant that had only just come back to life. Unit 1 was shut down in a controlled manner on 28 July 2026, and Unit 2 followed on 13 August, after a sharp fall in Danube water levels during the summer drought left the plant without enough cooling water. Both reactors had been offline since 14 August.

Restart procedures for Unit 1 began on 4 November, once the Danube level had recovered enough to meet the minimum safety conditions. The unit was resynchronised with the grid on the afternoon of Friday 6 November and reached nominal power on Sunday 8 November. Prime Minister Luca Niculescu visited the plant on Saturday 7 November and said the three-month shutdown was estimated to have caused losses of around 200 million euros.

Cernavoda is Romania's only nuclear power plant and meets around 20 percent of the country's electricity needs. Its two units each have an installed capacity of about 700 MW: Unit 1 has been in operation since 1996 and Unit 2 since 2007. Nuclearelectrica shareholders recently approved an 800 million euro loan from the European Investment Bank to finance the refurbishment of Unit 1.

Unit 2 restart expected on Tuesday

Work to bring the second reactor back is continuing in parallel. The start-up sequence for Unit 2 began at 00:42 on Monday 9 November, and the unit is expected to be synchronised with the grid on Tuesday 10 November, reaching nominal power on 11 November, according to the Ministry of Energy. Once both units are running, the plant is expected to cover about a fifth of Romania's energy needs again.

Whether Unit 1 can be restarted quickly will now be watched closely in Bucharest, after a summer in which the drought exposed how dependent Romania's nuclear output is on the Danube. For now, the operator's message is that the fault was in the conventional part of the plant, that safety was not affected, and that getting Unit 1 back on the grid is the immediate priority. SeeNews reported the disconnection and the technical director's replacement, and the Nuclearelectrica press release confirms the malfunction and the restart priority.