Cernavodă Unit 1 drops off Romania's grid as Unit 2 begins its restart

Romania's Cernavodă nuclear plant had both reactors off the grid again on the evening of November 9, 2026, three days after Unit 1 returned from a shutdown tied to the Danube's water level. Nuclearelectrica says Unit 1 was disconnected from the National Energy System that evening after a malfunction in the conventional part of the unit, with no impact on nuclear safety, personnel or the environment. Repair work is under way, and the root cause will be set out in a later report.

The timing was awkward. That morning, Nuclearelectrica had announced the start of Unit 2's reconnection procedures once the water level needed for a safe restart was reached, with synchronization expected November 10 and nominal power November 11. Chief executive Mihai Gioară said the plant would run both units from November 11, helping to supply about 20% of Romania's energy needs. By evening, the unit that had been running was the one waiting to reconnect; the later release says teams are carrying out reconnection procedures for both units and gives no new dates.

Both units had been held in a safe shutdown, which the company said on October 11 would last until the Danube allowed a safe restart. Unit 1's reconnection began November 4, when the company said Unit 2 would need a sustained rise in the river, because running Unit 1 draws down the intake basin. It was synchronized November 6 and was at 50% of nominal power during the prime minister's visit on November 7.

Nuclearelectrica is replacing the plant's Technical Director effective December 1, 2026, and will evaluate all maintenance activities against the plant's procedures and international reference standards. Gioară said that in 2026, besides the weather, the plant "faced temporary, unplanned outages caused by malfunctions in the auxiliary technical systems." He added that "the frequency of these outages fell below the standards of excellence we have set for ourselves." The remediation plan, he said, includes an accelerated review of maintenance procedures.