Romania Warns of Potential Shutdown of Sole Remaining Nuclear Reactor

Cernavodă Unit 2 Might Shut Down Thursday as Danube’s Drop Affects Power Supply

Romania’s sole active nuclear reactor may halt operations on Thursday morning due to a severe hydrological drought lowering the Danube below necessary levels for consistent cooling-water supply. This situation adds pressure to Romania’s power system after the other reactor was shut down in July.

Nuclearelectrica, the state-owned operator, mentioned a potential controlled shutdown of Cernavodă Unit 2 on 13 August, based on river forecasts, operating conditions, and the Danube’s declining water levels.

The company’s latest update from 11 August didn’t confirm the closure had commenced. Nuclearelectrica stated it would release another announcement if a shutdown became imminent.

Safety Decision and Supply Impact

The potential shutdown is a safety measure to maintain the reactor’s nuclear safety margins. There’s no sign of any radiological incident or facility malfunction.

However, its effect on power supplies could be significant. Cernavodă’s two reactors typically generate around a fifth of Romania’s electricity. Unit 1 has been controlled shutdown since 28 July due to the exceptionally low river level, leaving Unit 2 as the lone power source.

Nuclearelectrica has secured force-majeure certificates for electricity supply contracts. The drought has hindered fulfilling contractual obligations since 27 July. These certificates don’t directly remove electricity from the grid but acknowledge the hydrological crisis affecting the producer’s contractual delivery capabilities.

Romania declared a state of alert in the energy sector on 31 July. Authorities have urged residents and public institutions to voluntarily reduce consumption during evening peaks when solar generation falls, yet demand remains high.

Emergency Works Provided Limited Relief

Romanian authorities dredged parts of the river and submerged four rock-filled barges near the Bala Canal to divert more water towards Cernavodă, temporarily raising the local water level and allowing Unit 2 to operate.

Nonetheless, the benefit wasn’t expected to last. Earlier this month, the Danube’s flow into Romania decreased to about 1,400 cubic meters per second, under one-third of the seasonal average, as per reports on the emergency works.

The renewed shutdown warning indicates these measures may have only delayed, not eliminated, the risk. Restarting either reactor will depend on water conditions and confirming operating requirements can be safely met.

A Regional Grid Challenge

Romania can compensate through gas-fired generation, renewables, storage, and imports. However, neighboring electricity systems also face drought, heat, and reduced hydroelectric or nuclear output, making cross-border capacity critical during evening demand peaks.

This situation underscores the need for the EU’s proposed overhaul of European power networks. Stronger interconnections and faster access to flexible generation could prevent a national production loss from escalating into a wider supply emergency.

Authorities must ensure fair conservation burden distribution. Hospitals, care facilities, and those dependent on electrically powered medical equipment can’t reduce demand as easily as others. Clear public information, targeted assistance, and protection against sudden price hikes are vital alongside technical grid management.

Understanding the Cernavodă Shutdown Alert

Nuclearelectrica, Romania’s state-owned nuclear operator, warned on 11 August 2026 that Cernavodă Unit 2 might shut down on 13 August morning due to falling Danube levels threatening cooling-water supply necessary for safe operation. Unit 1 has been offline since 28 July, with no nuclear accident or radiological danger reported.

Key Facts

Plant: Cernavodă Nuclear Power Plant, Romania
Operator: SN Nuclearelectrica SA
Affected Reactor: Cernavodă Unit 2
Potential Shutdown: Morning of 13 August 2026
Immediate Cause: Exceptionally low Danube water levels during severe hydrological drought
Current Status: Shutdown possible but not confirmed when the warning was issued
Safety Status: No radiological incident or reactor malfunction reported
National Importance: Cernavodă’s reactors usually provide about 20% of Romania’s electricity