Romanian authorities sank four rock-laden barges into the Danube River on Thursday, racing to redirect water toward the Cernavoda nuclear plant before falling river levels force a second reactor offline.
The military blasted rock from the riverbed near the Danube’s Bala Canal earlier in the week using explosives, then loaded the debris onto four barges. Crews lowered the barges into the river to form an underwater barrier, one meant to push water into the main channel and send it downstream toward Cernavoda.
Cernavoda’s director, Romeo Urjan, told local news channel Digi24 on Thursday that the river had dropped about two centimeters, or roughly 0.7 inches, between Wednesday and Thursday alone. Without the barges, he said, the plant’s second reactor would likely need to shut down within five to six days. “If the installed barges bring surplus water… instead of five to six days, we will talk about nine to 10 days of operation from today onward,” Urjan said.
He added that any benefit from the submerged barges would take roughly a day to reach the plant, which sits about 60 kilometers, or 37 miles, downstream from the barrier site.
Cernavoda normally supplies about 20% of Romania’s electricity when both of its reactors run at full capacity. The plant draws river water to cool those reactors, which makes it directly exposed to the Danube’s falling levels. One reactor already shut down last week after an extended heatwave and thin rainfall pushed the river to record lows across the region.
A RIVER RUNNING THIN
The Danube’s flow in Romania has dropped to 1,400 cubic meters per second this week, its lowest point in decades and less than a third of the volume typical for early August. The shortfall stems from a combination of extreme heat and a prolonged dry stretch that has gripped the wider Danube basin, cutting into both hydropower generation and the cooling capacity nuclear plants depend on.
Authorities have added other emergency steps since the first reactor went offline, including dredging sections of the riverbed to keep water moving toward the plant. Acting Prime Minister Ilie Bolojan declared a nationwide state of alert in the energy sector on July 31, and he renewed his appeal to households and local governments on Thursday, asking them to cut electricity use voluntarily during peak evening hours.
Bolojan said the barge operation would likely continue through Friday. Speaking after a government meeting, he said the goal of the work carried out so far is to maintain enough flow toward Cernavoda so the second reactor can keep running “at maximum capacity,” even as forecasts point to continued low levels on the Danube.
He also acknowledged the risk facing the country if the plant goes fully offline. Romania’s ability to cover any shortfall would depend partly on importing power from neighboring countries during peak evening demand, Bolojan said, a plan complicated by the fact that several of those countries are managing their own drought-driven shutdowns at the same time.
A REGIONAL PROBLEM
Romania is not alone in facing this strain. In Hungary, the Danube’s record-low levels have pushed the country’s only nuclear plant close to a full shutdown for the first time in decades, a milestone that would have been unthinkable in a normal water year. Moldova, which depends heavily on imported electricity, including supplies from Romania, has already asked residents to cut consumption during peak hours as it watches the situation upstream.
The overlap points to a wider vulnerability across the Danube basin, where multiple countries rely on the same river for both drinking water and power generation. When flow drops this far below seasonal norms, the effects move downstream quickly, touching plants and grids well beyond the point where the drought first hit hardest.
Cernavoda’s situation illustrates how tightly nuclear generation in the region is tied to river conditions. Reactors need a steady, sufficient volume of cooling water to operate safely, and when that volume falls too far, operators have little choice but to reduce output or shut down entirely, regardless of demand. That constraint puts engineering crews like the ones working the Bala Canal barrier in a race against a clock set by the weather rather than by mechanical failure.
The barge maneuver itself reflects an improvised, short-term fix rather than a structural solution. Urjan’s own estimate, that the barrier might buy Cernavoda four extra days of operation, underscores how narrow the margin has become. Even with the barrier in place, the plant remains dependent on rainfall patterns and temperatures that Romanian authorities cannot control.
Bolojan’s government now faces a two-part challenge: keeping the barrier and dredging operations effective long enough to matter, and managing public electricity demand so that any reduction in Cernavoda’s output does not translate into blackouts during the hottest and highest-demand hours of the day. The appeal to households to voluntarily cut evening usage is aimed directly at that second piece, buying operational headroom on the grid side while engineers work the river.
Whether the barge barrier holds up through Friday and beyond will determine how much additional time Cernavoda’s second reactor gets before facing the same fate as the first. Urjan’s numbers suggest the difference amounts to a matter of days, not weeks, which leaves Romanian officials watching river gauges as closely as they watch the plant’s reactor readings.
For neighboring Hungary and Moldova, Romania’s response offers an early look at what a prolonged Danube drought could force other governments to attempt as their own water levels keep falling through the rest of the summer.
