Bulgaria's Kozloduy Nuclear Power Plant is stable despite drought on the Danube: crises in Paks and Cernavodă point to grid risks, not safety risks.

As the region grapples with the consequences of the record-low water level of the Danube and a prolonged heat wave, reassuring news come from Bulgaria: two units of the Kozloduy Nuclear Power Plant continue to operate without interruption

According to the Bulgarian Ministry of Energy, both active blocks (Blocks 5 and 6, VVER-1000 reactors) are reliably delivering electricity to the grid. Expert assessments show that, even if the river level continues to fall at the current rate, there will be no need to reduce production capacities in the next three weeks. Bulgarian authorities confirmed that they are in constant contact with the competent authorities in Serbia and Romania for coordination and monitoring of the state of the river route.

A reminder of the regional context: Paks, Cernavoda, and electricity imports from Ukraine

This stability of Bulgaria comes at a moment when neighboring operators on the Danube were forced to take radical measures:

• We recall the Hungarian Paks (or “Paks”): Hungary, due to the critical drop in water level and overheating of the river water, was forced to drastically reduce its power output and shut down the Paks NPP, which otherwise covers over 40 percent of domestic production.
• Romania crisis and imports from Ukraine: The Romanian operator Nuclearelectrica was forced to completely disconnect Block 1 from the grid at the Cernavodă Nuclear Power Plant. To cover the sudden energy deficit and ease price surges on the market, Romania declared a 30-day state of readiness and began emergency imports of electricity from Ukraine (via the Moldovan company Energocom), using surpluses that the Ukrainian system feeds into the pan-European ENTSO-E network.

Comment: security is not at issue, but the electricity system is

In relation to the Danube events, it is important to underscore the key fact: here the problem, of course, is not the safety of the technology itself — nuclear plants are capable of a controlled shutdown and respond strictly according to designed procedures before any cooling parameter endangers the reactor's safety.

However, the real problem arises for the power system of this part of Europe.

When, at the height of the summer demand peak (driven by air-conditioner use and a drought that simultaneously reduces hydroelectric production at plants such as Đerdap), gigawatts of base-load power drop from Paks and Cernavodă from the grid, the regional electricity system enters an extremely tense state. The pressure automatically shifts to the remaining stable sources — such as Bulgaria's Kozloduy — and pushes the states into expensive emergency imports.

The Kozloduy case shows that good cooling conditions and adequate planning provide the necessary breathing room of several weeks, but the regional dependence on the Danube's hydrology remains a warning for all future nuclear investments in the Balkans, including the one in Serbia.

S.A.