Bulgaria’s Kozloduy nuclear power plant has reduced output from unit 5 after exceptionally low Danube levels constrained cooling-water availability. Regulators said the plant remains within safe operating limits. The reduction is linked to river conditions rather than an identified safety breach.
The Danube river level has fallen to around 20.64 metres under the Baltic measurement system following prolonged dry conditions across Europe. Unit 5 is currently the only reactor affected. The situation is being managed through plant procedures for low-water operation .
Staged low-water procedure for Kozloduy
Kozloduy uses a staged procedure for low-water conditions. Monitoring intensifies when levels drop below 21.5 metres. Additional reserves and preparations for a controlled shutdown are introduced around 21 metres.
If the shore pumping station cannot provide sufficient water, output reductions can become necessary at about 20.5 metres. A further decline toward 20.3 metres could require substantially deeper reductions in electricity generation. At around 19.7 metres, almost all shore pumps would be shut down .
Market impact tied to reduced firm generation potential
The immediate effect of the low-water measures is reduced available generation rather than a safety issue. For the regional electricity market, the episode highlights how thermal and nuclear plants along major rivers are exposed to volatile hydrological conditions. Further declines in Danube levels could remove additional firm generation from an already weather-sensitive SEE power system.
