Slovenia’s Krško nuclear power plant has returned its reactor to 100 per cent power following cooler weather, rainfall and improving conditions on the Sava River. The changes eased environmental restrictions that had constrained production since early August.
Derating steps as river flows and temperatures changed
The plant initially cut output to 80 per cent when very low river flows coincided with elevated water temperatures. As conditions improved, generation was increased to 90 per cent. On the evening of 18 August, the unit returned to full reactor power.
Grid deliveries remain below typical levels
Electricity supplied to the grid has not yet fully returned to normal. During the afternoon, the plant was delivering approximately 660 MW, compared with more than 700 MW under typical operating conditions.
A portion of the shortfall is linked to continued use of the cooling-tower system. Some of the plant’s own electricity is being consumed to operate cooling infrastructure, which reduces dependence on Sava River water while helping keep operations within environmental limits.
Hydrology-linked nuclear availability in regional markets
The episode highlights a direct connection between extreme summer hydrological conditions and nuclear availability in the region. Krško is described as a major source of stable generation for both Slovenia and Croatia. Partial derating is therefore relevant for cross-border balances and wholesale prices.
