STA, 22 July 2022 - The country's sole nuclear power station NEK is operating at full power and in line with administrative restrictions despite the low water level of the Sava river and high air temperatures.
The cooling towers are operating at full capacity. The plant's efficiency is slightly lower, which is why good coordination of the water regime with the hydroelectric power plants on the lower Sava is important, NEK said.
The plant's output is 1.5% lower than normal these days, but NEK has been running continuously for 443 days since the last scheduled maintenance was completed in May last year, the power station told the STA.
NEK uses the water from the Sava for cooling or extraction of heat which cannot be used for electricity generation but is needed to cool the condenser. In this process, pumps push the water captured in the river through the condenser and return it to the Sava. The flow rate in the condenser is about 25 cubic metres per second.
As the resulting warming of the river water could affect the biological characteristics of the Sava, there are administrative restrictions as to how much the water temperature is allowed to rise and how much water can be used. The cooling towers are activated whenever environmental conditions require it.
In extremely adverse weather conditions, compliance with these restrictions requires a reduction in the power plant's output. However, in order to reduce the plant's dependence on the river, NEK's cooling tower system was modernised and expanded in 2008.
The cooling system of NEK's tertiary circuit was improved and four additional cooling cells built. Before this upgrade of the cooling tower system, NEK operated at reduced power for 93 days in 2003 due to environmental constraints related to the Sava river.