Paks nuclear power plant free to overheat the Danube in the future?

Once in 2022, twice in 2023, and again this year, the output of the Paks nuclear power plant had to be reduced due to the increased water temperature of the Danube. The government would reduce the burden on the plant with a new decree, with Paks II potentially changing the status quo in the future.

On 15 and 16 August, the power output of the Paks nuclear power plant had to be reduced because the water temperature of the Danube exceeded the limit of 29.5 degrees Celsius and then 29.75 degrees Celsius. The output of several units was reduced by 80 megawatts each, and by 18 August, the water temperature in the Danube had moved in a favourable direction, allowing the first two units affected to operate at nominal capacity again, while the fourth unit is now operating at 50 percent capacity due to planned maintenance.

In practice, however, as Portfolio points out, this means that the net output of the plant has increased by 70 MW since the 50 percent capacity is greater than the previous total load.

New regulation for Danube temperatures near the Paks nuclear power plant

According to current regulations, the temperature of the Danube within half a kilometre of the power plant’s cooling water outlet cannot exceed 30 degrees Celsius in order to protect the environment and wildlife. Should the water temperature in a section 500 metres downstream from the cooling water intake exceed the limit of 29.5 degrees Celsius, power output must be reduced by 80 megawatts for every 0.1 degrees Celsius, according to the plant’s internal regulations.

However, as Népszava writes, this may change, based on a decree that came into force on Thursday evening, 15 August, and was signed by the energy minister, which states that in order to ensure the security of supply, the energy minister—after informing the minister responsible for the environment and water—may authorise the 30-degree limit to be exceeded in certain cases.

The specific justifications and circumstances for such a decision, for how long the higher temperature can be sustained, and what exactly this temperature may be, are not detailed in the regulation. Moreover, as Népszava points out, Csaba Lantos, as Minister of Environment, must notify himself about the decision, as the minister responsible for environmental issues as well.