The unusually high temperature of sea water led to the closure of the Swedish nuclear power plant, since the water reached a temperature of 25 degrees Celsius. The water of this temperature is too warm to cool the nuclear reactors with the help of sea water.
Swedish state-owned energy company Vattenfall was forced to shut down one of its reactors at the Ringhals nuclear power plant.
Ringhals is the largest nuclear power plant in Northern Europe and accounts for one fifth of all electricity consumption in Sweden. The plant has two old reactors, Ringhals 1 and 2 and two new ones, Ringhals 3 and 4.
Seawater is used to cool the reactors, and each reactor has a limit on how high the water temperature can be reached before it needs to be shut off for safety reasons.