Istanbul, August 13 (HNA) – Romania’s nuclear energy group, Nuclearelectrica, announced on Thursday that it had initiated procedures to carry out a controlled shutdown of Unit 2 at the Cernavodă Nuclear Power Station due to cooling problems in the reactors, and the shutdown was completed by midday.
The shutdown procedure for Unit 2 at Cernavodă began at 08:00 (CET) on the morning of 13 August; power was gradually reduced, and from 11:00 onwards, the nuclear unit was disconnected from the national electricity grid. As Unit 1 of the Cernavoda nuclear power station was shut down on 28 July, Romania’s national energy system will continue to operate indefinitely without nuclear power.
According to experts, the low water level in the River Danube meant that the reactors could no longer be cooled, necessitating the shutdown of both reactors. Interventions carried out in the Bala branch area, aimed at diverting part of the flow to the Old Danube branch and, indirectly, to the nuclear power station, did not yield the expected results, and Nuclearelectrica announced that a controlled shutdown of Unit 2 is also likely.
The two units together provide nearly 20 percent of the national electricity consumption from the grid and are the largest generating units in Romania, with 680 MW each. No date has been announced for restarting, as it all depends on the flow of the Danube.
Nuclearelectrica has activated the force majeure clause, which allows it to no longer comply with its electricity sales contracts.
According to Magyar Villamos Művek (MVM), the Hungarian operator, the water level in the Danube is now 28 centimetres below the previous record, set in 2018, which was itself one metre below the 100-year minimum water level used in the design of Paks nuclear power plant, which opened in the early 1980s.
It has already been reducing the total plant’s output and stressed that there was no safety issue, but said that “although the current extremely low water level and water flow rate would allow sufficient water to cool the units, the suction level of the pumps required for this is higher than the current low – and expected to continue to decrease – water level, so they cannot perform their task”.
“Of course, the nuclear power plant is prepared for extraordinary situations, including those with a low probability of occurrence. We have developed procedures for dealing with the so-called low water situation of the Danube. Low water conditions are divided into 4 stages based on the levels measured at the water intake … we are currently in stage 3.
“According to forecasts, there is a realistic chance of a level 4 event: at this point, all units of the nuclear power plant will have to be shut down, energy production will cease from then on, and the units will have to be cooled. This requires 5 cubic metres of water per minute, compared with 100 cubic metres per second for the operating units.
“We can currently give an estimate for the complete shutdown – due to water forecasts that change several times a day: according to our calculations, the time frame within which we must implement the shutdown is 24-72 hours.”