Hungary’s Nuclear Power Returns as Rain Lifts Danube Water Levels
Hungary expects its only nuclear power plant to resume producing electricity as early as Monday evening after one of the turbines at the Paks nuclear plant is switched on, Prime Minister Peter Magyar said.
Hungary and Romania have been hit in the past weeks by power supply issues after the heatwaves and the lack of rainfall this summer led to the lowest water levels of the Danube in nearly 90 years. Hungary and Romania were forced to curb the respective nuclear power output of their plants that use the water from the river for cooling of the reactors.
Last week, Hungary shut down the Paks Nuclear Power Plant, for the first time in 44 years, due to the continued drop in the water level of the Danube, Hungarian Prime Minister Peter Magyar said on August 2.
The water levels on the Danube started rising at the end of last week as rain started falling in the Austrian catchment areas of one of Europe’s biggest rivers.
On Thursday, Hungary’s Magyar said: “We are already nine centimeters above the Danube’s Sunday low point, and rain is expected in the Austrian catchment areas.”
Despite the good news about rising water levels, last week Hungary reiterated calls for “a strong need for voluntary reductions in electricity consumption” amid a heatwave that is gripping Europe these days.
On Monday, Magyar said that “The Danube's water level was 19 centimeters above the low point from one week ago this morning. The reconnection process of a Paks turbine has begun. From evening, the No. 3 turbine of the second unit will also generate power.”
Romania, another European country relying on nuclear power output from a power plant on the Danube, last week blasted a rock formation and sank barges filled with rocks to deviate the Danube’s flow and secure enough water for cooling the reactors of its only nuclear power plant at Cernavoda.
The operation was successful, and water levels at Cernavoda rose this week, which means the second nuclear reactor at the plant could operate for at least nine more days.
By Tsvetana Paraskova for Oilprice.com
Danube water level rising: Another Paks nuclear plant turbine may restart
The Danube's level at Paks, south of Budapest, has risen by about 19 centimetres from its previous low, allowing the first additional Paks nuclear plant turbine to be restarted and reconnected.
The phased reactivation of the previously shut-down capacity has begun at the Paks Nuclear Power Plant, after the level of the River Danube started to rise.
Once the river had climbed back above the critical low recorded a week earlier, it became possible for one turbine to start producing electricity again from Monday evening. The reconnection is taking place under strict technical and safety conditions.
At the beginning of August, the Danube’s water level dropped to a historic low, reaching minus 134 centimetres at Paks. As a result, three of the four reactor units had to be shut down gradually and in a controlled manner. Only a single turbine remained in operation.
Thanks to rainfall over the Austrian catchment areas, the river began to swell along its upper reaches. That flood wave has now reached the Paks section as well. A rise of 19 centimetres in the water level provides enough volume to extend safe cooling.
Plant increases power output
With the launch of another generating unit, the plant’s output to the grid will increase from the 240 megawatts recorded during the critical period to 500 megawatts.
During the restart and operation of the nuclear power plant, nuclear safety takes absolute precedence over electricity production, so the reconnection has to meet several stringent requirements. In terms of adequate pump pressure, the rise in the Danube has restored the efficiency of the cold-water channel pumps, ensuring that the condensers can be cooled.
The systems responsible for cooling the reactor core and the spent fuel pools must function flawlessly; they remained continuously in operation even during the period of low water. Before the turbine can be started, an adequate vacuum has to be created in the condenser. The quality of the secondary-circuit water also needs to be checked.
The reactor’s thermal output and the volume of steam are not adjusted in one go but synchronised step by step with the generator’s connection to the grid, according to a strict timetable.
Around half a million components also have to be subjected to diagnostics. Operating specialists will ensure that the heat and the temporary shutdown have not caused microscopic material defects in the equipment.
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