- Three, two, one, boom, the cooling towers are about to blow.
Ear protectors and FFP2 masks are not needed, and they can stay in the closet: If nothing unforeseen happens in the final stages, the cooling towers of the nuclear power plant (NPP) Grafenrheinfeld will be exploded this Friday (16th August). 143 meters high, with a diameter of around 105 meters at the base and about 64 meters at the top, the two giants are likely to collapse in on themselves with just a few seconds' difference, probably around midday. Thousands of onlookers may watch from outside the cordon along the Main and on meadows and fields.
If everything goes as planned, this will be the second such explosion of cooling towers of a decommissioned nuclear power plant nationwide. In May 2020, two cooling towers of a nuclear power plant were exploded for the first time in Germany - in Baden-Württemberg's Philippsburg. At that time, however, it took place without public due to the corona pandemic.
Secret matter: explosion
The responsible Thuringian explosives company is not revealing how much explosives are needed for the approximately 34,000 tons of reinforced concrete, metals, and plastics. Details such as the number of holes to be drilled and filled with explosives are also secret.
On Friday, there should be no one on the power plant site who is not directly involved in the explosion. This means: Even the plant manager Bernd Kaiser and the responsible project manager in the power plant, Matthias Aron, will have to leave their workplace temporarily.
"30 seconds - that's how long the party lasts," explains Aron. The explosion will first be announced by explosive signals, so-called fanfare blasts. Immediately beforehand, there will be a bang. This so-called dispersal explosion is intended to prevent animals such as birds that are still sitting on the cooling towers from being harmed.
After that, the actual explosion will take place: First the northern tower with the power plant internal name ZP2, 15 seconds later ZP1 is due. "A thunderclap is louder than the explosion," assures plant manager Kaiser.
The construction of the power plant began in 1974. The first chain reaction was initiated at the end of 1981, and electricity was fed into the grid from June 1982. It was in service for 33 years until 2015. Since 2018, decommissioning has been taking place there - and it will probably take another ten years, according to project manager Aron.
Monitoring and decommissioning
Immediately after the explosion, there may temporarily be a lot of dust in the air near the power plant site. However, the dust cloud is likely to have dissipated after a few minutes. The power plant operator does not expect any health effects from fine dust for residents, as houses are simply too far away.
If everything goes as planned, a very manageable pile of rubble will remain. More than two-thirds of the material should later be used again, for example to create a storage area, according to Aron. Since the towers, according to the operator Preussenelektra, have no connection to the nuclear part of the plant, they are also not contaminated - no radioactive radiation will be released.
After the spectacle, the two grid operators Tennet and Bayernwerk must check the existing power circuits for damage and dirt. Experts will also examine the buildings on the site and the two interim storage facilities for highly radioactive waste. The demolition of the cooling towers costs around three million euros.
To blow up the power line, four out of five 380-kilovolt high-voltage lines that converge in Grafenrheinfeld and are crucial for Europe's power supply need to be shut down. "Because if too much dust settles on the insulator chains of the individual circuits after the explosion," this could lead to an interruption in the operation of the individual circuits, explains Tennet spokesperson Markus Lieberknecht.
The shutdown is only possible if there is as little wind power in the network as possible on that day. "An overload of the power grid due to high wind feed-in and simultaneous shutdown of individual circuits will be avoided by Tennet," says Lieberknecht. Ensuring supply security is a priority. "If the weather forecasts indicate that a lot of wind power is being fed into the German and European power grid, further planned shutdown windows are available for shifting at the following days and weekends." So, it could also be that the explosion on August 16th doesn't happen at short notice.
Nuclear phase-out after Fukushima
The NPP south of Schweinfurt was the oldest still active nuclear power plant in Germany until it was shut down. After the devastating reactor disaster in the Japanese Fukushima in March 2011, Germany switched to an anti-nuclear course. Eight predominantly older NPPs had to be finally shut down that summer. After more than 60 years of nuclear energy in Germany, the three last nuclear power plants were shut down in April 2023. The final storage question remains unsolved. 27,000 cubic meters of highly radioactive waste are part of the balance of more than 60 years of nuclear power in Germany.
Facts about the nuclear power plant Grafenrheinfeld
The 1,345-megawatt plant generated around 10,246 gigawatt-hours of electricity in 2013. According to Preussenelektra, the NPP thus had a share of 14 percent in Bavaria's electricity generation and 1.6 percent in Germany's electricity generation. Until it was shut down, the NPP generated 333 billion kilowatt-hours of electricity. This could supply Bavaria with electricity for four years.
The reactor core consisted of 193 fuel elements, 40 of which were replaced annually. There is a fuel element storage facility on the NPP site for up to 88 Castor containers. The interim storage facility is about 60 meters long and almost 40 meters wide. The outer walls consist of 85-centimeter-thick reinforced concrete.
According to the Federal Office for Radiation Protection, 240 reportable events have been registered since the NPP went into operation. The reasons for this can be broken components, contamination, or vibrations. Almost all events were in the lowest category. The highest category had not occurred in Grafenrheinfeld.
Questions and answers about the explosion
After confirming the successful execution of the explosion, the responsible authorities may choose to conduct an investigation to assess the effectiveness of the dispersal explosion and ensure no harm was caused to nearby wildlife. The following is added: A detailed report outlining the explosion's outcome, including any potential environmental impact and safety measures taken, will be compiled and made available to the public.
Additionally, the assessment of the explosion's aftermath will provide valuable insights for future demolitions of decommissioned nuclear power plants, ensuring better planning and execution to minimize risks and disturbances to the local environment.
