Finished decades ago for 4 billion dollars, a sodium cooled breeder reactor in Kalkar never split an atom, and its cooling tower now spins a swing ride
A giant steel arm swings sixteen riders out over a 200 foot drop inside a windowless concrete shell on the German Dutch border.
The walls around them curve inward like the inside of an hourglass.
Paint covers the concrete in the shape of a mountain range.
Construction of the reactor had already finished, but a new state government was clearly against the project, and opposition mounted sharply following the disaster.
Nobody screaming on that ride is thinking about nuclear fission.
But the tower under their feet was built to cool a reactor that was supposed to breed its own plutonium fuel.
So why does a thrill ride now spin inside it?
Why a nuclear cooling tower turned out to be perfect carnival hardware
A cooling tower is, structurally, just a very large empty cup. Hyperboloid concrete shells like the one at Kalkar were built to pull warm water down through a cascade of air so it could cycle back to condense steam from a turbine. That function needs no machinery inside the shell itself, only open air and a sturdy concrete skin, which happens to be exactly what a thrill ride needs too.
So when the reactor beneath it was abandoned, the tower was left as the single most structurally overbuilt, column free, weatherproof cavity in the region. A rotating swing arm needs clearance and overhead anchoring and a structure that will not flex under repeated centrifugal load.
A reactor grade cooling tower was engineered to outlast the plant it served by decades. That is the quiet irony behind the ride, since its enormous built in scale became an amusement engineer’s dream shell once the water never came.
Inside the shell nobody expected to see again
The reactor at the center of all this was the SNR-300, a sodium cooled fast breeder designed to squeeze more energy out of limited uranium supplies by generating its own plutonium as it ran. It was built near the town of Kalkar, completed but never taken online, designed to output 327 megawatts.
Construction had dragged on for thirteen years through the 1970s and into the mid 1980s. Then came Chernobyl.
Construction of the reactor had already finished, but a new state government was clearly against the project, and opposition mounted sharply following the disaster. Within a few years the federal government made its decision final, and the project was abandoned because continued construction and required maintenance would have made operation unviable.
What was left standing was a complete, fueled for nothing power station that had cost roughly four billion dollars and never produced a single kilowatt hour.
What the sale price says about a failed reactor’s real value
A few years later, a Dutch entrepreneur named Hennie van der Most bought the entire site. Known for his peculiar past investments, including a chain of fried chicken restaurants and a golf course on a former NATO camp, he turned the nuclear site into an amusement park that opened in 1995.
The purchase price, reported at around three million dollars, was a rounding error against the plant’s original construction cost.
Inside the cooling tower, a swing ride spins beneath the structure’s original concrete dome, and a climbing wall rises along its curved interior surface. The old control room, with its original wall panels, is now rented out for conferences.
Today the park draws a genuinely large crowd for a former nuclear site, about 650,000 visitors a year, most there for roller coasters rather than atomic history.
Where the comparison runs out
The Kalkar story is not really one about reuse succeeding everywhere. Most retired cooling towers in Europe are demolished rather than converted, because turning one into a safe public attraction requires structural certification and fire exits that most utilities never budget for once a plant is decommissioned.
A campaigner pushing to save more of Britain’s towers put it plainly, arguing that “you don’t have to look too far to find imaginative examples internationally of cooling towers that have been reused,” since their enormous scale makes them an obvious draw for activities needing serious elevation.
Even at Kalkar, the reuse is partial. Two thirds of the original plant’s buildings reportedly sit empty behind the rides, a reminder that one dramatic swing ride does not erase the scale of what the site was meant to be. The park’s own official history page describes the vertical swing as the hotel and leisure complex’s signature attraction, built around the reactor building and cooling tower left standing on purpose.
A different kind of second life for industrial concrete
What Kalkar demonstrates, more than a recipe for recycling power infrastructure, is how durable these structures are built to be. The same engineering logic that makes a cooling tower survive decades of thermal cycling is what let Kalkar’s shell stand ready for a second purpose long after the plant died.
Elsewhere, engineers are testing subtler reuses of old fossil infrastructure, from oilfield wastewater yielding battery grade lithium to pumped storage schemes like the one at Niagara Falls that send the same water through turbines twice.
None of it looks as strange from the outside as a swing arm spinning inside a reactor cooling tower. The tower at Kalkar was never meant to hold tourists, only steam and falling water, and it holds neither today, just the sound of riders and wind moving through a shell built, at enormous cost, to do something it never got the chance to do.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
