A 262-foot smokestack at a German nuclear power plant tipped onto its side seconds after the charges were triggered, and the 157-foot steel sphere that contained the reactor then descended, cleared to be cut up for scrapping, so the site could cease to be a nuclear power plant after 21 years of dismantling.

There are basically two ways to get rid of a very tall chimney. You can take it apart from top to bottom, a few feet at a time. Or you can set off explosives at the base and let the whole thing collapse in seconds.

PreussenElektra I opted for the second option. The German company owns the former Stadium nuclear power plant on the Elbe River, west of Hamburg, and on Friday, September 4, the plant’s 262-foot-long exhaust stack exploded.

Freimuththe contractor responsible for the demolition of the Stadium, called on a specialized company to carry out the explosion itself. The charges went off around 1 p.m. and the pile toppled onto its side within seconds, according to Kreiszeitung Wochenblatt, a local newspaper. About a hundred guests were present and watching from afar. It’s honestly more of a farewell than most fireplaces.

World Nuclear News quoted plant manager Marco Albers as saying he was satisfied that the chimney “can be dismantled safely and as planned.”

I went to get the chimney weight and came back empty, so I can’t tell you exactly how much chimney hit the ground that day. Everything I found, from the company and the German press, gives its height and that’s it.

So what did a smokestack do in a nuclear power plant?

If you grew up near a coal-fired power plant or steel mill, a tall chimney probably means smoke. But nothing burns in a nuclear reactor. There is therefore no smoke to evacuate.

The Stadium’s chimney was essentially the outlet for the factory’s ventilation system. The factory cleaned its exhaust air and monitored it constantly, and it was up the chimney that this air exited. It increased in 1970, so it had already been in place for some time when the reactor first sent electricity to the grid.

The reactor itself was a 640 megawatt pressurized water design. This is the same basic type as that of about two-thirds of the reactors licensed to operate in the United States today, according to figures from the Nuclear Regulatory Commission.

In a reactor like this, the water around the core is kept under such pressure that it cannot boil, and it heats a second water loop that produces steam for the turbine. This operated for 31 years and has been closed for over 20 years.

A 157-foot steel sphere still stands

With the pile gone, the site is nothing more than an office building, some unused warehouses and the plant’s steel containment sphere, World Nuclear News reports.

If you’re not familiar with reactor anatomy, a containment vessel is the airtight shell that surrounds the reactor and its plumbing. It’s there to keep anything radioactive inside in case something serious goes wrong.

The one at Stade is a steel sphere 157 feet in diameter, with walls about an inch thick. It was inside a concrete reactor building, and demolition crews have spent the months since March 31 tearing down that building around it. We talked about the 4.4 ton wrecking ball they used on the concrete last August, and by the looks of it, it did its job.

Before all this began, PreussenElektra used the empty sphere as a location for a video and sound installation called ORBITALE. About 1,300 people went, according to the company’s 2025 annual report, and apparently the acoustics inside an empty containment ship are unlike anything else in Germany. Farewell to a power plant is rather elegant.

The sphere then comes out. It has already been allowed to be cut up and recycled as scrap metal.

So why is a regular demolition company allowed to demolish all this?

Because the nuclear side of the work is almost complete. There has been no fuel for a long time. The reactor pressure vessel (the large steel pot in which the fuel was held) and the most contaminated components were removed more than ten years ago. Since then, the company has controlled the contamination of the rest of the factory piece by piece, right down to the wall plugs in the office buildings, reports Kreiszeitung Wochenblatt. The reactor building and sphere underwent the same treatment, with more than 129,000 square feet of surface area monitored and more than 500 samples analyzed, according to regional news site Die Niedersachsen.

Freimuth deals with what PreussenElektra calls conventional demolition. This is the stage where buildings that have been checked and cleaned are demolished like any other old building, and the pile was one of them.

The destruction of the Stadium lasted more than 20 years

In case you’re wondering how long this all took, know that the company has been dismantling the Stadium for about 21 years and conventional demolition only began a few years ago.

The first batch of 17 buildings, totaling about 6.25 million cubic feet, is already gone. Two other phases take place side by side. One covers five building complexes and the other ten, according to World Nuclear News.

Once the remaining work is completed, the site is released from nuclear regulatory oversight. That’s when regulators approve and the property ceases to be managed as a nuclear site. There is, however, one building that remains in place: a storage facility for low- and medium-level radioactive waste.

Still, it’s quite different from what we see in many American factories. In San Onofre, California, for example, spent fuel is stored on site in sealed steel containers, and it will remain there until the federal government finds a place to transport it. The Stadium, as I mentioned, no longer has any spent fuel.

PreussenElektra wants the steel sphere to disappear by the end of 2026 and the site to be vacated in fall 2027. If both dates are met, World Nuclear News says this will make Stade the first fully dismantled commercial pressurized water reactor in Germany, around 24 years after it stopped producing electricity.

Photo: Wolf-Christian Nerger/PreussenElektra