“Personally, I’m not worried,” Rozhkov said.

His shower came courtesy of nuclear residential heating, which remains exceedingly rare and was introduced in the remote Siberian town of Pevek only a year ago. The source is not a typical reactor with huge cooling towers but is the first of a new generation of smaller and potentially more versatile nuclear plants — in this case aboard a barge floating nearby in the Arctic Ocean.

As countries from across the globe meet in Scotland this week to try to find new ways to mitigate climate change, Russia has embraced nuclear residential heating as one potential solution, while also hoping it can bring a competitive advantage. Companies in the United States, China and France are considering building the type of small reactors connected now to Pevek’s waterworks.

“It’s very exciting,” Jacopo Buongiorno, a professor of nuclear science and engineering at Massachusetts Institute of Technology, said in a telephone interview. These small reactors, he said, could also warm greenhouses or provide heat for industrial purposes. In bringing to life the new approach, he said, “the Russians are ahead.”

Nuclear-powered residential heating is distinct from running space or water heaters with electricity generated from nuclear sources. Direct nuclear heating, tried in small pockets of Russia and Sweden, circulates water between a power plant and homes, transferring heat directly from fissioning uranium atoms to residences.

Warming homes with nuclear power also has environmental benefits, advocates of the idea say. Primarily, it avoids wasting the heat that is typically vented as steam through the conical cooling towers of nuclear plants, and instead captures it for use in residential heating, if customers are fine with it.

Still, some experts are concerned about the potential risks, pointing to the many spills and accidents on Soviet and Russian submarines and icebreakers that used similar small reactors. Nuclear submarines sank in 1989 and 2000, for example.

“It is nuclear technology, and the starting point needs to be that it is dangerous,” said Andrei Zolotkov, a researcher with Bellona, a Norwegian environmental group. “That is the only way to think about it.”

Rozhkov’s wife, Natalia Rozhkova, was initially skeptical. They can see the new nuclear facility, which is about a mile away, from their kitchen window. She said she “worried for the first two days” after their apartment was connected to one of the cooling loops of the reactors. But the feeling passed.

“Whatever is new is scary,” Rozhkova said. Still, somebody has to be first, she suggested, adding, “We were the closest, so they hooked us up first.”

The experiment in Siberia, Buongiorno said, could play a vital role in convincing countries that using nuclear power to limit climate change will require using it for more than just generating electricity, the source of about a quarter of greenhouse gas emissions.

“Decarbonizing the electrical grid will only get you one quarter of the way,” he said. “The rest comes from all these other things.”

Yes, but a nuclear shower? Buongiorno said he would take one — but conceded that “obviously this is not going to work if people don’t feel comfortable with the technology.”

The experiment with nuclear heating hardly makes Russia a crusader on climate change. One of the world’s heaviest polluters, it has adopted contradictory stances on global warming, of which Pevek itself is an example: At the same time it is switching its heating to nuclear power, rather than coal, it is benefiting from climate change in the Arctic, reviving as a port as shipping lanes become more navigable.

The nuclear facility in Pevek is aboard the Akademik Lomonosov, a barge about the size of a city block. The idea of small reactors is not new. In the 1960s, before the anti-nuclear movement gained traction, they were seen as a promising technology. The United States operated a barge-based reactor to electrify the Panama Canal Zone from 1968 to 1976, and Sweden used nuclear heating in a suburb of Stockholm from 1963 to 1974.

Now, two other sites in Russia besides Pevek use nuclear residential heating; however, in those cases, it is a byproduct of large electrical plants.

Soon, in Pevek, the town’s community steam bath, or banya, will also be nuclear-powered. The Russian state nuclear company, Rosatom, connected the reactors to the heating pipes in one neighborhood in June 2020. It is now expanding the hot water service to the whole town, which has a population of about 4,500.

Residents cannot opt out of getting nuclear-powered heat, but they have mostly welcomed the new plant. Maxim Zhurbin, the deputy mayor, said nobody complained at public hearings before the barge arrived.

“We explained to the population what would happen, and there were no objections,” he said. “We are using the peaceful atom.”

Irina K Buriyeva, a librarian, said she appreciated the plentiful heat and electricity. Of the risks of a radiation leak or explosion, she said, “We try not to think about it, honestly.”

Russia is first, but hardly an outlier, in developing small civilian reactors. This month, President Emmanuel Macron of France proposed an expansion of his country’s extensive nuclear sector with small reactors as part of the solution to climate change. China is building small floating reactors modeled on the Russian design.

Companies in the United States, including General Electric and Westinghouse, have about a dozen designs ready for testing starting in 2023. In an extreme example of miniaturization, the U.S. military has ordered a reactor small enough to fit in a shipping container; two companies, BWXT and X-energy, are competing to deliver the air-cooled device.

Germany, however, has taken a different path: The country decided to close all of its nuclear plants after the Fukushima disaster in Japan in 2011.