Several scientists working at a nuclear weapons facility in Russia were arrested this week on the suspicion that they used one of the country’s most powerful supercomputers to mine bitcoins, the BBC reported.

The alleged infraction took place at the Federal Nuclear Center in Sarov, a top-secret area surrounded by barbed-wire fences where the Soviet Union’s first nuclear bomb was produced during the Cold War.

“There has been an unsanctioned attempt to use computer facilities for private purposes including so-called mining,” the center’s press service said, according to the BBC and the Interfax news agency. “As far as we are aware, a criminal case has been launched against them.”

Kingston Reif, director for disarmament and threat reduction policy at the Arms Control Association, said in a phone interview that the issue touched on numerous security-related concerns, some of which were compounded by the fact that cooperation between the United States and Russia over its stocks of nuclear materials — the largest in the world — had ended over the past few years.

“One of the long-standing concerns that experts have had about the Russian nuclear complex is the potential for insider threats — the potential that Russian nuclear scientists or employees could, in search of a payday, siphon off material that could be used in a nuclear radiological device or help a terrorist group,” Reif said. “That said, it’s a good thing that the facility’s security system appears to have been alerted to the unauthorized use of the computer quickly and the suspects quickly apprehended. Let’s also hope the supercomputer is closely monitored when it’s not hooked up to the net as well.”

The supercomputer that was purportedly used was not supposed to be connected to the Internet for security reasons. Facility operators uncovered the transgression after they were alerted that it had been connected.

The scientists were handed over to the Federal Security Service, the BBC reported. Cryptocurrencies require a great deal of computer energy to mine, the BBC reported.

The nuclear center employs about 20,000 people; it’s supercomputer can do the equivalent of 1,000 trillion calculations per second, the BBC reported.

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