Several employees at the Russian Federal Nuclear Centre in the city of Sarov have been detained after making "an attempt to use the work computing facilities for personal ends, including for so-called mining," a spokeswoman for the centre, Tatiana Zalesskaya told Interfax news agency.
"Their activities were stopped in time," she added.
"The bungling miners have been detained by the competent authorities. As far as I know, a criminal case has been opened regarding them," she added, without saying how many were detained.
The centre is overseen by Rosatom, the Russian nuclear agency, and works on developing nuclear weapons.
Such attempts "at our enterprises will be harshly put down, this activity technically has no future and is punishable as a crime," the centre's spokeswoman said.
In 2011, the centre switched on a new supercomputer with a capacity of 1 petaflop, which at the time made it the twelfth most powerful in the world, Russian television reported.
During the Cold War, Sarov was a top-secret city in the Nizhny Novgorod region, about 500 kilometres (300 miles) east of Moscow. Its Soviet era name was Arzamas-16.
The centre was the birthplace of the Soviet Union's first nuclear weapons.
Sarov is still a closed city whose inhabitants are subject to travel restrictions.
Vladimir Putin visited the nuclear research centre in 2012 while campaigning for president.
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