Police said several people were detained after they were found transporting the scrap from the 18-miles exclusion zone around the Chernobyl nuclear power station, which exploded in 1986.
The helicopter, an Mi-8 "Hip", was found to emit up to 30 times the legal level of radiation.
According to a statement issued by the elite SBU special services, the criminals "tried to take an Mi-8 helicopter out of exclusion zone to use it as an original coffee shop in one of Ukraine's cities".
A workhorse of the Soviet armed forces, the Mi-8 helicopter is capable of carrying up to 28 people, although it was not made clear how many customers the gang had been hoping to seat.
Almost 2,000 helicopter sorties were ordered to douse the Chernobyl station after a reactor suffered melt down.
As a result, many of the helicopter pilots received lethal doses of radiation.
The Chernobyl disaster released at least 100 times more radiation than the atom bombs that were dropped on Nagasaki and Hiroshima.
Source: Telegraph UK