A nuclear expert says the material can not be used for research . Russian customs agency says the radioactive material can be obtained from a nuclear reactor . It was found in the luggage of a passenger on a flight to Tehran . Iranian news media quoted an embassy official in Moscow as saying any reports that the passenger had been arrested were false . ` Russia 's atomic expert says the material is used only for scientific research .
A nuclear expert says the material can not be used for research . Russian customs agency says the radioactive material can be obtained from a nuclear reactor . It was found in the luggage of a passenger on a flight to Tehran . Russia 's atomic expert says the material is used only for scientific research .