Nuclear terrorism comes under spotlightListen /
The vulnerability of countries to the threat of nuclear terrorism is under the spotlight this week at the UN's International Atomic Energy Agency (IAEA).
Experts from around the world are discussing how nuclear forensic techniques can be used in the fight against illicit trafficking of nuclear and other radioactive material.
There are fears that this material can be smuggled or stolen by terrorists and used to make bombs.
Steve Thachet has been speaking to Khammar Mrabit, the Director of the IAEA's Division of Nuclear Security.
He began by asking him for a definition of nuclear forensics.