Nuclear Forensics

Frequent reports of illicit trafficking in nuclear and other radioactive material demonstrate the global dimensions of the problem and the importance of building up systems to detect and prevent such undesirable incidents. Nuclear forensics – described also as "fingerprinting" nuclear and radiological material” – was born in the shadow of the cold war to detect nuclear smuggling. Since then, nuclear forensics has been contributing increasingly in the global efforts to prevent the illegal smuggling and trafficking of radiological and nuclear materials, which have potential for application in nuclear terrorism.

The materials confiscated are generally intended: for industrial and medical use, for nuclear fuel cycle operations, in dangerous weapons-usable nuclear materials such as plutonium and highly enriched uranium and for use as an additive in conventional explosives (Radiological Dispersal Devices, RDDs or dirty bombs). A major focus of nuclear forensics is identifying specific signatures, which are the physical, chemical, and isotopic characteristics that distinguish one nuclear or radiological material from another. Members of public need to be made aware of such possibilities to avoid panic under such situations.

The technique draws upon sophisticated instruments and methods to analyze the nature, use, and origin of the materials. Well established techniques are now available for detection and measurement of radioactivity in low levels. Analytical methods employed include electron microscopy, x-ray diffraction, mass spectrometry, gamma and alpha spectrometry and low-level radioactivity measurements systems.

The report of such an analysis of the seized materials is used as evidence by law enforcement agencies for prosecution of criminal cases. Nuclear forensics and attribution go beyond determining the physical, chemical, and isotopic characteristics of intercepted nuclear or radiological materials. The authorities need to know the points of origin of the materials, routes of transit and the final intended destination.

The common nuclear material intercepted is uranium concentrate (yellow cake). The yellow cake is the product from uranium mining/milling operations, and the uranium involved is generally of natural origin, which is considerably less hazardous (of low specific activity) than the uranium from the enrichment cycle. Alternatively, other materials involved in such illicit trafficking could well be commercial radioactive source materials such as cesium-137, strontium-90, cobalt-60, or americium-241. These isotopes are used in applications such as medical diagnostics, nondestructive analysis, food sterilization, and thermoelectric generators.

Expertize in the field of nuclear forensics is available in national atomic energy establishments and with international oragnizations such as International Atomic Energy Agency (IAEA), Vienna.