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You Only Get One Chance: Nuclear Forensics in Action

1 July 2014
Nuclear forensics is an important tool in the fight against illicit trafficking of nuclear and other radioactive material and assists authorities if a law has been broken.  Such materials are commonplace in energy, medicine, industry and research, but if they go out of regulatory control, a State must be ready to respond. The IAEA's Division of Nuclear Security, together with the US National Nuclear Security Administration (NNSA), recently conducted an "International Nuclear Forensics Methodologies" training course at Pacific Northwest National Laboratory (PNNL) for 26 experts from 10 Member States to learn about the specialized nature of nuclear forensics.What material is it? Does it pose a threat? Who is responsible for the loss? Where did the material originate? Have national laws been broken?  To understand these questions, participants took part in scenario-based exercises that illustrated the importance of understanding nuclear forensic investigations as part of responding to a nuclear security incident.  From the crime scene to the courtroom, it is critical that no mistake is made that could compromise an investigation, including receipt, handling and inventory of forensic evidence.  A nuclear forensic investigation must be methodical, because unless conclusions can be verified in a laboratory, they cannot be used in a court of law nor withstand prosecutorial scrutiny.  You only get one chance.Border control officers are at high alert.  A truck manifest says that it is carrying fertilizer. But a neutron alarm suggests it is a suspect vehicle.  Participants must verify the alarm and contact authorities. They use handheld radiation detection equipment to locate and identify a source, which turns out to be Barium-133.  A decayed source such as this is acceptable to transport, but participants know not to expect neutrons from Barium-133.By providing clues to where and when illicit materials were manufactured as well as potential points of diversion and trafficking routes, nuclear forensics allows States to make informed decisions about improvements to their nuclear security regimes and supports investigations of unauthorized acts. By incorporating nuclear forensics as a means to strengthen their national nuclear security regimes, the IAEA assists States to move from vulnerability to capability. Hands-on training is essential to these efforts.Awareness and understanding of the elements of proper sequencing of a nuclear forensics examination, including the gathering of evidence utilizing a chain of custody, and sequenced analysis in a laboratory equipped and authorized to analyse nuclear and other radioactive material are essential.  Technical capabilities already maintained by a State, such as analytical laboratories established within research institutes or radiation measurement instrumentation used for environmental monitoring, may also be applied to nuclear forensic examinations along with trained personnel, documented procedures and the use of calibrated equipment and standards.Radiological crime scene management requires ensuring appropriate measures are taken to ensure the integrity of evidence.  This includes setting up a perimeter, rendering the area safe, and making sure there is no device that can explode.  Participants were introduced to this concept to better understand the importance of communication between agencies including law enforcement, radiation protection and competent national authorities.Once material is submitted to the lab for forensics examination, participants are required to give consideration to personal protection equipment including lab coats, gloves and safety glasses.  Here they learn that continuity of evidence is important to ensure a chain of custody.  It accounts for movement of the evidence to demonstrate that it has stayed within authorized control.In the lab, participants apply security seals to boxes containing evidence.  Such measures, part of a chain of custody, ensure that no unauthorized access has occurred and that the evidence has not been compromised.The IAEA's Incident and Trafficking Database (ITDB) has received reports of nearly 2400 incidents of illicit trafficking and other unauthorized activities involving nuclear and other radioactive material since 1995. This underscores the vulnerabilities that persist, and that States require effective tools to combat future incidents.  Nuclear forensics enables States to connect the dots by providing quantitative information helping to link people, places, things and events.Participants use a balance to measure the weight in addition to determining the sample's mass, density and dimensions.  Characterization is a detailed analysis of the material that only takes place in the lab itself.  It helps to determine whether the material is consistent with the material used, produced or stored within a given state.Traditional forensics, which examines physical, biological, behavioural and documentary evidence, utilizes photography to record information. Rulers and colour charts are incorporated into material analysis, bridging traditional forensics and nuclear forensics.  The set-up to ensure that evidence is not contaminated requires careful preparation and inclusion of many such component parts.A package from the crime scene comes into the lab and is unpacked in a glove box, a sealed enclosure operated at negative pressure to ensure users are not contaminated by radioactive material.  As records for the court, participants take notes of each stage of the unpacking, which have to be detailed and accurate.Alpha spectrometry, an analytical technique that can detect alpha particles emitted from uranium and plutonium, can be used to characterize a seized sample of nuclear material.  Participants undertake simulation of a destructive separation technique that isolates the uranium and plutonium by dissolving the sample in acid in a powder form, then chemically separating it, to produce a sample which can be prepared for counting by alpha spectrometry.Once the powder is dissolved, participants use a vacuum pump for filtration of the sample.  Each step brings them closer to getting an alpha spectrum, which can be interpreted for nuclear forensics findings. If one can identify the material's origin and compare analytical information with a State's own data, the significance is far-reaching - this can support prosecution, help to identify nuclear security vulnerabilities and strengthen a State's overall national nuclear security regime.Nuclear forensics utilizes measurements of isotopes, chemical elements and physical characteristics of nuclear and other radioactive material, along with associated traditional or non-nuclear evidence - hair, fibres, fingerprints, tool marks, DNA, explosive residues, digital evidence, among others - to determine material origin and history. Analysis of seized radioactive materials allows two unique incidents to be compared quantitatively.  Understanding the need for precision measurements is critical to the nuclear forensics process.The sharing of expertise amongst scientific peers in a national lab such as PNNL was a unique aspect of this course.  International nuclear forensic partnerships are essential to strengthening nuclear security worldwide.Precise analysis is essential.  PNNL staff show participants instrument specifications on a pressure gauge as part of their hands-on training.Participants use separation columns to simulate the isolation of a single radionuclide of interest.With a sub-sample, participants use techniques like filtration and separation.  The sample is then analysed to identify alpha-emitting radionuclides.  Participants discuss instrument specifications and limitations, and using commercially available spectrum-analysis software, assess the composition of the sample.  Peak energies are compared to a database of materials/radionuclides to enable identification and, ultimately, a nuclear forensics finding.The responsibility for establishing and maintaining nuclear forensics capability rests with each State. But there is no barrier to entry. The IAEA, upon request, provides assistance to States by developing and publishing guidance, delivering introductory and applied training, capacity building through provision of experts and access to leading international laboratories, and partnerships with key institutes in nuclear forensics like PNNL and those others maintained by NNSA.

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