Non-destructive nuclear forensics of radioactive samples

It is a matter of public safety and security to be able to examine suspicious packages of unknown origin. If the package is radioactive and sealed (i.e., the radioactive materials contained in the package, including their chemical and physical forms, are unknown), there is a significant risk on how to handle the package and eventually safely dispose of its contents. Within the context of nuclear security, nuclear forensics helps address the key issue of identifying the nature and origin of radioactive and nuclear material in order to improve physical protection measures and prevent future theft or diversion of these materials. Nuclear forensics utilizes analytical techniques, destructive and non-destructive, developed for applications related to nuclear fuel cycles. This paper demonstrates the non-destructive examination techniques that can be used to inspect encapsulated radioactive samples. Results of γ spectroscopy, X-ray spectroscopy, neutron imaging, neutron diffraction, and delayed neutron analysis as applied to an examination of sealed capsules containing unknown radioactive materials are presented. The paper also highlights the value of these techniques to the overall nuclear forensic investigation to determine the origin of these unknown radioactive materials. (author)