Results from the third Galaxy Serpent tabletop exercise demonstrating the utility of nuclear forensics libraries in support of an investigation

Galaxy Serpent is a virtual, web-based international ongoing series of tabletop exercises designed to mature the concept of National Nuclear Forensics Libraries (NNFL) and illustrate their utility in answering investigative questions or providing investigative leads as part of an investigation involving nuclear or other radioactive material (R/N) out of regulatory control (MORC). Two prior versions of the exercise have been conducted; the first utilizing surrogate data for spent nuclear fuel as the material of interest, and the second using synthetic sealed radioactive source data. Teams participating in the recently concluded third version of the exercise were provided with synthetic uranium ore concentrate (UOC) data mimicking actual data characteristics (e.g. trace element concentrations), which was used to compile a model NNFL. Teams decided how to organize and interpret the data they were provided, dealt with real world features such as missing data, and assessed discriminating attributes. Next, a hypothetical scenario involving three UOC samples found out of regulatory control was provided, and each team had to assess the self-consistency of the individual sources in the unknown data, and employ their model NNFL as a comparative assessment instrument to determine whether the three UOC materials in question were consistent with any of the types of materials in their library. The design of the exercise, methodologies utilized by participating teams, and aggregate results of the exercise will be presented, along with challenges encountered and benefits realized.