Deployment of a 7 MeV Mobile Photofission Inspection System at the Rijeka Seaport for the Detection of SNM in Cargo Containers

Special Nuclear Material (SNM) such as uranium and plutonium isotopes could be potentially involved in a terrorist attack. To prevent illicit trafficking of SNM in Europe, inspection of cargo containers at borders is required. X-ray scanning is widely used by customs to control containers. However, the latter technology is not adapted for the detection of SNM. Therefore, a second line technology based on the photofission reaction could enable to detect SNM in a non-destructive manner. In the frame of the ENTRANCE European project, the CEA-List institute and Smiths Detection have developed an Active Photon Interrogation (API) system based on a 7 MeV X-ray scanner for the detection of SNM. The system is based on the use of a linear electron accelerator (linac). First, high-energy photons generated by Bremsstrahlung in the conversion target of the linac irradiate a suspect area of the cargo container. Secondly, if SNM is present, delayed particles emitted following photofission reactions are detected. In this paper, first, we give an overview of the global scenario of the ENTRANCE project. Then, we present the field tests of the project conducted at the Skrljevo inland terminal, which is owned by the port of Rijeka, Croatia, using a 7 MeV mobile photofission system. Finally, we demonstrate the feasibility of photofission at 7 MeV using samples of depleted uranium. Further, the deployment of mobile photofission systems would make it possible to strengthen security at Europe’s borders with regard to the SNM risk.