Design and Analysis of an Internal Remote Monitoring System for Spent Nuclear Fuel Stored in a Dry Cask

Until a long-term solution is finalized, interim storage of sufficiently cooled spent nuclear fuel (SNF) assemblies in dry casks is the predominant practice. Since these dry casks can contain approximately 160 kg of reactor-grade plutonium, they require safeguards monitoring. Results of a simulation study conducted on the design development and analysis of a remote monitoring system (RMS) are presented. The goal of the study was to determine the suitability of this RMS to meet the SNF monitoring objectives. MCNP simulations of a dry cask with all its contents and a set of simulations with one or two removed SNF assemblies were performed to test the detection capabilities of the RMS. The removed assemblies were substituted with dummy assemblies to simulate concealment. The studies showed that the RMS design is suitable to monitor and detect the removal of even a single SNF assembly from the cask.