Stand-Off Neutron Detection Monitoring of the Movement of Spent Nuclear Fuel

It is currently a priority objective of the Department of Safeguards within the International Atomic Energy Agency (IAEA) to “strengthen instrumentation capabilities for verification”, with the specific research and development need to “develop safeguards equipment to establish and maintain knowledge of spent fuel in shielding/storage/transport containers at all points in their life cycle” [1]. This presentation demonstrates the use of a large-area (~0.2 m2) neutron detector to monitor the movement of spent nuclear fuel at facilities of Canadian Nuclear Laboratories, at stand-off distances of up to 100 m, even in the presence of significant shielding and infrastructure. In particular, the on-line re-fueling activities at the National Research Universal (NRU) research reactor have been monitored outside of the reactor building, at a distance of 69 m from the reactor core. Further, the movement of legacy spent nuclear fuel at the Fuel Packaging and Storage (FPS) facility, for the purpose of improving the storage of select legacy spent nuclear fuel rods, has been monitored with the same neutron detection technology at similar stand-off distances, even while the spent fuel is kept inside heavy shielding during the movement. Each of the measurement scenarios at NRU and FPS can likely be enhanced through simultaneous monitoring by a coordinated network of sensitive, large-area neutron detectors, which is practical by virtue of the economy of scale of the neutron detectors employed. The scope of potential for this measurement technique for verification and maintaining continuity of knowledge of spent fuel in shielding, storage, and transport, will be discussed.References[1] IAEA Department of Safeguards, Development and Implementation Support Programme for Nuclear Verification, STR-386, Vienna, Austria, 2018 January.