Necessity (proposal) of secure detection system of nuclear materials and interior inspection systems of detected / suspicious objects in non-destructive manner for safe dismantling

Large size freight cargo containers are the most vulnerable items from nuclear security points of view because of their large volume and weight of cargo inside for hiding heavily shielded objects. For strengthening nuclear security, secure detection of NMs in heavily shielded objects, and safe handling (dismantlement) of detected / suspicious objects for taking out of NMs, are essential. These require the following things, 1. Introduction of secure detection system of NMs, 2. Inspection of detailed and interior structures of detected objects, 3. Rough characterization of NMs (for nuclear bomb or RDD etc.) / Confirmation of existence of explosives etc.. By using information obtained by interior inspections, safe dismantlement of objects and taking NMs out are possible. In this paper, we propose a combined system of X-ray scanning system with NRF-based NDD system using monochromatic gamma-ray beam not only as a secure detection system of NMs but also interior inspection system (covering 1. and 2.). Also we propose active neutron NDA system using a D-T source for interior inspection of NM part (covering 3.). (author)