RECENT DEVELOPMENTS IN ACTIVE NEUTRON INTERROGATION OF ‘5U BY COMBINED TRANSMISSION AND EMISSION MEASUREMENTS.

This paper describes an active neutron interrogation device fbr the assay of fissile material based on the combination of neutron emission and transmission signals. The latter enables characterisation of samples with respect to moderation and absorption. This technique allows the determination of fissile mass without prior knowledge of the sample’s characteristics, e.g. enrichment, density and moisture content. The technique has been demonstrated on LEU aud HEU standards tlom the Performance testing LAboratory (PERLA) at the JRC Ispra and was tested on scrap material originating ftom a HEU reprocessing facility.