This research is concerned with non-destructive assay techniques for fissile material determination in waste material mainly in waste drums. Fissile material has been determined by active neutron interrogation with an Sb-Be neutron source which required shieldings due to the approx. 2 E12 Bq Sb-124 and had detection limits between 1 mg and 1 g fissionable material depending on sample size and matrix composition.
Neutron transport calculations at SCK/CEN Mol are intended to achieve a theoretical understanding and an improvement of the assay system with different neutron sources by modelling the neutron transport properties in the waste drum and the assay system. A replacement of the Sb-Be neutron source by other low energy neutron sources, such as Am-Li, will lead to an assay system with minimum shielding requirements and constant source strength. The replacement of the Sb-Be neutron source by Am-Li is therefore an important objective of this research. The aim of the final assay system is an easy-to-use and reliable instrument for the estimation or determination of the fissile material content of various packages, mainly waste drums.
Checking and optimization of the Sb-Be system by comparison with neutron transport calculations.
Active neutron interrogation with other neutron sources, in particular Am-Li and comparison with neutron transport calculations.
Modification of the system for passive neutron counting capabilities.
Test and performance of the active/passive neutron assay system with actual samples, mainly waste drums from the nuclear fuel cycle.
Funding SchemeCSC - Cost-sharing contracts