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Determination of Fissile Material by Neutron Transport Interrogation


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.

Work programme:

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.


Forschungszentrum Jülich GmbH
52428 Jülich

Participants (1)

200,Herrmann Debrouxlaan 40-42
1160 Bruxelles