Nuclear data for nuclear material safeguards

The safeguarding of nuclear materials belongs to the most important basic functions of the International Atomic Energy Agency (IAEA). Nuclear analytical methods are being used in order to verify that nuclear materials are not diverted from declared peaceful applications. Nuclear data are important in those nuclear techniques which assay nuclear material without destroying it, i.e. non-destructive assay techniques (NDAT). One discerns passive NDAT which measure spontaneously emitted radiations, and active NDAT which measure radioactivities induced by neutron or gamma irradiation. The paper briefly outlines the NDAT currently in use or under development and the nuclear data involved in the analysis of the experimental results obtained with these techniques, and presents selected examples in more detail. (orig.)