USE OF NEUTRON/GAMMA MONITORING SYSTEMS AS SAFEGUARDS USE OF NEUTRON/GAMMA MONITORING SYSTEMS AS SAFEGUARDS

Neutron/gamma monitor systems are Non Destructive Assay (NDA) systems which are being applied for safeguards purposes in a number of nuclear facilities, e.g. reprocessing plants and power reactors [1-3]. Neutrons, emitted from the irradiated fuel or from fresh Pu-containing fuel are detected together with the gamma rays. Specific patterns in the neutron/gamma rate are obtained for a number of routine operations, involving movements of nuclear materials, using such continuously operating monitor systems. Any change of the measured neutron/gamma rate will indicate movements of nuclear materials or a change in the operational status of the reactor. The neutron/gamma monitoring systems are designed to confirm the absence of nuclear materials in movements of various containers and other objects as recorded by the surveillance.