Triple neutron correlation for MOX waste assay

Triple neutron signal correlation techniques were applied to measure the waste in 220-l barrels. Small waste packages weighing 1 to 2 kg originating from a mixed-oxide (MOX) fuel fabrication plant were first measured in a dual range detector head by the plant operator. The correlated pair count rate of each individual package was used together with a calibration constant to determine the effective [sup 240]Pu mass equivalent. A set of such packages was then loaded into a 220-l barrel, keeping the alpha activity well below a prescribed tolerance limit. The task was to verify the [sup 240]Pu equivalent mass content in each barrel for safeguards purposes.