Gamma Ray Assay of a Waste Drum for the Determination of Plutonium Amount (III)

A waste drum was assayed in a static measurement of the set opposite to each other. The object, a 200 liter drum, is put vertically at the center, keeping a given interspace between the drum side and each detector. The system is almost minor image symmetrical. The gamma ray activity is accumulated for 3 minutes with both the detectors at the same time. The sum of both counting values. The gamma ray influence of 239Pu gamma ray. A couple of Nal (Tl) detectors are239Pu amount is estimated from the 241 system. The gamma ray attenuation of wastes is also corrected with the use of an external source of carrying 40 to 175 kg of plutonium-bearing wastes. weight can be evaluated within ± 25% error in the range of 0.02 to 10 g to a drum. Am coexisting with plutonium is eliminated in the239Pu by the137Cs. The system was applied to the assay of 86 drums239Pu