The random measurement errors associated with plutonium assay methods for mixed oxide pellets were determined from 36 samples. The methods studied were controlled potential coulometric and five variations of two nondestructive assay techniques (gamma and neutron counting). It was shown that minimum measurement errors for a single determination of 0.21% relative were obtained by controlled potential coulometric for Pu/M02 while errors were on the order of 0.8% relative for gamma counting and 1 to 2t% relative for neutron counting. The total measurement error including variation in sampling was estimated to be 0.28% relative. A bias in the controlled potential coulometer results of 0.015% relative was also observed in the determination of paired pellets analyzed during two different time periods. Gamma counting was more sensitive to sample configuration than neutron counting.
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