Abstract
Neutron multiplicity analysis is a widely used technique in international safeguards and is most commonly applied to the assay of product and scrap materials in the production of mixed oxide fuel. The typical neutron multiplicity analysis applies only a crude, almost cursory, uncertainty analysis limited to propagation of statistical errors in the derived singles, doubles, and triples count rates through the point source model. While these analyses do not account for uncertainties in basic detector parameters (e.g., efficiency or gate utilization factors), nuclear data, or covariances between any of these values, measurement uncertainties are often quoted in the range of 1–2% of the resulting mass values. In this work, we examined the impact of the nuclear data and instrumentation uncertainties on the multiplicity assay result for various counting regimes using the point-model equations as the basis for discussion. Potential biases introduced by the current nuclear data set on the measurement and the need for a more complete error treatment when we progress beyond empirical calibrations based on highly representative items will be discussed.
