Year
1998
Abstract
Measurements were performed with four high-enriched uranium metal annular castings with different enrichments to investigate the use of the 252Cf –source-driven noise analysis measurements as a means to quantify the amount of special nuclear material (SNM) in the casting. The noise analysis method consists of measuring the equivalent of the onedetector Rossi-a measurement, the two-detector Rossi-a measurement, and the randomly pulsed neutron measurement simultaneously in either the time or frequency domains. These measurements were performed using the Nuclear Weapons Identification System (NWIS) processor. The results of the measurements demonstrated that many of the measured parameters are sensitive to fissile mass. The detector-detector cross spectra are a factor of two more sensitive to fissile mass than the detector auto spectra or the source-detector cross spectra. The frequency spectra also have increased sensitivity over the moments of the count distributions. These measurements were with a very limited number of uranium metal castings and were the first attempt to evaluate this as a method for NDA of the uranium metal casting