ERROR PROPAGATION FOR GAMMA-SPECTROSCOPY AND NEUTRON COINCIDENCE COUNTING FOR PLUTONIUM-BEARING MATERIALS

The error characteristics of both high-resolution gamma spectroscopy a nd high-level neutron coincidence (HLNC) measurements, separate or com bined, are discussed as they apply to nondestructive analysis of pluto nium-bearing materials. Expressions have been derived to estimate the overall variance in the Pu-240 effective mass and in the total plutoni um mass in terms of the specific contributions from uncertainties in t he measurements, the pertinent physical variables (including isotopics and impurities), and the instrumental constants. Experimental data av ailable in the published literature have been used to illustrate the e rror characteristics of the HLNC and the effects of isotopic error cor relations associated with materials having different burnups.