Delayed neutron activation analysis for safeguards

Abstract

Delayed neutron activation analysis (DNAA) presents a fast, accurate, and reliable method for quantification of fissile material. The method has relatively few sources of error and may be accomplished nondestructively. The need for a fast, accurate screening of materials stems from the necessity to protect cleanroom facilities from widely varying fissile quantities in samples and from desired gains in efficiency of mass spectrometric analysis by assisting in spike level selection and by removing from the sample set those materials that are not of interest. During the last several years, many different materials have been screened or analyzed in support of international safeguards, internal process control for actinide separations, and in uranium contamination assessments. Swipes from a variety of sources have been analyzed, either before or after dissolution, and comparison of the DNAA results to mass spectrometry results is generally favorable. A facility characterization of the High Flux Isotope Reactor was performed using filter paper swipes to demonstrate the utility of the DNAA technique.