Year
2013
Abstract
A study is in progress at Texas A&M University on the computational and experimental methods for determining the feasibility of reliably predicting and measuring unique intrinsic physical signatures in separated weapons-grade plutonium produced by certain reactors, specifically a Fast Breeder Reactor (FBR) and CANDU-type (CANada Deuterium Uranium) thermal reactor. These reactor types will likely be operating in a non-safeguarded manner in some countries. Both the FBR and the CANDU reactor fuels could produce weapons-grade plutonium when discharged at low burnup of about 1000 MWd/MTU. However, the neutron energy spectrum differences in these reactors shall result in variations in isotopes of plutonium, minor actinides and fission products. This paper presents the modeling efforts and analysis of the FBR and a separate paper is submitted in this meeting’s proceedings on the CANDU reactor modeling and analysis. The FBR core modeling and burnup cycle evaluations are completed using MCNPX-2.7 radiation transport code. Estimations of the isotopics of actinides and trace elements in the low burnt discharged radial blanket fuel assemblies are made. Characteristics that are used when selecting the isotope for signatures includes the amount of production, half-lives, Plutonium Uranium Recovery by EXtraction (PUREX) decontamination factor, and the probability of detection. Selected ratios of fission products and actinides to the 239Pu produced in the radial blanket fuel of the FBR were estimated for comparing these ratios with that of the CANDU reactor low burnt discharged fuel. Normalizing the isotopes of interest to the amount of 239Pu is found to be suitable for the PuFF project. The goal is, if smuggled weapons-grade plutonium is caught, analysis of intrinsic isotope signatures associated with it should be able to ascertain the type of reactor that produced it.