J.M. Osborn, S.S. Chirayath, and W.S. Charlton,
"Neutronics Analysis of Fast Breeder Reactor Core to Support the Plutonium Fingerprinting for Forensics (PuFF) Project,"
INMM 54th Annual Meeting, 14-18 July 2013, Palm Desert, California, USA.
One of the objectives of this project is to use
computational and experimental methods to determine the feasibility
of reliably predicting and measuring a unique intrinsic physical
signature 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 produce
weapons-grade plutonium when burned to low burnups 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. The computational part of the
project utilizes MCNPX-2.7 radiation transport code to model the
reactor core, perform burnup cycles and estimate the resulting
isotopics of actinides and trace elements in the discharged fuel.
Characteristics that were evaluated when selecting the isotope
signatures included the amount of production, half-lives, Plutonium
URanium EXtraction (PUREX) decontamination factor, and the
probability of detection. Results of the ratios of each selected
fission product and actinide to the 239Pu produced in the fuel
showed significant differences between the FBR and CANDU.
Normalizing the isotopes of interest to the amount of 239Pu is
suitable for the PuFF project because this aids in evaluating
separated weapons-grade plutonium. 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. Fuel samples will be irradiated with a
replicated neutron spectrum at the Oak Ridge National Lab-High Flux
Isotope Reactor (ORNL-HFIR), and then subject to a lab scale PUREX
process to separate plutonium from fission products and uranium.
Specific plutonium isotopes and fission products retrieved from the
simulation results were investigated for correlations and will be
compared with the experimental data when they become available in
the latter half of this investigation. A separate abstract is
submitted for the CANDU side of the PuFF project.
Associated Project(s):Plutonium Fingerprinting for Forensics (PuFF) Project