T. Coles “Computational Nuclear Forensics Analysis of Weapons-Grade Plutonium Separated from Fuel Irradiated in a Thermal Reactor”, M.S. Thesis, Nuclear Engineering, Texas A&M University, College Station, TX (2014).
The objective of this thesis work is to utilize computational models to reliably predict the unique intrinsic signature of the weapons-grade plutonium separated from a PHWR, specifically an Indian 220 MWe PHWR. The PHWR will produce weapons-grade plutonium due to the low-burnup seen by the fuel in the computational model. MCNPX-2.7 will perform burnup calculations for the PHWR in able to determine the resulting isotopic makeup of actinides and trace elements found in the discharged fuel. The discharged fuel of interest was a single bundle of natural uranium fuel which saw a burnup of about 1 GWd/tU. The specific fission products and actinides selected for this analysis were chosen based upon five parameters; the amount of production, half-life, activity, probability of detection, and the PUREX decontamination factor. An uncertainty analysis associated with Monte Carlo methodology was completed to predict the mean and standard deviation of the amount of production from the PHWR. Ratios of the selected isotopes concentrations and activities per 1 Kg of total plutonium with a decontamination factor of 106 were calculated for the PHWR. A ratio of the PHWR results to FBR results was completed to determine if noticeable differences could be seen between the two reactor types, hence, proving the existence of unique intrinsic physical signatures in separated weapons-grade plutonium produced by differing reactor types.