William Charlton
Associate Professor
Department of Nuclear Engineering
Texas A&M University
''Nuclear Forensics: Identifying the Actors Involved
in an RDD Incident"
Abstract:
If a radiological dispersal device (RDD) is
detonated in the U.S. or near U.S. interests overseas, it will be
crucial that the actors involved in the event can be identified quickly.
Law enforcement officials will need information concerning the material
used in the device, specifically what type of material it was and
from where it originated. This information will then be used to help
identify the specific individuals who manufactured the device and
perpetrated the event. Texas A&M University and Los Alamos National
Laboratory are collaborating on the development of a technique for
identifying the material used in a radiological dispersal device.
This methodology is currently focused on radiological dispersal devices
that make use of spent nuclear fuel as the source material. The methodology
developed makes use of both a forward model and an inverse model to
identify specific spent fuel characteristics using isotopic composition
of RDD debris. The forward model is based on sophisticated reactor
physics calculations for the prediction of spent fuel isotopic compositions
as a function of fuel type (e.g., PWR, CANDU, RBMK, etc.), fuel burnup,
fuel age (in years since permanent discharge from the reactor), and
operating characteristics (e.g., operating power level, time at power,
etc.). These reactor physics calculations are benchmarked to measured
data to establish their accuracy in predicting isotopic compositions.
The inverse model makes use of a Bayesian inverse method to identify
the specific spent fuel assembly (or assemblies) used based on measurements
of actinide and fission product isotopic ratios in the RDD debris.
A description of both the forward and inverse models, accuracies of
the technique, and the results to date will be given.