R.G. McClarren, J. Madsen, M.L. Adams, M.P. Adams, N. Amato, N. Castet, S.S. Chirayath, W.D. Hawkins, L. Rauchwerger, T. Smith,
"Deterministic Transport Capability for HEU Sources in Cargo Containers,"
Poster presented at The 4th annual Domestic Nuclear Detection Office (DNDO) Academic Research Initiative (ARI) Grantees Conference, Alexandria, Virginia, April 26-28, 2011.
We have developed a deterministic transport capability based on
the discrete ordinates method (Sn) for simulating the radiation
emitted by highly-enriched uranium inside a cargo container on
large-scale parallel computing platforms. An important future
use of the method will be to produce the angular flux of radiation
that exits a container so that various detector models can be used
to assess the degree to which different detector designs perform;
this capability is not available in most Monte Carlo codes.
Our deterministic method, as implemented in the code PDT, is
competitive with standard Monte Carlo calculations in terms of
runtime, but significant improvement was needed to make accuracy
comparable between the two methods. To improve angular
accuracy we have used a recently developed quadrature technique to
allow for very large numbers of angles to be simulated (at present
we have performed calculations with 32,000 angles).
Additionally, we have implemented a high-fidelity first-collision
source/uncollided flux technique to track particles directly from
sources. We have also implemented techniques to allow for
high-fidelity treatment of radiation energy while minimizing
computational cost. These techniques allow us to refine our
energy group structure near important spectral lines and coarsen
the resolution in other energies. In the poster we present
results of calculations that demonstrate the accuracy of our
deterministic calculations using the new capabilities.
Associated Project(s):SHIELD (Smuggled HEU Interdiction through Enhanced anaLysis and Detection): A Framework for Developing Novel Detection Systems Focused on Interdicting Shielded HEU