The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant \# BRBAA08-C-2-0130 and \# HDTRA1-13-1-0025, the U.S. Nuclear Regulatory Commission Faculty Development Program under contract \# NRC-38-08-950, and U.S. Department of Energy (DOE) Nuclear Energy University Program (NEUP) Grant \# DE-NE0000325.