Numerical convergence and validation of the DIMP inverse particle transport model
Abstract
The data integration with modeled predictions (DIMP) model is a promising inverse radiation transport method for solving the special nuclear material (SNM) holdup problem. Unlike previous methods, DIMP is a completely passive nondestructive assay technique that requires no initial assumptions regarding the source distribution or active measurement time. DIMP predicts the most probable source location and distribution through Bayesian inference and quasiNewtonian optimization of predicted detector responses (using the adjoint transport solution) with measured responses. DIMP performs well with forward hemispherical collimation and unshielded measurements, but several considerations are required when using narrowview collimated detectors. DIMP converged well to the correct source distribution as the number of synthetic responses increased. DIMP also performed well for the first experimental validation exercise after applying a collimation factor, and sufficiently reducing the source search volume's extent to prevent the optimizer from getting stuck in local minima. DIMP's simple point detector response function (DRF) is being improved to address coplanar false positive/negative responses, and an angular DRF is being considered for integration with the next version of DIMP to account for highly collimated responses. Overall, DIMP shows promise for solving the SNM holdup inverse problem, especially once an improved optimization algorithm is implemented.
 Authors:

 North Carolina State Univ., Raleigh, NC (United States)
 Publication Date:
 Research Org.:
 North Carolina State Univ., Raleigh, NC (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org.:
 USDOE National Nuclear Security Administration (NNSA)
 OSTI Identifier:
 1426201
 Alternate Identifier(s):
 OSTI ID: 1438026
 Grant/Contract Number:
 NA0002576; 127981
 Resource Type:
 Accepted Manuscript
 Journal Name:
 Nuclear Engineering and Technology
 Additional Journal Information:
 Journal Volume: 49; Journal Issue: 6; Journal ID: ISSN 17385733
 Publisher:
 Korean Nuclear Society
 Country of Publication:
 United States
 Language:
 English
 Subject:
 42 ENGINEERING
Citation Formats
Nelson, Noel, and Azmy, Yousry. Numerical convergence and validation of the DIMP inverse particle transport model. United States: N. p., 2017.
Web. doi:10.1016/j.net.2017.07.009.
Nelson, Noel, & Azmy, Yousry. Numerical convergence and validation of the DIMP inverse particle transport model. United States. doi:10.1016/j.net.2017.07.009.
Nelson, Noel, and Azmy, Yousry. Fri .
"Numerical convergence and validation of the DIMP inverse particle transport model". United States. doi:10.1016/j.net.2017.07.009. https://www.osti.gov/servlets/purl/1426201.
@article{osti_1426201,
title = {Numerical convergence and validation of the DIMP inverse particle transport model},
author = {Nelson, Noel and Azmy, Yousry},
abstractNote = {The data integration with modeled predictions (DIMP) model is a promising inverse radiation transport method for solving the special nuclear material (SNM) holdup problem. Unlike previous methods, DIMP is a completely passive nondestructive assay technique that requires no initial assumptions regarding the source distribution or active measurement time. DIMP predicts the most probable source location and distribution through Bayesian inference and quasiNewtonian optimization of predicted detector responses (using the adjoint transport solution) with measured responses. DIMP performs well with forward hemispherical collimation and unshielded measurements, but several considerations are required when using narrowview collimated detectors. DIMP converged well to the correct source distribution as the number of synthetic responses increased. DIMP also performed well for the first experimental validation exercise after applying a collimation factor, and sufficiently reducing the source search volume's extent to prevent the optimizer from getting stuck in local minima. DIMP's simple point detector response function (DRF) is being improved to address coplanar false positive/negative responses, and an angular DRF is being considered for integration with the next version of DIMP to account for highly collimated responses. Overall, DIMP shows promise for solving the SNM holdup inverse problem, especially once an improved optimization algorithm is implemented.},
doi = {10.1016/j.net.2017.07.009},
journal = {Nuclear Engineering and Technology},
number = 6,
volume = 49,
place = {United States},
year = {2017},
month = {9}
}