Application of Polynomial Chaos Expansion in One-Dimensional Inverse Transport Problems

Journal Article · Sat Jul 01 04:00:00 EDT 2017 · Transactions of the American Nuclear Society

OSTI ID:23047490

Bledsoe, Keith C.; Jessee, Matthew A.; Lefebvre, Jordan P. ^[1]

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1. Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)

In the problem of inverse radiation transport, measurements of particle leakages from radioactive source/shield systems are used to infer unknown parameters within the systems. This reconstruction can be accomplished by finding the physical parameters of the unknown system that minimize the difference between calculated detector responses and measured detector responses. The inverse transport solver should also propagate uncertainties from the detector responses to the reconstructed parameter values. Recently, the Differential Evolution Adaptive Metropolis (DREAM) method was shown to be a robust method for uncertainty quantification in inverse problems. The DREAM method uses the differential evolution algorithm to choose efficient steps in a Markov chain Monte Carlo (MCMC) simulation. Although the DREAM method has been shown to be more efficient than traditional MCMC approaches, it still requires thousands of transport computations to accurately quantify uncertainty. For the simple ray-tracing model, it was possible to perform these calculations in a reasonable amount of time (under an hour). However, inverse transport problems that require computationally-intensive transport solvers will need prohibitively long run times when using the DREAM method. A way to overcome the computational burden of the DREAM method is to perform surrogate modeling using the polynomial chaos expansion (PCE) approach. It was recently shown that the PCE method provides both accurate and computationally inexpensive uncertainty quantification in forward radiation source/shield problems. PCE was also recently applied to an inverse problem in nonlinear point reactor kinetics within a standard MCMC approach. PCE was first used with the DREAM method where it was applied to inverse problems in groundwater modeling.

• OSTI ID: 23047490
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 116; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICS AND COMPUTING
ALGORITHMS
CHAOS THEORY
COMPUTERIZED SIMULATION
GROUND WATER
MARKOV PROCESS
MONTE CARLO METHOD
ONE-DIMENSIONAL CALCULATIONS
PARTICLES
POLYNOMIALS
RADIATION SOURCES
RADIATION TRANSPORT
REACTOR KINETICS
SHIELDS