Analysis of Correlated Coupling of Monte Carlo Forward and Adjoint Histories

Journal Article · Thu Feb 15 04:00:00 EST 2001 · Nuclear Science and Engineering

OSTI ID:20804691

Ueki, Taro; Hoogenboom, J E ^[1]; Kloosterman, J L ^[1]

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1. Delft University of Technology (Netherlands)

In Monte Carlo correlated coupling, forward and adjoint particle histories are initiated in exactly opposite directions at an arbitrarily placed surface between a physical source and a physical detector. It is shown that this coupling calculation can become more efficient than standard forward calculations. In many cases, the basic form of correlated coupling is less efficient than standard forward calculations. This inherent inefficiency can be overcome by applying a black absorber perturbation to either the forward or the adjoint problem and by processing the product of batch averages as one statistical entity. The usage of the black absorber is based on the invariance of the response flow integral with a material perturbation in either the physical detector side volume in the forward problem or the physical source side volume in the adjoint problem. The batch-average product processing makes use of a quadratic increase of the nonzero coupled-score probability. All the developments have been done in such a way that improved efficiency schemes available in widely distributed Monte Carlo codes can be applied to both the forward and adjoint simulations. Also, the physical meaning of the black absorber perturbation is interpreted based on surface crossing and is numerically validated. In addition, the immediate reflection at the intermediate surface with a controlled direction change is investigated within the invariance framework. This approach can be advantageous for a void streaming problem.

• OSTI ID: 20804691
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 2 Vol. 137; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COMPUTERIZED SIMULATION
COUPLING
DISTURBANCES
EFFICIENCY
MONTE CARLO METHOD
PROBABILITY
PROCESSING
RADIATION TRANSPORT
REFLECTION
SURFACES
VOIDS