Monte Carlo variance reduction with deterministic importance functions

Haghighat, Alireza; Wagner, John C.

doi:10.1016/s0149-1970(02)00002-1

Cited by 145 publications

(49 citation statements)

References 26 publications

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“…The CADIS method, 1,2) which is based on the recognition that the adjoint function (i.e., the solution to the adjoint Boltzmann transport equation) has physical significance as a measure of the importance of a particle to some objective function (e.g., the response of a detector), was originally developed at the Pennsylvania State University for the purpose of optimizing MC calculations of ex-core detector response in pressurized-water reactors (PWRs). 3) This method provides consistent formulations for source and transport biasing parameters and their implementation within the weight window technique.…”

Section: Consistent Adjoint Driven Importance Samplingmentioning

confidence: 99%

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

Wagner

Peplow

Mosher

et al. 2011

Progress in Nuclear Science and Technology

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This paper provides a review of the hybrid (Monte Carlo/deterministic) radiation transport methods and codes used at the Oak Ridge National Laboratory and examples of their application for increasing the efficiency of real-world, fixed-source Monte Carlo analyses. The two principal hybrid methods are (1) Consistent Adjoint Driven Importance Sampling (CADIS) for optimization of a localized detector (tally) region (e.g., flux, dose, or reaction rate at a particular location) and (2) Forward Weighted CADIS (FW-CADIS) for optimizing distributions (e.g., mesh tallies over all or part of the problem space) or multiple localized detector regions (e.g., simultaneous optimization of two or more localized tally regions). The two methods have been implemented and automated in both the MAVRIC sequence of SCALE 6 and ADVANTG, a code that works with the MCNP code. As implemented, the methods utilize the results of approximate, fast-running 3-D discrete ordinates transport calculations (with the Denovo code) to generate consistent space-and energy-dependent source and transport (weight windows) biasing parameters. These methods and codes have been applied to many relevant and challenging problems, including calculations of PWR ex-core thermal detector response, dose rates throughout an entire PWR facility, site boundary dose from arrays of commercial spent fuel storage casks, radiation fields for criticality accident alarm system placement, and detector response for special nuclear material detection scenarios and nuclear well-logging tools. Substantial computational speed-ups, generally O(10 2-4 ), have been realized for all applications to date. This paper provides a brief review of the methods, their implementation, results of their application, and current development activities, as well as a considerable list of references for readers seeking more information about the methods and/or their applications.

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Section: Consistent Adjoint Driven Importance Samplingmentioning

confidence: 99%

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

Wagner

Peplow

Mosher

et al. 2011

Progress in Nuclear Science and Technology

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“…It is possible to install 14 bundles of pressurized water reactor spent-fuel assemblies. [17][18] Figure 3 also shows the source region for the calculation of the adjoint flux. Since the source intensity of neutrons in a spent fuel assembly depends strongly on the specific burn-up distribution in the axial direction, the burn-up distribution was taken into account in the present calculation.…”

Section: Validation Of Smire Systemmentioning

confidence: 99%

“…The effective multiplication factor, , of the cask containing 14 PWR assemblies was calculated by the KENO Fuel effective region Fig. 3 Calculation geometry of the transport cask and adjoint source region [17][18] VOL. 2, OCTOBER 2011…”

Section: Validation Of Smire Systemmentioning

confidence: 99%

Monte Carlo Shielding Calculations for a Spent Fuel Transport Cask with Automated Monte Carlo Variance Reduction

Asami

Sawamura²,

Nishimura³

2011

Progress in Nuclear Science and Technology

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For the purpose of performing reasonable shielding calculation of a spent fuel transport cask, the use of Monte Carlo methods has been proposed for solving the radiation transport problem on a detailed structure of the transport cask considering fixed neutron sources. A SMIRE (Simplified MCNP-ANISN_W Variance Reduction) system has been developed in the present study, which is possible to generate automatically the lower weight boundary of the weight window for each mesh based on the Consistent Adjoint Driven Importance Sampling (CADIS). Compared with the case of the importance based on the empirical formula, the figure of merit is increased by a factor of 25. In this system, it is possible to calculate the weight suitable for the distantly-positioned detector point from the fuel effective region to introduce the relaxation factor which relaxes the increase of the particle numbers at the boundary of weight window meshes that are generally caused by the large attenuation of adjoint flux. This system is used for a variety of the radiation transport problems as well as the transport cask.

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“…The CADIS (Consistent Adjoint Driven Importance Sampling) methodology was developed in order to quickly and automatically determine the biased source distribution, as well as all of the values for the weight windows over a rectangular mesh and a given energy group structure (Wagner, 1997;Haghighat and Wagner, 2003). The method first determines the approximate adjoint particle flux, usually using a discrete ordinates code.…”

Section: Cadismentioning

confidence: 99%

PWR Facility Dose Modeling Using MCNP5 and the CADIS/ADVANTG Variance-Reduction Methodology

Blakeman¹,

Peplow²,

Wagner³

et al. 2007

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Monte Carlo variance reduction with deterministic importance functions

Cited by 145 publications

References 26 publications

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

Monte Carlo Shielding Calculations for a Spent Fuel Transport Cask with Automated Monte Carlo Variance Reduction

PWR Facility Dose Modeling Using MCNP5 and the CADIS/ADVANTG Variance-Reduction Methodology

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