Automatic variance reduction for three-dimensional Monte Carlo simulations by the local importance function transform -- 1: Analysis

Journal Article · Mon Sep 01 04:00:00 EDT 1997 · Nuclear Science and Engineering

DOI:https://doi.org/10.13182/NSE127-22· OSTI ID:562081

Turner, S A ^[1]; Larsen, E W ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences

A new automated variance reduction method for the Monte Carlo simulation of multigroup neutron transport source-detector problems is described. The method is based on a modified transport problem that can be solved by analog Monte Carlo with zero variance. The implementation of this modified problem is impractical, in part because it requires the exact solution of an adjoint transport problem. The new local importance function transform (LIFT) method is developed to overcome this difficulty by approximating the exact adjoint solution with a piecewise-continuous function containing parameters that are obtained from a deterministic adjoint calculation. The transport and collision processes of the transformed Monte Carlo problem bias source distribution, distance to collision, and selection of postcollision energy groups and directions. A companion paper provides numerical results that demonstrate the efficiency of the LIFT method.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 562081
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 1 Vol. 127; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ADJOINT DIFFERENCE METHOD
MONTE CARLO METHOD
MULTIGROUP THEORY
NEUTRON DETECTORS
NEUTRON SOURCES
THREE-DIMENSIONAL CALCULATIONS