Under-Prediction of Localized Tally Uncertainties in Monte Carlo Eigenvalue Calculations

Conference · Sun Jun 26 00:00:00 EDT 2011

OSTI ID:1029579

Mervin, Mervin Brenden ^[1]; Mosher, Scott W. ^[2]; Wagner, John C. ^[2]; Maldonado, G. Ivan ^[1]

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1. University of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Modeling and simulation using Monte Carlo methods is widely used in nuclear reactor criticality benchmarking applications. However, obtaining good statistics not only takes a large amount of computational time, but it has been shown that localized tally uncertainties may be under-predicted by a factor of five or more in select cases. The primary components of this under-prediction include poor sampling due to improper source convergence and cycle-to-cycle correlations in the fission source. Additional components relate to the flux shape and the size of the tally cells. These issues must be understood and dealt with in order to support the practical use of modern Monte Carlo software packages.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1029579
• Resource Relation: Conference: 2011 American Nuclear Society Annual Meeting, Hollywood, FL, (United States), 26-30 Jun 2011
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
97 MATHEMATICS AND COMPUTING
CONVERGENCE
CRITICALITY
EIGENVALUES
FISSION
MONTE CARLO METHOD
REACTORS
SAMPLING
SHAPE
SIMULATION
STATISTICS
Nuclear Criticality Safety Program (NCSP)