MCNP perturbation corrections for k{sub eff} estimators

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Transactions of the American Nuclear Society

OSTI ID:552474

Densmore, J D; Hendricks, J S; McKinney, G W ^[1]

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1. Los Alamos National Lab., NM (United States)

Perturbation techniques are powerful tools for determining the effects of small changes, or perturbations, to a problem. The recently released MCNP4B Monte Carlo computer code uses the differential operator technique to calculate changes in tallies caused by perturbations in density and composition for given energy ranges and reaction types. The differential operator is approximated by a second-order Taylor series. The implementation of the Taylor series assumes that the tallies are independent of any perturbed cross sections. However, if the tally involves a cross-section multiplier that is perturbed, this assumption is invalid, and incorrect results will be generated. To correct for this assumption, an additional term must be added to the perturbation that will account for the dependence of tallies on perturbed cross-section data.

• OSTI ID: 552474
• Report Number(s): CONF-971125--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 77; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACCURACY
CROSS SECTIONS
DISTURBANCES
M CODES
MULTIPLICATION FACTORS