ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 21 May 2007
Page Count: 10

A New Derivation of the Perturbation Operator Used in MCNP

Keith, Robert E.
Principal Scientist, ITT Industries, AES, Colorado Springs, CO

(Received 20 June 2005; accepted 26 April 2007)

Abstract

A new derivation of the perturbation operator used in the MCNP radiation transport code is presented, and equations are determined to evaluate the change in the response from a perturbation in macroscopic cross section due to the first, second, third, and fourth derivative terms, and the second-derivative cross term. The perturbation operator in MCNP currently can be used to determine the change in a response from the first and second order terms in Taylor expansion due to such a perturbation. The derivation presented here produces expressions that are equivalent to the expressions used in MCNP for the first and second derivative, but are simpler and are in a form that more readily reveals their physical significance. The perturbation operator is particularly useful for sensitivity and uncertainty analysis.

Keywords:
perturbation operator, MCNP, sensitivity analysis

Paper ID: JAI100340
DOI: 10.1520/JAI100340
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