Conservation of the adjoint neutron spectrum by use of bilinear-weighted cross sections and its effect on fast reactor calculations

Journal Article · Sat Oct 01 00:00:00 EDT 1977 · Nucl. Sci. Eng.; (United States)

OSTI ID:5443546

Wade, D C; Bucher, R G

Flux weighting for the generation of broad-group cross sections is designed to preserve eigenvalue, flux spectrum, and reaction rates; however, it will not preserve adjoint spectrum and reactivity worths. Bilinear (flux-adjoint) weighting preserves all of the above quantities except reaction rates. Bilinear weighting also makes the eigenvalue of the broad-group calculation less sensitive to distortions of the spectrum away from the fundamental mode over which the cross sections were collapsed than is the case when flux weighting is used. A series of 29- and 11-group numerical tests has been made to assess the size of errors (relative to a fine-group standard) in eigenvalue, reaction rate ratios, isotopic worth components, and spectral shapes resulting from the use of the two energy collapse procedures. The errors in adjoint spectrum and calculated worth of scattering materials are found to be large when flux weighting is used.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5443546
• Journal Information: Nucl. Sci. Eng.; (United States), Vol. 64:2
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
FAST REACTORS
REACTOR KINETICS
CALCULATION METHODS
ADJOINT FLUX
GROUP CONSTANTS
MULTIGROUP THEORY
NEUTRON FLUX
CROSS SECTIONS
EPITHERMAL REACTORS
KINETICS
NEUTRON TRANSPORT THEORY
RADIATION FLUX
REACTORS
TRANSPORT THEORY
220100* - Nuclear Reactor Technology- Theory & Calculation