INDC(IND)-35G - IAEA Nuclear Data Services

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The Program 'REX1 for Accurate Generation of Multigroup Infinite
Dilution Cross Sections. Elastic and Inelastic Transfer Matrices
and the Program 'RBX2* for Accurate Calculation of Self Shielding
Factors in the Resolved Resonance Region for Fast Reactor Applications
(V.Gopalakrishnan and S.Ganesan)
1 2
The computer programs REX1 and REX2 are two parts of
RAMBHA , a nuclear data processing code system for fast reactor
applications, developed at RRC to obtain multigroup cross
u
section data using the basio library in the ENDF/B-TV format.
REX1: This program is intended for multigrouping point data
available in the ENDF/B-IV format* The program expects the
cross sections to be directly specified as point data without
parameterization through resonance formalisms. If the actual
cross sections are represented by a combination of resonance
parameters and floor corrections in some energy region and as
point data in other energy regions, then, one has to use the
preprocessing codes LINEAR -RECENT before using REX1 for multigrouping.
In addition to group cross sections, the program
calculates the multigroup transfer matrices for elastic
scattering by Bucholz' method and the multigroup transfer
matrices for inelastic scattering by the method followed in
MIGROS-3 8 .
The program follows any interpolation scheme specified
according to ENDF/B-XV conventions and uses Gauss' quadrature
whenever numerical integrations are needed. Standard fast
reactor flux spectra expressed in a functional form in various
energy regions are utilised for weighting.
REX2: The resolved resonance has been extended considerably
for many isotopes of interest in reactor design by means of high
resolution cross section measurements. The improved quality of
data in the resonance region hes called for faithful multi-