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

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III. OTHER HUCLEAR DATA ACTIVITY
Generation of Way Multigroup Cross Section Sot for Various
Materials for Fast Reactor Applications
(M.M.Ramnnadhan, V.Gopalakrishnan, S.Ganesan)
Using the Nuclear Data Processing Code system RAMBHA
developed at RRC, Kalpakkant, multigroup cross sections were
generated from the basic data library ENDF/B-XV for various
elements* The isotopes covered thus far Include the following:
Cr, Ni, Ha, 0, C, Al, Si, No, Mn and Ga
Ibe multigroup cross section data of these elements are considered
'improved* compared to our earlier set due to the following
improvements in the processing code system that is used for multigrouping:
1. Abandoning the resonance integral method, the infinite
dilution cross section computed using the code system
LXNEAR-MBCENT-KEX1 2 which is the most suited for ENDF/B
type of basic data representation*
2. Abandoning the J* method of Hwang, the shielded cross
sections are obtained using the code system LINEAR-RECENT-
REJC2 in the resolved resonance region.
o
3* The LXNEAR-RECEHT-RE3C1 code system also improves the
elastic removal cross section in the resonance region*
These new infinite dilution group cross sections were
compared in detail (groupwiae, reactionwise and materialwise)
with the 1969 adjusted French multigroup cross section set using
the program COMPLOT and this comparison not only brought out
the differences due to Improvement in our own processing code
system but also the significant changes in the basic cross
section data itself, thanks to improved differential data base*
The groupwise and reactionwise comparisons of these