TEST 10 -- TRX-1 REGIONS 0 5 0 1 2 1 0 3 0 0 69 2 96 20 40 3 3 5 4 3 FUEL CLAD MOD FUEL 300 .75892 3 1.15 1.15/ CLAD 300 .280851 -3/ MOD 300 1.78489 -3/ 1 1 U235 6.253E-4 FREE/ 1 1 U238 4.7205E-2 FREE/ 2 2 AL27 5.1728E-2 FREE/ 3 3 H1 6.676E-2 H20/ 3 3 016 3.338E-2 FREE/ CHI F238 F235 C238 2 NFTOT 1 U238 3 NFTOT 1 U235 4 NG 1 U238 STOPThe TRX-1 thermal benchmark (Ref. 23) is a hexagonal lattice of aluminium-clad pins of enriched-uranium in water. The heterogeneity option
IHET=3 is used to compute the
Dancoff corrections for an infinite hexagonal lattice. A 69-group
library is used because it contains thermal scattering matrices.
Note that free gas scattering is called up for most of the
materials, but the cross sections for hydrogen in water are used
for H1. Using 40 thermal groups gives a cutoff at 2.60
eV. Upscatter is limited to 20 groups; any larger energy gains
would be truncated so as to preserve the scattering
cross-section. The table length is 20+69+3+4, so all downscatter
groups will be kept.
The output P1 cross sections are written in group ordering on
a file in GOXS format, which can be read directly by the ONEDANT
SN code if its name is changed to MACRXS. Another
copy of this file must also be made with the name SNXEDT
for use by the ONEDANT edit module. The ONEDANT input for this
case follows:
1
TRX-1 INFINITE LATTICE CELL - 69 GROUPS - ENDF/B-VI
DIMENS= 2 69 8 3 3 3 4 40 T
XMESH= 0. .4915 .5042 .5753 .9482 XINTS= 17 3 3 17
ZONES= 1 0 2 3 T
LIB= MACRXS T
ASSIGN= MATLS T
SOLIN= 1 1 0 0 3 SOLOUT= 1 0 0 0 0 0 0 1 NORM= 1. T
RZMFLX= 1 T
Note that no mixing is done in ONEDANT because the MACRXS
file already contains the appropriate macroscopic cross sections
for the two regions. The two key statements are
LIB=MACRXS and ASSIGN=MATLS. When the flux
calculation is complete, ONEDANT writes a flux file that can be
used as input to a second TRANSX run. The RZMFLX file
is a nonstandard CCCC file for Regular Zone
Moments FLuX .