JAEA-Conf 2011-002 - 日本原子力研究開発機構

A modified SRAC library was prepared where a correction factor 0.89 was applied to
infinite dilution capture cross of 157Gd in SRAC public thermal library prepared for the energy
range below 1.8554eV. In the preparation of the modified cross section library, total cross
sections were also adjusted corresponding to the correction of the capture cross sections,
however, the shielding factors of capture cross sections of 157Gd were not changed.
4 SRAC Burnup Calculation
Burnup calculations were performed with SRAC-Pij module using both the original
and the modified JENDL-3.3 libraries. A 2D-infinite assembly model was applied as the
burnup calculation model. Rated power histories of BWR fuel assembly were used, whose
power density, pellet/moderator temperatures and in-channel void fraction were 50.4 kW/,
520/286 and 40%, respectively. Control blade was withdrawn in all the irradiation period
and cooling period was not set up. The comparisons of neutron multiplication factors and
fission rate distributions between the burnup calculations using the modified and the original
libraries were performed and showed in Figs. 3 and 4, respectively.
JAEA-Conf 2011-002
Figure 3 Comparison of Infinite Multiplication Factors
The differences in the infinite multiplication factors of the fuel assemblies between
modified and original cross section library are 0.35%k in the UO2 fuel assembly and 0.30%k
in the MOX fuel assembly at the beginning of life (BOL), and they decrease with burnup and
finally extinguish at 15GWd/t.