JAEA-Conf 2011-002 - 日本原子力研究開発機構

Calculation was performed by the MVP with rigorous treatment of the core geometries and material
compositions as much as possible. The nuclear data libraries used in the MVP analyses were JENDL-4.0,
JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. These nuclear data were used to evaluate sample worth of rare-earth
elements (Dy2O3, Ho2O3, Er2O3 and Tm2O3), and the results were compared to evaluate the difference among
nuclear data libraries. A sample worth was evaluated as the multiplication factors between the cores with a
sample and without a sample. Neutron multiplication factor for each core was evaluated with 2.5 billion
histories. C/E value of sample worth is shown in Table 1 and Fig. 2.
Table1C/E value of sample worth
JAEA-Conf 2011-002
Fig. 2C/E value of sample worth
As shown in Table 1 and Fig. 2, remarkable difference in C/E values among nuclear data libraries could not
be observed for all elements and cores. However there is a relatively large difference in the C/E value of Ho2O3
at EE1 core between ENDF/B-VII.0 and JEFF-3.1. The spectrum dependency on C/E values would be in the
case of Dy2O3 calculated with ENDF/B-VII.0 and JEFF-3.1. A spectrum dependency on C/E values can be
evaluated by the comparison of C/E values at between E3 and EE1 cores. However all C/E values are roughly
around 1.0 (from 0.98 to 1.11) by considering a standard deviation of about 0.03 depicted as error bars in Fig. 2.
This fact indicates the validity of cross section data for Dy, Er, Ho and Tm in the libraries (JENDL-3.3,
JENDL-4.0, ENDF/B-VII.0 and JEFF-3.1). The next chapter describes the difference of the C/E values
between these libraries in detail by considering infinite dilution cross section for each nuclide.