JAEA-Data/Code 2007-004 - Welcome to Research Group for ...

this tag appears to denote the nearest temperature point to the material temperature
as the 8-th character of the member for the effective microscopic cross-sections on
MICREF file.
2 IRES Resonance cross-section process indicator.
= 0 Non resonant nuclide (or minor resonant nuclide whose heterogeneity is
negligible)
To the resonant nuclide that has f-table based on the NR
approximation, the interpolation of self-shielding factor will be done
although the heterogeneous term g(C)(1-C)/(N n l) to evaluate the
background cross-section σ 0
is not considered (C=1). The σ 0
is
calculated for the homogenized system, if there is no resonant nuclide
with IRES=2 in the material.
The IR approximation is not applied to this nuclide even if the
resonance level parameters are installed.
= 1 Effective microscopic cross-sections, which have been calculated in the
previous case, will be read from MICREF file as if this nuclide is
non-resonant. (IRES=2, if double heterogeneity is considered) The
member denoted by IDENT must exist on MICREF file.
= 2 Treatment as a resonant nuclide.
Effective microscopic cross-sections (before modification by IR or
PEACO) is obtained by Eq.(2.9-1) taking into account heterogeneity
effect.
If IC3=1 (Sect.2.2) is specified, the nuclide dependent Dancoff
correction factor internally calculated by the collision probability method
is used in the heterogeneous term.
= 3 Effective only PEACO routine is used and if this nuclide is a constituent
of non-resonant material. The tabulation of collision probabilities (P ij )
will be made by each fine-group (Users group structure) considering the
change of cross-section of this nuclide by group.
= 4 Effective only PEACO routine is used and if this nuclide is a constituent
of non-resonant material. Two-dimensional P ij tabulation will be made
assuming the behavior of cross-section of this nuclide as 1/υ .
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