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μ
all
μ
th
C = C + C
μ
epi
, (2.10-8)
where E Cd denotes cadmium cut-off energy that can be changed by setting the group dependent
filter transmission by the user.
One pair of entries permits reaction rates of two nuclides. The spectrum indices are obtained as
ρ
28
28 28
/ th
= C epi C
25
25 25
/ all
28
28 25
/ all
* 28 25
, δ = F epi F , δ = F all F , C = C all F .
Equations (2.10-3) through (2.10-8) are calculated by the code with considering spatial
dependence and heterogeneity effect as:
/ all
IGMAX
r
ϕ ,
R
μ m g r
epi (
) = ∑ f N
μ g mσ μ
m, g Φ g (
) , (R=F or C) (2.10-9)
g= 1 ϕx,
g
where,
IGMAX
r
ϕ ,
R
μ m g r
epi (
) = ∑ (1 − f g ) N
μ mσ μ
m, g Φ g (
) , (R=F or C) (2.10-10)
σ
g= 1 ϕx,
g
μ
m, g
m, g
denotes the effective microscopic cross-section of the nuclide μ involved in the
material m of the energy group g, ϕ the local flux of the R-Region composed of the material m,
r
ϕ the average flux of x-th X-Region in the cell calculation, Φ (r)
the flux at r obtained by a
x,g
core calculation with homogenized cross-sections. The ratio ϕ m . g /ϕ x , g represents the heterogeneity
correction of local flux (disadvantage factor).
g
(d) Ratio of volume integrated reaction rates (only in CITATION)
r
r
R = Σ Φ
) dV / Σ Φ (
) dV , (2.10-11)
∫∑
g
x2,
g
∫∑
g ( x1,
g
g
g
where Σ x1,g and Σ x2,g are macroscopic cross-sections of the material specified by the user. The
reaction denoted by x1 and x2 are specified among Fission, Capture, Absorption and Production. The
option to change the numerator or denominator of Eq.(2.10-11) to be unity (1.0) is also prepared. The
range of volume integration can be adjusted by input. This volume integration option is applicable
only for the flux calculated by CITATION.
The cross-sections for the detectors have to be prepared before entering this routine
(macroscopic ones in MACRO or MACROWRK for (a), (b) and (d) reaction rate ratio, and
microscopic ones in MICREF for (c) spectrum index).
Following input data are required if IC18 > 0 in Sect.2.2.
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