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library, because of their smaller contributions to neutron energy transfer in practical reactor calculation.
In the SRAC calculation, the temperature interpolation is done not only for the resonance shielding
factors, but also for the thermal scattering matrices. The interpolation of thermal scattering matrices is
made by using the Lagrandian three point interpolation formula 18) ,
σ ( T ) = ( T − T
2
)( T − T
+ ( T − T )( T − T
1
+ ( T − T )( T − T
1
3
) σ ( T ) / ( T − T
3
2
1
) σ ( T
2
) σ ( T
3
1
) / ( T
2
) / ( T
3
2
)( T
− T )( T
1
− T )( T
1
1
2
3
− T
3
− T
− T
)
3
2
)
)
(1.3-1)
where, T is the specified material temperature, T 2 is the nearest temperature to T in the tabulated
temperature, T 1 and T 2 are the neighboring temperatures of T 2 in the tabulated temperatures.
Extrapolation is not available. The scattering matrices are omitted for most of FP (Fission Product)
nuclides (cf. Sect.8.2).
1.4 Data Storage in PDS (Partitioned Data Set) Files
In the SRAC system, the integrated codes exchange the information such as cross-sections and
fluxes which are stored in the common format file called as PDS file as shown in Fig.1.2-1. PDS file
was, originally, the partitioned data set (of only one storied hierarchy) in binary format which is
peculiar in the old IBM/FACOM machines with the ‘MSP’ operating system. Formerly it was an
obstacle to export the SRAC system to other machines. As a hierarchical file structure is standard
nowadays, the SRAC system is exportable.
Public Libraries
PTHERMAL
UTHERMAL
UMCROSS
UFAST
PFAST
PMCROSS
read
CU050000 (control data for U-235 members)
FU050000 (self shielding factors)
MU050000 (principal cross sections data)
YU050000 (delayed neutron data)
CPU90000
}
FPU90000
(members for Pu-239)
MPU90000
YU050000
:
SRAC
code
read
write
search
rename
delete
FLUX
MICREF
MACROWRK
MACRO
CEL1A010
CEL2A010
:
:
Fig.1.4-1
File I/O with Partitioned Data Set (PDS) files
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