%XSEC Card

This card is used to describe the cross section data. This card is conditional : either %XSEC or %XTAB card must be present

%XSEC	Variable	Description	Remarks
LINE 1	NG	Number of groups
	NMAT	Number materials
LINE 2	SIGTR(g)	Transport macroscopic XS for group g	Repeat LINE 2 NG times. And again repeat this input segment NMAT times.(See example below)
SIGA(g)	Absorption macroscopic XS for group g
NUF(g)	Nu * Fission macroscopic XS for group g
SIGF(g)	Fission macroscopic XS for group g
CHI(g)	Fission neutron spectrum for group g
SIGS(g,1:NG)	Scattering macroscopic XS from group g to other groups

Example:

%XSEC
2  5    ! Number of groups and number of materials
! sigtr   siga   nu*sigf sigf   chi   sigs_g1  sigs_g2
0.222222  0.010  0.000  0.000    1.0   0.1922   0.020
0.833333  0.080  0.135  0.135    0.0   0.000    0.7533   ! MAT1 : Outer Fuel
0.222222  0.010  0.000  0.000    1.0   0.1922   0.020
0.833333  0.085  0.135  0.135    0.0   0.000    0.7483   ! MAT2 : Inner Fuel
0.222222  0.0100 0.000  0.000    1.0   0.1922   0.020
0.833333  0.1300 0.135  0.135    0.0   0.000    0.7033   ! MAT3 : Inner Fuel + Control Rod
0.166667  0.000  0.000  0.000    0.0   0.1267   0.040
1.111111  0.010  0.000  0.000    0.0   0.000    1.1011   ! MAT4 : Reflector
0.166667  0.000  0.000  0.000    0.0   0.000    0.040
1.111111  0.055  0.000  0.000    0.0   0.000    0.000    ! MAT5 : Reflector + Control Rod