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

triangular grid points .
Difference from IGT=14 is that 1) coolant regions are divided by
triangular meshes, 2) each pin rod can have the particular size, and 3).
trapezoidal shape regions near the outer boundary of the assembly can
simulate the wrapper tube and inter-assembly gap.
As the perfect reflective boundary condition is not supported, the
isotropically reflective condition is applied.
S-Regions are numbered by the rules: 1) coolant regions ahead of pin
rod regions. For coolant regions, 2.1) from inner to outer measured from
the central axis, 2.2) small Y-abscissa to large Y-abscissa, For pin rod
regions, 3.1) inner to outer in a pin rod, 3.2) small Y-abscissa to large
Y-abscissa, 3.3) inner to outer measured from the central axis.
= 16 Rectangular pillar divided by X-Y coordinates of quadrant symmetry
with pin rods on grid points.
This type permits the placement of pin rods on any grid point of an
x-y division of a rectangular lattice cell. Every pin rod has its own radius
with annular sub-division. This model differs from the model IGT=13 by
applying the perfect reflective boundary conditions always on the left
surface and on the lower surface.
When IBOUND=1 is specified as the outer boundary condition, the
perfect reflective condition is applied on the right and the upper surfaces.
S-Regions are numbered by the rules 1) coolant regions ahead of pin
rod regions, 2) small Y-abscissa to large abscissa, 3) small X-abscissa to
large abscissa, 4) inner to outer in a pin rod.
2 NZ Total number of Sub-Regions
3 NR Total number of T-Regions
4 NRR Total number of R-Regions
5 NXR Total number of X-Regions
6 IBOUND Outer boundary condition of the cell calculation
48