So one is trying to model a 17x17 lattice with a 366 cm active fuel zone. There are 157 assemblies in the core.
2 is in the lattice map is water. The guide tube and water between assemblies would have different geometries and size.
The densities in the cell cards seem correct, and the radial and axial dimensions in the fuel rods and the cell pitch of ~12.6 cm seem correct. Above the active fuel zone would be the plenum (filled with He and stainless steel spring ~ 0.09 - 0.15 of the void volume with a height of about 20 cm). There are upper and lower endplugs (Zr-4 or ZIRLO) and stainless steel nozzle below and above the core.
It looks like you might have some gad in there. BTW - 5% is a bit high for a fresh core, without extensive holddown.