I am a beginner at OpenMC. I currently want to randomly disperse Triso particles within a hollow cylindrical structure using the openmc.model.pack_spheres command, but I encountered an error. The error message indicates that openmc.model.pack_spheres does not support generation inside a hollow cylinder. Therefore, what method should I use to randomly disperse Triso particles within a hollow cylinder?
r_inner = openmc.ZCylinder(r=0.5)
r_fule = openmc.ZCylinder(r=1.3)
r_sleeve = openmc.ZCylinder(r=1.7)
r_hole = openmc.ZCylinder(r=2.05)
fuel_maxz = openmc.ZPlane(z0=27.3)
fuel_minz = openmc.ZPlane(z0=-27.3)
maxz = openmc.ZPlane(z0=29, boundary_type=‘reflective’)
minz = openmc.ZPlane(z0=-29, boundary_type=‘reflective’)
fuelrod_region = -r_fule & +r_inner & -fuel_maxz & +fuel_minz
spheres = openmc.model.pack_spheres(radius=0.046, region=fuelrod_region, pf=0.3)
trisos = [openmc.model.TRISO(0.046, triso_universe, center) for center in spheres]
