Hello everyone, I’m a relatively new user of OpenMC and monte carlo simulation softwares in general. I’ve tried some examples and then tried to do some simple pin simulations with certain height. The geometry i used is based on the NuScale fuel parameter. When i use the reflective boundary type i got this error warnings.
WARNING: After particle 443 crossed surface 592 it could not be located in any
cell and it did not leak.
ERROR: Maximum number of lost particles has been reached.
Based on that error, im assuming that the problem involves the finite height of the pin and the infinite height of the boundary. Here are the lines of geometry.
#Upper-Lower
b1_max = openmc.ZPlane(z0=100.076)
b1_min = openmc.ZPlane(z0=-100.076)
#Stack of 200.152 cm
#Fuel-Gap-Cladding-Moderator
r1 = openmc.ZCylinder(r=0.81153/2)
r2 = openmc.ZCylinder(r=0.82804/2)
r3 = openmc.ZCylinder(r=0.94996/2)
#Pitch
x1_max = openmc.XPlane(x0=0.62992)
x1_min = openmc.XPlane(x0=-0.62992)
y1_max = openmc.YPlane(y0=0.62992)
y1_min = openmc.YPlane(y0=-0.62992)
#Universe pin
pin_universe = openmc.Universe()
#Fuel Cell
fp_cell = openmc.Cell()
fp_cell.fill = fp
fp_cell.region = -r1 & +b1_min & -b1_max
pin_universe.add_cell(fp_cell)
#Gap
gap_cell = openmc.Cell()
gap_cell.fill = gap
gap_cell.region = +r1 & -r2 & +b1_min & -b1_max
pin_universe.add_cell(gap_cell)
#Cladding
clad_cell = openmc.Cell()
clad_cell.fill = clad
clad_cell.region = +r2 & -r3 & +b1_min & -b1_max
pin_universe.add_cell(clad_cell)
#Moderator
water_cell = openmc.Cell()
water_cell.fill = water
water_cell.region = +r3 & +b1_min & -b1_max & +y1_min & -y1_max & +x1_min & -x1_max
pin_universe.add_cell(water_cell)
outside = openmc.rectangular_prism(1.25984, 1.25984, boundary_type=“reflective”)
root_cell = openmc.Cell(fill=pin_universe, region=outside)
root_univ = openmc.Universe(cells=[root_cell])
geometry = openmc.Geometry(root_univ)
geometry.export_to_xml()
Is there any further explanation and clarification for this error? Thank you in advance for your help.