openmc.model.RectangularParallelepiped usage

User Support
1

Hi all !
I’m trying to insert a openmc.model.RectangularParallelepiped() in another openmc.model.RectangularParallelepiped() : method introduced with 0.12 version).

Following XML geometry code is produced by python code below.

<geometry>
  <cell id="1" material="1" name="Cell1" region="1 -2 3 -4 5 -6" universe="1" />
  <cell id="2" material="2" name="Cell2" region="7 -8 9 -10 11 -12 (-1 | 4 | -3 | 4 | -5 | 6)" universe="1" />
  <surface coeffs="-5.0" id="1" type="x-plane" />
  <surface coeffs="5.0" id="2" type="x-plane" />
  <surface coeffs="-5.0" id="3" type="y-plane" />
  <surface coeffs="5.0" id="4" type="y-plane" />
  <surface coeffs="-5.0" id="5" type="z-plane" />
  <surface coeffs="5.0" id="6" type="z-plane" />
  <surface coeffs="-10.0" id="7" type="x-plane" />
  <surface coeffs="10.0" id="8" type="x-plane" />
  <surface coeffs="-10.0" id="9" type="y-plane" />
  <surface coeffs="10.0" id="10" type="y-plane" />
  <surface coeffs="-10.0" id="11" type="z-plane" />
  <surface coeffs="10.0" id="12" type="z-plane" />
</geometry>

Produced by this python code :

import openmc

mat_meat = openmc.Material()
mat_meat.add_nuclide("U235", 1.0, "wo")
mat_meat.set_density("g/cm3", 1.0)

mat_al = openmc.Material()
mat_al.add_nuclide("Al27", 1.0, "ao")
mat_al.set_density("g/cm3", 2.7)

mats = openmc.Materials([mat_meat, mat_al])
mats.cross_sections = "/home/julien/Documents/codes/endfb80_hdf5/cross_sections.xml"
mats.export_to_xml()

dim=[10.,10., 10.]
dim2=[20.,20., 20.]

parrallelepiped_surf = openmc.model.RectangularParallelepiped(-dim[0]/2,dim[0]/2,-dim[1]/2,dim[1]/2,-dim[2]/2,dim[2]/2)
parrallelepiped_surf2 = openmc.model.RectangularParallelepiped(-dim2[0]/2,dim2[0]/2,-dim2[1]/2,dim2[1]/2,-dim2[2]/2,dim2[2]/2)

parrallelepiped_cell = openmc.Cell(name="Cell1" , fill=mat_meat, region = -parrallelepiped_surf)
parrallelepiped_cell2 = openmc.Cell(name="Cell2" , fill=mat_al, region = -parrallelepiped_surf2 & +parrallelepiped_surf)

p = openmc.Universe()
p.add_cells([parrallelepiped_cell, parrallelepiped_cell2])

geom = openmc.Geometry(p)
geom.export_to_xml()

plot_xy= openmc.Plot()
plot_xy.origin = (0, 0, 0)
plot_xy.width = (50.,50.)
plot_xy.pixels = (1000, 1000)
plot_xy.basis = 'xy'
plot_xy.id = 1
plot_xy.colors={mat_meat:"Red", mat_al:"Gray"}
plot_xy.color_by='material'

openmc.plot_inline(plots=[plot_xy])

I was expecting this definition for 2nd cell:
<cell id="2" material="2" name="Cell2" region="7 -8 9 -10 11 -12 (-1 | 2 | -3 | 4 | -5 | 6)" universe="1" />

Is there a misuse or a problem ?

Best regards,

Julien

2

Hi Julien! Thank you for reporting this.

This is indeed a bug and is specific to the use of the positive halfspace of the RectangularParallelepiped object. I’ll submit a fix for this ASAP.

3

@pshriwise’s fix has been merged in the develop branch, so this will be part of the next release.

4

Thx for your answers and for fixing it. For my information, when is planned the next release ?

Best

Julien

5

We should have another release out by the end of the year or sooner.