How to specify the boron concentration (ppm) in calculation

User Support
1

Hi all,

I try to calculate the pin cell multi-group cross-section under different boron concentrations, but I don’t know how to set the boron concentration in ppm. Should it be specified in the moderator by using “material.add_nuclide” or “material.nuclide_element”? For different boron concentrations, does the density of water need to be recalculated manually using H, O and B?

Below is what I did:

boron_ppm=500

#borated water
water = openmc.Material(name=‘Borated Water’)
water.add_nuclide(‘H1’, 2)
water.add_nuclide(‘O16’, 1) #is it right? or how can I calculate the ‘atomic percentage’ from the atomic density？
water.add_element(‘B’,boron_ppm*1e6,‘wo’)
water.set_density(‘g/cm3’, 0.740582)

I found a python API " openmc.model.borated_water" that can specify the boron concentration in ppm, but no examples of using it were found.

Sincerely yours,
Yahui Wang

2

Using openmc.model.borated_water() is probably the way to go. Here is an example:

water = openmc.model.borated_water(boron_ppm=432.473,temperature=566,pressure=15)

Using the temperature and pressure you give, it automatically calculates the density. If you specify the density, it overrides the temperature and pressure.

3

Hi mkreher，

Thank you for your kind reply. I have another problem. Does ‘openmc.model.borated_water’ include S(α,β) table? Thank you again.

Sincerely yours,
Yahui Wang

4

Yes, it does! I see it in the source code.