Custom S Alpha Beta Libraries

User Support
1

Hi all. I’m trying use an Sab set I have for 20% porous graphite. It was originally ace formatted, but I made some tweaks to this conversion script ( data/convert_lib80x.py at bcc99743f5c0efa0d7f3821201e04a31f8fd1d0d · openmc-dev/data · GitHub ) to convert it to the proper format and add it to my cross_sections.xml file. When I try to add the data to a material using the call material_name.add_s_alpha_beta(“c_graphite_20p”), OpenMC doesn’t recognize the name of this dataset and instead assigns the c_Graphite_30p data. Is there a way to force OpenMC to add my Sab library without manually adding the new Sab library into the _THERMAL_NAMES dictionary within the openmc/data/thermal.py file? Thanks!
-Josh

2

Hi Josh - thanks for sending your cross_sections.xml file separately. From that file, it looks like you’ve named the S(a,b) data set as “c_Graphite_20p”, but are using “c_graphite_20p” in your script? Here’s what I see in your cross_sections.xml:

 <library materials="c_Graphite_20p" path="home/josh/openmc_cross_sections/c_Graphite_20p.h5" type="thermal" />

Would you please try using the case-sensitive file name?

3

April, I checked the cases across my files and they seem to be consistent across the files. I’m realizing now that I mistyped in the forum post above. In my materials files I am actually using the call material_name.add_s_alpha_beta(“c_Graphite_20p”). Sorry for the confusion!

4

As suggested by April offline, in the same file as the material definition with the custom Sab library, adding the following code will prevent renaming the associated library:

import openmc.data.thermal as d
d._THERMAL_NAMES["c_Graphite_20p"] = "c_Graphite_20p"

Thanks April!

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