# Segmentation fault, depletion source R2S calc

**URL:** <https://openmc.discourse.group/t/segmentation-fault-depletion-source-r2s-calc/6195>\
**Category:** User Support\
**Created:** [January 26, 2026, 9:36pm UTC](https://openmc.discourse.group/t/segmentation-fault-depletion-source-r2s-calc/6195 "2026-01-26T21:36:36Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ajbergeon](https://avatars.discourse-cdn.com/v4/letter/a/858c86/32.png) [@ajbergeon](https://openmc.discourse.group/u/ajbergeon)\
**Post date:** [January 26, 2026, 9:36pm UTC](https://openmc.discourse.group/t/segmentation-fault-depletion-source-r2s-calc/6195/1 "2026-01-26T21:36:36Z")

</div>

Hello Forums,

I’m trying to run a fixed-source calculation with the fixed source defined based on a depleted materials file. My method is similar to the rigorous 2-step method described in the documentation: [11. Decay Sources — OpenMC Documentation](https://docs.openmc.org/en/stable/usersguide/decay_sources.html)

I’m getting all the way to Step 6 with no issues but get a segmentation fault as soon as transport calculations start. Has anyone seen this before?

I’m running v0.13.3, and should note that the source definition is very complex (~400 source objects), as each fuel assembly material is defined individually to capture variations in material depletion due to variations in flux.