# Questions about depletion on fixed source simulation

**URL:** <https://openmc.discourse.group/t/questions-about-depletion-on-fixed-source-simulation/2861>\
**Category:** User Support\
**Created:** [March 27, 2023, 2:16am UTC](https://openmc.discourse.group/t/questions-about-depletion-on-fixed-source-simulation/2861 "2023-03-27T02:16:57Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Tianxiang](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/tianxiang/32/3806_2.png) [@Tianxiang](https://openmc.discourse.group/u/Tianxiang)\
**Post date:** [March 27, 2023, 2:16am UTC](https://openmc.discourse.group/t/questions-about-depletion-on-fixed-source-simulation/2861/1 "2023-03-27T02:16:57Z")

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Dear exports,  
I have a question about the depletion on fixed source simulation.I want to do transmutation calculations on a cube, and I know we can’t specify a specific energy spectrum, so I’m going to use openmc.stats.Discrete to accept 315 single energy groups and the corresponding intensities, but the results seem to be a bit problematic. Here is a simple screenshot of the code, where does the problem occur please.  
Tthank you very much for your help.

 ![1679883328566](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/a/aeedef82c956f089f2e3e8a67a75dd40f044f9db.png)  
 ![1679883393589](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/5/5bd13886967b842a70c3e5e487dc2434a1856bd8.png)