# Depletion results question

**URL:** <https://openmc.discourse.group/t/depletion-results-question/2535>\
**Category:** User Support\
**Created:** [December 6, 2022, 3:12pm UTC](https://openmc.discourse.group/t/depletion-results-question/2535 "2022-12-06T15:12:33Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![fnovais](https://avatars.discourse-cdn.com/v4/letter/f/ec9cab/32.png) [@fnovais](https://openmc.discourse.group/u/fnovais)\
**Post date:** [December 6, 2022, 3:12pm UTC](https://openmc.discourse.group/t/depletion-results-question/2535/1 "2022-12-06T15:12:33Z")

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Hello. Quick question. I have a depletion calculation with results as:

```auto
[<StepResult: t=0.0, dt=86783400.0, source=1.834368e+20>,
 <StepResult: t=86783400.0, dt=86400.0, source=0.0>,
 <StepResult: t=86869800.0, dt=604800.0, source=0.0>,
 <StepResult: t=87474600.0, dt=0.0, source=0.0>]

```

My question is, for example, the `openmc_simulation_n0.h5` result is for t=0 or t=86783400 (after the first time step)?

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<div class="post-metadata">

**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\
**Post date:** [December 7, 2022, 5:13am UTC](https://openmc.discourse.group/t/depletion-results-question/2535/2 "2022-12-07T05:13:26Z")

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The first result (`openmc_simulation_n0.h5`) will correspond to the very first time point, t=0.

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<div class="post-metadata">

**Author:** ![fnovais](https://avatars.discourse-cdn.com/v4/letter/f/ec9cab/32.png) [@fnovais](https://openmc.discourse.group/u/fnovais)\
**Post date:** [December 7, 2022, 9:45pm UTC](https://openmc.discourse.group/t/depletion-results-question/2535/3 "2022-12-07T21:45:32Z")

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I ask because, with the setup below, I am only getting the first result (n0) with a non zero tally. Because of the zero source rate, I was expecting to get n0 and n1 tallies results and n2 and n3 empty. Am I missing something? If I set the second source rate to`(1*24*60*60, 1),`, the tally associated with `openmc_simulation_n1.h5` will not be empty.

```auto
timesteps_and_source_rates = [
    (365.25*24*60*60, 1.834368e20),
    (1*24*60*60, 0),
    (7*24*60*60, 0)
]

```

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<div class="post-metadata">

**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\
**Post date:** [December 7, 2022, 11:34pm UTC](https://openmc.discourse.group/t/depletion-results-question/2535/4 "2022-12-07T23:34:52Z")

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If you have three timesteps, you will get four results, one corresponding to the beginning of each timestep and one corresponding to the end of the last timestep. So, it is expected that the second and third set of results have zero reaction rates because the source rate you specified for those steps is zero. The result for the end of the final timestep uses the source rate from the last step, so it also inherits the zero source rate and hence has zero reaction rates as well.

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<div class="post-metadata">

**Author:** ![fnovais](https://avatars.discourse-cdn.com/v4/letter/f/ec9cab/32.png) [@fnovais](https://openmc.discourse.group/u/fnovais)\
**Post date:** [December 8, 2022, 1:07pm UTC](https://openmc.discourse.group/t/depletion-results-question/2535/5 "2022-12-08T13:07:30Z")

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Thank you very much!