# SFR (Sodium Fast Cooled Reactor)

**URL:** <https://openmc.discourse.group/t/sfr-sodium-fast-cooled-reactor/2438>\
**Category:** User Support\
**Created:** [November 4, 2022, 1:33pm UTC](https://openmc.discourse.group/t/sfr-sodium-fast-cooled-reactor/2438 "2022-11-04T13:33:20Z")\
**Posts on this page:** 1\
**Showing post:** 8

<div class="post-metadata">

**Author:** ![wahidluthfi](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/wahidluthfi/32/3375_2.png) [@wahidluthfi](https://openmc.discourse.group/u/wahidluthfi)\
**Post date:** [July 19, 2024, 2:21am UTC](https://openmc.discourse.group/t/sfr-sodium-fast-cooled-reactor/2438/8 "2024-07-19T02:21:31Z")

</div>

Dear users,  
If you think there were some geometry definition errors on your script, i.e. particle lost as you encounter, I recommend you to turn on the geometry debug mode

```auto
openmc.run(geometry_debug=True)

```

These are some discussions about troubleshooting these kinds of error

> [@Sodium Fast Reactor Core Code Help](https://openmc.discourse.group/t/sodium-fast-reactor-core-code-help/2894/3):
>
> @Michael_White I would take a look at the user’s guide section on lost particles: [https://docs.openmc.org/en/stable/usersguide/troubleshoot.html#error-maximum-number-of-lost-particles-has-been-reached](https://docs.openmc.org/en/stable/usersguide/troubleshoot.html#error-maximum-number-of-lost-particles-has-been-reached)

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_[View the full topic](https://openmc.discourse.group/t/sfr-sodium-fast-cooled-reactor/2438)._