# Lower K\_eff value then expected
**URL:** https://openmc.discourse.group/t/lower-k-eff-value-then-expected/4463
**Category:** User Support
**Created:** [June 26, 2024, 12:12pm UTC](https://openmc.discourse.group/t/lower-k-eff-value-then-expected/4463 "2024-06-26T12:12:44Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Aaron\_G](https://openmc.discourse.group/u/Aaron_G)
#### Post date: [June 26, 2024, 12:12pm UTC](https://openmc.discourse.group/t/lower-k-eff-value-then-expected/4463/1 "2024-06-26T12:12:44Z")
Hi, ive had this error for a while now and cant seem to fond the issue. My av K\_eff from another simulation for the same model was found to be in the region of 1.3 to 1.4 however im getting values of 0.011. So clearly something is wrong. Any help would be appreciated, im new to Openmc and currently have no idea why this is happening.
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### Author:  [@Aaron\_G](https://openmc.discourse.group/u/Aaron_G)
#### Post date: [June 26, 2024, 12:17pm UTC](https://openmc.discourse.group/t/lower-k-eff-value-then-expected/4463/2 "2024-06-26T12:17:10Z")
[http://localhost:8888/lab/tree/Reactor\_core/Finished\_Reactor\_%20(1).ipynb](http://localhost:8888/lab/tree/Reactor_core/Finished_Reactor_%20(1).ipynb)