# The result of the k calculation using OpenMOC diverged

**URL:** <https://openmc.discourse.group/t/the-result-of-the-k-calculation-using-openmoc-diverged/4356>\
**Category:** User Support\
**Created:** [June 6, 2024, 1:38pm UTC](https://openmc.discourse.group/t/the-result-of-the-k-calculation-using-openmoc-diverged/4356 "2024-06-06T13:38:23Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Lishuaishuai](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/lishuaishuai/32/4219_2.png) [@Lishuaishuai](https://openmc.discourse.group/u/Lishuaishuai)\
**Post date:** [June 6, 2024, 1:38pm UTC](https://openmc.discourse.group/t/the-result-of-the-k-calculation-using-openmoc-diverged/4356/1 "2024-06-06T13:38:23Z")

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Hello everyone, since I can’t access the OpenMOC forum, I have to seek help here. When I use OpenMOC to verify the cross sections generated from OpenMC, I replaced rod elements with plate elements, and I noticed that the k calculation keeps diverging. However, if I set the energy groups to a very small number like casmo-70, k converges. Is this due to the specific nature of plate elements? Can anyone help me with this?Here is my input,Thank you!  
[mgxs-part-ii.ipynb](https://openmc.discourse.group/uploads/short-url/i133ml4v5fTkehg5SPQfFsV5DH8.ipynb) (285.6 KB)

 ![1717681019645](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/e/e4d069c074c4c9ae9aaa3c1eba4116e295b60dc8.png)