# no chain specified, either manually or under depletion\_chain in environment variable OPENMC\_CROSS\_SECTIONS

**URL:** <https://openmc.discourse.group/t/no-chain-specified-either-manually-or-under-depletion-chain-in-environment-variable-openmc-cross-sections/567>\
**Category:** User Support\
**Created:** [March 11, 2020, 5:55am UTC](https://openmc.discourse.group/t/no-chain-specified-either-manually-or-under-depletion-chain-in-environment-variable-openmc-cross-sections/567 "2020-03-11T05:55:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Auliyah11](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Auliyah11](https://openmc.discourse.group/u/Auliyah11)\
**Post date:** [March 11, 2020, 5:55am UTC](https://openmc.discourse.group/t/no-chain-specified-either-manually-or-under-depletion-chain-in-environment-variable-openmc-cross-sections/567/1 "2020-03-11T05:55:16Z")

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Dear All,

Does anyone know what happened with this and what should i do?

Thx,  
Auliyah

 ![WhatsApp Image 2020-03-10 at 22.47.34.jpeg](https://global.discourse-cdn.com/free1/uploads/openmc/original/1X/61ff6d1a73c0585871ade3846a640672739d56e7.jpeg)

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**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\
**Post date:** [March 11, 2020, 9:26am UTC](https://openmc.discourse.group/t/no-chain-specified-either-manually-or-under-depletion-chain-in-environment-variable-openmc-cross-sections/567/2 "2020-03-11T09:26:38Z")

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You are not specifying depletion chain file for transmutation of nuclides. Add following line…

chain\_file = ‘./chain\_simple.xml’  
op = openmc.deplete.Operator(geometry, settings, chain\_file)

You can download depletion chain file from [https://press3.mcs.anl.gov/openmc/depletion-chains/](https://press3.mcs.anl.gov/openmc/depletion-chains/)

Best regards  
Pranto