# Does OpenMC support transient simulation?

**URL:** <https://openmc.discourse.group/t/does-openmc-support-transient-simulation/3327>\
**Category:** User Support\
**Created:** [August 16, 2023, 12:40pm UTC](https://openmc.discourse.group/t/does-openmc-support-transient-simulation/3327 "2023-08-16T12:40:21Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lugaoqi](https://avatars.discourse-cdn.com/v4/letter/l/8baadc/32.png) [@lugaoqi](https://openmc.discourse.group/u/lugaoqi)\
**Post date:** [August 16, 2023, 12:40pm UTC](https://openmc.discourse.group/t/does-openmc-support-transient-simulation/3327/1 "2023-08-16T12:40:21Z")

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I want to try to do Monte Carlo transient simulations using OpenMC. Theoretically, I can do transient simulations by simply time-tagging each neutron, and I would like to know if OpenMC currently supports it?

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**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:** [August 19, 2023, 4:11am UTC](https://openmc.discourse.group/t/does-openmc-support-transient-simulation/3327/2 "2023-08-19T04:11:49Z")

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OpenMC will keep track of the time of particles and allows you to filter scores by time using the `TimeFilter` class. However, do note that if you have fissionable materials, delayed neutrons are not emitted at the correct time, so it is not possible to do transient simulations for fission reactors.