Create externe source in fixed source

Can we creates the external source in the case of fixed sources? If it is possible how ?

Yes, “fixed source” and “external source” can be considered synonymous. For details on how to specify the external source, see the documentation on the element which is specified in settings.xml:
http://mit-crpg.github.io/openmc/usersguide/input.html#source-element

If you have specific questions, feel free to send another message here.

Best regards,
Paul

thak you for your answers

I would like a file source binary path is given by the value of this element.