How to move SSISDB database
It is more or less the same as moving the data files for a user database, but
you can follow the steps in the documentation To Move the SSIS Database as it has some additional good precautions noted:

Follow the instructions for moving user databases. For more information, see Move User Databases.
Ensure that you back up the master key for the SSISDB database and protect the backup file. For more information, see To Back up the SSIS Database.