The user need to do the following steps in order to provide own site-specific value instead of default one:
Open database window by selecting Database from the main menu.
Expand tree in the Database window, find the corresponding table and double-click on its icon to open the table.
Make a copy of similar row (for example having the same nuclide) in the database table by selecting row in the table and clicking on the Make copy of selected rows button located on the toolbar. The copy of row will be placed at the bottom the table. It will contain user in the Data sorce column.
Modify the value in the new row to the site-specific one.
Click on the checkbox located in the Default column of new row. This will tell SAFRAN to use value from this row in safety assessment instead of default one.