There are many prepositions that can be used with "working clearance" - 'for', 'on', 'without', etc. Often, a preposition isn't used. It's best you give us an example on how you want to use "working clearance" to get the right answer.

Use during with "working clearance "

'working clearance' is usually a very specific technical phrase. As Greg suggested, please give us the context, so that we can suggest the right preposition, but also check that you have the right phrase.