Assuming that Israeli Intelligence will come to the IAEA with information on a secret site where Iran continues to enrich uranium or to secretly build another installation, it will take the powers 24 days to arrive at the place, by which time the Iranians will have had enough time to clear away all incriminating evidence.
I am Breaking Bad’s Gustavo Fring. I run a huge meth amphetamine lab in the basement of a laundry. The Albuquerque DEA has to give me 24 days’ notice before they are allowed to inspect the premises. I don’t usually swear, but Los Pollos Hermanos! Watch those chickens fly. (NB: only fans of Breaking Bad, the greatest ever American TV drama, will understand this punchline. Others must Google it).