Instead of trying to put a bomb into the centre of the tunnel complex, where the centrifuges etc are.
Surely it would be easier to destroy the area just on inner side of the entrance doors?
The overpressure inside would render anyone inside useless or dead and the collapse would seal the tunnel (s) for a very long time.
Entombing the scientists as well.
The Iranians won't be able to get any heavy equipment into the area as the Israelis have air dominance and they could take out electrical infrastructure etc making the whole area a slow creeping morgue.