Well, Israel is pretty confident that an Osirak type raid involves too much risk.
The Israeli Navy has oufitted some sub launched missiles that are nuclear capable. For some reason Dolphin class German subs come to mind.
These hi-speed underwater missiles are a direct response to them and the US Naval presence in the Gulf.
Again- they view these as defensive weapons.
I know you all do not agree, but the logic that they use is different.\
Why are Israeli subs in the PERSIAN gulf?
Hence, from the perspective of Iran, its very defensive.