In this 2005 interview, former INR official Wayne White discussed an Iraqi Exocet strike on the Bushehr reactor:

There was a fear factor involved in firing the Exocet missile at a ship. In order to get a solid missile lock on the target, you released the missile about 30 miles away from the target using locking radar on the attacking aircraft itself. You had to wait, guiding the missile, as you remained in the area marking time (the military calls it loitering) until the sea skimming missile got within about five kilometers, which is darn close, to the intended maritime target. Then the missile’s own short-range radar got a final lock and sent a signal back to the aircraft that no further assistance was required. What the Iraqi pilots were doing, with Iranian aircraft frequently scrambling against them, would be to leave the area before the aircraft had fully guided the missile to the point at which the missile itself locked onto the target. In this situation, the missile would go wandering around a portion of the Gulf looking for a target, which often wasn’t the intended target.

… Iran’s first nuclear plant was practically right on the Gulf at Bushehr,not too far from Kharg Island. The Bushehr reactor had a high dome profile. The dome was being constructed before the machinery was being installed. One of the sea skimming missiles hit the nuclear reactor dome. Why? Missiles went for a high radar profile, which is why all the tankers were hit in the rear. A tanker is a long flat vesselwith a big superstructure in the rear, so the sea skimmer would go toward the rear. It was mainly designed to destroy warships, because of their smoke stacks, bridge, radars, etc., created the highest profile in the center of the vessel. But the tanker was not an ideal target for this missile. It always hit the rear.