So apparently the Bunker Busters are in limited quantities with IDF. They are likely to need replenishments. A couple of nuclear facilities are too fortified to be destroyed using the current munitions being used in Iran. The IAF is also abstaining from completely destroying some structures as they risk absolute contamination/leakage. A retired german ambassador to NATO provides his comments:
Seems to be talking about the MOP, GBU-57A/B.
It is only carried by the B-2, so it's natural the Israelis cannot do it.
14T of pure anger that can go through 60 m of earth.
Fordow is at least 80-90 m deep, with a combination of granite and 10000 psi concrete, so it's gonna need 3 of these puppies lobbed at it just to get through 1 point. The best Israeli weapon can only do up to 20-30 m.
In 2024, Beirut, the Israelis wanted to attack a Hezbollah stronghold 18 m underground to kill Hassan Nasrallah. They had to drop 85 BLU-109 and some GBU-28 to initiate penetration at effectively the same spot to get through, at multiple points of course, and to ensure overkill. You can see why the Israelis need American assistance to get through 90 m, through multiple points and multiple layers of the facility.
For example, just to hit 3 entrances, the Israelis would need 60 BLU-109s at 3 points each. And about 50 more to deal with the insides at 3-5 points via weak points like ventilation shafts. Even more for overkill. But to penetrate the mountain itself, the BLU-109 cannot do the job, making the exercise pointless.
With GBU-28, the numbers drop to 60 or so, but still not enough.
But with GBU-57 it's doable. A combination of penetration and seismic disturbances can destroy the facility. So about 10 bombs for penetration in 3 areas of the main facility and another 10 via ventilation shafts so there's passage for the shockwave that can collapse entrances and other tunnels. 20 bombs require 10 B-2s. A second wave of 5 more B-2s a few hours apart with 10 bombs can finish the job.