This doesn’t pass the smell test.
1. The events are 30 - 50 km down.
2. The location is so close the the Persian Gulf that US aircraft could conduct surveillance without violating Iranian airspace. Sniffer aircraft could easily pick up traces of the tests.
How many places would there be in Iran where they could do something like this?
‘Sniffer aircraft could easily pick up traces of the tests.’
I don’t imagine they would acknowledge picking up any traces if it really was a nuke test...that would be tightly held info. Maybe this is what Biden and Powell have been referencing in their words about pending crisis for the newly elected President. Powell even gave a date range. Neither of them should have opened their mouths on this.