The Raptor being sold overseas was prohibited specifically by the Obey Amendment, there’s no specific US instrument to prohibit the sale of the Virginia class as far as I’m aware.
Read the second link in my post #517 above - it would require the repeal/amendment of several treaties and laws….
”…..While more specifics of the deal will be hammered out over the next 18 months, Congress can — and should — be skeptical of any “exception” that could weaken nonproliferation policy or insist on changes to avoid proliferation concerns.
Because the United States and Australia have an
agreement that does not allow this sort of military transfer, Congress will get a say in whether it is amended.
Section 123 of the U.S. Atomic Energy Act (AEA) of 1954 governs nuclear cooperation between the United States and other countries, laying out nine non-proliferation criteria. As recently as 2010, Congress permitted the Australian “123 agreement” to come into force until at least 2040. That deal, however, pertains only to civilian projects and explicitly forbids the transfer of materials for “military nuclear propulsion.”
The agreement also bans the transfer of fuel defined as “highly-enriched uranium” (HEU), meaning uranium enriched to 20 percent or higher in the isotope Uranium-235 (U-235). All United States nuclear submarines rely on fuel enriched to 93.5 percent in the isotope U-235, which technically qualifies as weapon-grade. A new arrangement with Australia, as well as the overall Foreign Military Sales agreement, will require separate Congressional approval processes that Congress will need to consider carefully……”