Naval nuclear propulsion depends on fuel policy

If nuclear submarines proliferate after AUKUS, are British or French reactor arrangements more likely to spread?

The British approach is more likely, but lifetime fuel avoids refuelling only if high-enriched-uranium production and stocks can support it.

Lower-enriched fuel requires a refuelling system, while higher-enriched fuel can last the vessel's service life. A lifetime core makes the British approach easier to export to a navy that does not want to build repeated refuelling infrastructure. Japan probably has the technical base to develop its own system and, at the time of the stream, did not appear to be pursuing nuclear submarines. The British approach does not remove the industrial constraint, because expanded submarine programmes would consume limited stocks of highly enriched uranium. Any proliferation scenario must consider fuel production and stockpiles alongside reactor design and hull construction.