A few weeks ago when the US/Australian sub deal was announced it was notable(outside of the diplomatic snafu) because it was only the second country the US has

A few weeks ago when the US/Australian sub deal was announced it was notable(outside of the diplomatic snafu) because it was only the second country the US has ever shared its propulsion technology with[1]. The only other country at that point was the UK. Also see Q3 here: "Why is the technology so closely guarded?"[2]. Basically putting nuclear reactors on submarines and having those submarines remain silent is very hard to do. [1] https://www.washingtonpost.com/politics/2021/09/15/us-will-share-nuclear-submarine-technology-with-australia-part-new-alliance-direct-challenge-china/ https://www.washingtonpost.com/politics/2021/09/15/us-will-s... [2] https://defense360.csis.org/what-is-the-importance-of-the-aukus-announcement-on-submarines/ https://defense360.csis.org/what-is-the-importance-of-the-au...