Would-be "SSN Countries" US Rejected: RL32418 Part 1.

Much military information, normally Secret throughout the West, Russia and China, is Unclassified in the US, via the US Government supported/manned Congressional Research Service (CRS).

See the CRS' February 13, 2024 report RL32418

titled “Navy Virginia-Class Submarine Program and AUKUS Submarine Proposal: Background and Issues for Congress”

at https://sgp.fas.org/crs/weapons/RL32418.pdf

For the record - Excerpts include:

[Page 16] "Previous Countries That Requested but Did Not Receive U.S. Naval Nuclear Propulsion Technology 

Overview

U.S. submarine technology and naval nuclear propulsion technology, reflecting decades of cumulative U.S. Navy research, development, design, construction, and operational experience, are generally considered crown jewels of U.S. military technology and consequently are highly protected. As noted earlier, the technical (including acoustic) superiority of U.S. Navy nuclear powered submarines is generally considered a foundation of U.S. superiority in undersea warfare, which in turn underpins a U.S. ability to leverage the world’s oceans as a medium of operations and maneuver, deny that to others, and thereby generate a huge asymmetric strategic advantage for the United States. 

Given both its high degree of importance to overall U.S. national security strategy and U.S. technical superiority in the field, U.S. naval nuclear propulsion technology to date has been shared with only one other country—the UK, through an arrangement begun in 1958 reflecting the U.S.-UK special relationship and U.S.-UK cooperation on nuclear-related matters dating back to the Manhattan project in World War II. 

[Page 17] As detailed below, during the Cold War, when the United States and its allies were engaged in an extended, high-stakes, and costly strategic competition against the Soviet Union and Warsaw Pact allies, the United States reportedly turned down requests from four U.S. treaty allies [other than the UK, namely]—France, Italy, the Netherlands, and Japan—to share U.S. naval nuclear propulsion technology. A fifth U.S. treaty ally—Canada—also requested but did not receive this technology. 

Canada canceled its SSN project before the United States acted fully on Canada’s request. A sixth country, Pakistan, also requested but did not receive the technology.

Detailed Discussion

In a November 18, 1987, presentation at a conference in Ottawa, Canada, U.S. Navy Captain Robert F. Hofford, the U.S. naval attaché in Ottawa—who stated that he was expressing his own views, which did not necessarily reflect those of the U.S. government—stated that 

Canada is not the only country that has requested this particular advantage from the U.S. As a matter of fact, Canada stands at the end of a line of about six different nations [other than the UK] that have requested exactly the same support from the U.S. for [a] nuclear submarine program. In fact we have turned them all down up to this point, so Canada is in a unique position of being the first country other than the British to be allowed or to even start a technology information flow that will allow the country to pursue its lines toward a nuclear program.39 

Regarding France, Italy, and the Netherlands, a November 5, 1987, letter from Representative Melvin Price to Secretary of Defense Caspar W. Weinberger and Secretary of Energy John S. Herrington, the full text of which is reprinted in Appendix E, states in part

It is important to appreciate that there is nothing new about an ally wanting our naval nuclear propulsion technology—or about the consistently strong U.S. policy against its releases. Over the years, we have turned down requests from a number of countries, including France, Italy, and the Netherlands.

 Regarding France, a 1989 journal article on assistance that the United States provided to France on the design of French nuclear warheads stated 

One area in which the French requested but did not receive help was in antisubmarine warfare (ASW) technology and, in particular, in silencing their own ballistic missile submarines to make them less easily tracked by Soviet hunter-killers. The U.S. Navy adamantly opposed any such assistance. Behind the navy’s position was the extreme sensitivity of its own counter-ASW regime. “The security of our Poseidon-Trident force was so important that we were not going to share with anybody else the methods we used to preserve it,” a senior civilian told me. Another said, “This is a jewel the navy will give to no one.”40 

Regarding Japan, Admiral Kinnaird R. McKee, then-Director of the U.S. Naval Nuclear Propulsion Program (aka Naval Reactors), testified in March 1988: 

Frankly, I think Japan is smart enough, if they really want to, to develop a phase-to-phase [sic: phased-array] radar.41 They have also asked us for help in nuclear submarines. We say[,] “If you want to get into the nuclear submarine business, go ahead and do it. You don’t need our help.”42

Regarding Pakistan, Admiral McKee testified in March 1988: “We have a letter from the Pakistanis who want one [i.e., a U.S. nuclear-powered submarine] because the Soviets gave [sic: leased] one [i.e., a Soviet nuclear-powered submarine] to India.43

Admiral McKee’s testimony about Japan and Pakistan was given in connection with a project that Canada initiated in 1987 to acquire a force of 10 to 12 UK- or French-made SSNs. A choice by Canada to select the UK SSN design (the Trafalgar-class design) would have involved the transfer to Canada of naval nuclear propulsion technology in the Trafalgar-class design that was derived from the naval nuclear propulsion technology that the United States provided to the UK beginning in 1958, which would have raised a question of U.S. approval for a potential sale of UK-made SSNs to Canada. The issue was discussed in a 1988 CRS report.44 Canada canceled its SSN project in 1989, mooting the potential question of whether to share with Canada naval nuclear propulsion technology in the Trafalgar-class design that was derived from the naval nuclear propulsion technology that the United States provided to the UK beginning in 1958. For 1987-1988 letters and statements from Members of Congress regarding the Canadian SSN project, see Appendix E.

[Footnotes]
39 Transcript of presentation.
40 Richard H. Ullman, “The Covert French Connection,” Foreign Policy, Summer 1989 (No. 75): 16-17, accessed at https://www.jstor.org/stable/1148862
41 Admiral McKee’s testimony at this point is referring to a proposal at the time, which he was asked to comment on, to sell to Japan the U.S. Navy’s surface ship Aegis weapon system, which included the SPY-1 phased-array radar. The system was eventually sold to Japan and is now used on eight Japanese destroyers. The system was also sold to South Korea, Australia, Spain, and Norway for use on ships in the navies of those countries. For more on the Aegis system, (continued...) Navy Virginia-Class Submarine Program and AUKUS Submarine Proposal Congressional Research Service 18 say[,] “If you want to get into the nuclear submarine business, go ahead and do it. You don’t need our help.”
42 Regarding Pakistan, Admiral McKee testified in March 1988: “We have a letter from the Pakistanis who want one [i.e., a U.S. nuclear-powered submarine] because the Soviets gave [sic: leased] one [i.e., a Soviet nuclear-powered submarine] to India.
43 Admiral McKee’s testimony about Japan and Pakistan was given in connection with a project that Canada initiated in 1987 to acquire a force of 10 to 12 UK- or French-made SSNs. A choice by Canada to select the UK SSN design (the Trafalgar-class design) would have involved the transfer to Canada of naval nuclear propulsion technology in the Trafalgar-class design that was derived from the naval nuclear propulsion technology that the United States provided to the UK beginning in 1958, which would have raised a question of U.S. approval for a potential sale of UK-made SSNs to Canada. The issue was discussed in a 1988 CRS report.
44 Canada canceled its SSN project in 1989, mooting the potential question of whether to share with Canada naval nuclear propulsion technology in the Trafalgar-class design that was derived from the naval nuclear propulsion technology that the United States provided to the UK beginning in 1958. For 1987-1988 letters and statements from Members of Congress regarding the Canadian SSN project, see Appendix E."