Jun's, on July 19, 2026's comments and links of July 19, 2026 spawned a wide variety of interesting topics and issues. South Korea (SK's) bid for US help not only relates to SSN construction (KSS-N) but an SK desire to build SSBNs (SK-SSBNs) to deter nuclear armed North Korea.
SK's program is also a trigger "justifying" Japan building its own Mutsu-class nuclear submarines. AUKUS (from good US, UK etc intelligence) can be seen as anticipating the above - justifying Australia's wants - AUKUS Pillar 1.
Australia is relying on UK and US assistance, at great cost. SK is relying on US assistance and international legal permission to use reactors for military/naval purposes. SK would also have liaised with France for 40+ years due to France's long experience with lower proliferation sensitivity-safer-cheaper LEU submarine reactors.
Of major value is Jun’s provision of an unofficial
translation of Seong-Chang CHEONG's, Vice President, Sejong Institute's
softpower@sejong.org Strategy and Roadmap for ROK-France Cooperation on
Nuclear-Powered Submarines: EU-Based Naval Integration and a Mutually
Beneficial Partnership Model at SEJONG FOCUS, February 10, 2026 at https://sejong.org/web/boad/1/egofiledn.php?conf_seq=22&bd_seq=12692&file_seq=41163
The Strategy and Roadmap is important for what it says and eventually says. Particularly on page 4:
"France is precisely the only Western nation to have accumulated more than 40 years of experience in all three of these areas [including LEU reactors] since the commissioning of its first Rubis-class attack submarine in 1983. France has designed, built, and operated a total of 17 nuclear-powered vessels: 6 Rubis-class SSNs, 6 Suffren-class SSNs (including those under construction), 4 Triomphant-class SSBNs, and the aircraft carrier Charles de Gaulle…”
The above statement is so far incorrect, as it omits the not usual 4 SSBNs but 6 French Redoutable-class SSBNs that each used up to 90% HEU reactors.
Only further down on page 4 of Strategy and Roadmap is France's use of HEU remembered:
"France
also has a history of using highly enriched uranium (HEU) in its early nuclear
submarine development. However, it has now fully transitioned to LEU. The early
variants of the Le Redoutable-class SSBNs, France’s first independently
developed strategic nuclear submarines in the 1970s, were equipped with
reactors using weapons-grade HEU. In the 1960s, while enrichment capabilities
were limited, highly enriched fuel was essential to increase the power output
of compact submarine reactors. Weapons-grade uranium produced at the
Pierrelatte military enrichment facility was used for this purpose."
Some Background and Issues on France's Wise Choice to Stick with LEU
Noting Submarine Matter's articles France’s Future SSBN “SNLE 3G” Starts Production of March 28, 2024; France's New K22 reactor for Carrier & 3G SSBN of December 27, 2023; and French LEU Reactor & SSN Implications of March 24, 2023:
The USN, and partly the UK RN, rely on the US' massive HEU naval reactor industrial
base to develop new submarine reactor technology and to create the 94+% HEU fuel.
If HEU submarine reactors and piping go drastically wrong - as with the UK's deeply flawed PWR2 reactors - HEU problems seem much harder and more expensive to rectify than regularly fixed LEU reactors.
Perhaps the engineering and potentially toxic health problems of accessing the PWR2's HEU assembly is the the problem that has "beached" all of the UK RN's Astute SSNs simultaneously and, I suspect, HMS Vanguard SSBN (withdrawn under inspection and maintenance for 10 years 2012 to 2022).
If the UK's future HEU PWR3 and/or PWR3+/PWR4 reactors fail to resolve the UK's PWR2 reactor technical disaster one hopes it doesn't impact Australia's SSN-AUKUS program. This is a hugely expensive issue people worry about in Canberra.
To avoid the English reactor disease should Australia plead with the US to sell us (at even greater expense) not 3, not 5, but all 8 SSNs Australia is seeking under AUKUS? Unlike the UK the US apparently makes reliable reactors.
I think the UK and US would prevent Australia turning to French LEU technology. One reason is the RAN officers/crew and shipyard workers currently receiving Top Secret nuclear training in the US and UK would not be trusted by the US and UK NOT to pass this Anglosphere SSN and reactor knowledge onto France.
Also how many countries can we throw Australian taxpayer's money at in our SSN quest? Not only to the US and UK, but to France and maybe even to South Korea's (world's most efficient) submarine building sector?