In what maybe an interesting information regarding the Korean nuclear submarine project, some submarine specs were displayed by KRISO (Korea Research of Ships and Ocean Engineering) (their leading state-led marine engineering organisation).
At the "2025 Defence Core Technology Planning and Performance Conference", they displayed a submarine model titled "KRISO SPL Submarine and Pumpjet" with the following specs:
L x B x D - 111.2 x 9.8 x 10.7 m
Displacement - 8,280 tons
Max. Speed - 30 kts
Source -
'24 국방핵심기술 기획·성과 컨퍼런스 - 3
Not sure if these are the exact specifications that the Korean nuclear submarines will have, but they seem oddly specific, and these numbers (8,000+ tons disp. and 30 kts speed) can only mean a nuclear submarine.
But if these turn out to be the actual specs, the Koreans might be designing an absolute monster considering this is their first attempt at actually building a nuclear submarine. Its bigger than the Astute and the Block IV Virginia.
Additionally, the project will be managed by a joint task force, comprising of 10 ministries/agencies (incl. the ministry of national defence, ADD, DAPA, ministry of trade, industry, and energy, ministry of economy and finance etc.) which will be overseen directly by the prime minister, and report to the president.
In a National Assembly hearing, the defence minister, Ahn Gyu-baek, also revealed that the detailed blueprint, including requirements, construction plans, and roadmaps will be presented within the next year (i.e., 2026).
This follows previous statements to the National Assembly by the defence minister and the national security advisor mentioning that the plan would be to start building the submarines in the later part of this decade (2027/28), for induction into service by 2035/36, with each submarine costing over KRW 3 trillion (USD 2.3 billion) with a total project expenditure of over KRW 20 trillion.
As I had speculated in this post, the Korean nuclear submarine will indeed be a monster, for what is essentially Korea's first attempt at nuclear naval propulsion. The class has been revealed to be "8000-ton class." One thing to note: Korean naval displacements are quoted for light displacement or surfaced displacement (for example - the 3,000-ton class KSS-III Batch - I displaces closer to 3300 tons surfaced and 3800 tons submerged). This one, the KSS-N, will displace somewhere between 8,000-9,000 tons surfaced. This range matches with the KRISO figure of 8,280 tons. Not sure about the submerged displacement; since this is expected to carry newer, longer ranged SLBMs. It will use LEU fuel.
Sources are linked below -
美 버지니아급 규모로 '대형' 분류…'해군력 강화' 북한에 맞대응 韓, 대형 잠수함 건조·국산 원자로 설계 역량 충분…6월 중순 한미 협의 개시 한국형 핵추진잠수함(핵잠) 건조 프로젝트 '장보고 N사업'이 베일을 벗으면서 구체적 제원에 대한 관심도 커지고 있다.정부는 지난해까지만 해도
www.news1.kr
정부는 지난해까지만 해도 5000톤급 배수량의 핵잠 건조를 고려했으나, 북한이 한국의 핵잠을 의식해 잠수함발사탄도미사일(SLBM) 탑재가 가능한 8000톤급 이상의 전략핵잠수함(SSBN) 건조를 추진하고, 5000톤급의 신형 구축함 건조에 속도를 내며 '동해 함대' 구축에 속도를 내는 점 등을 감안해 한국형 핵잠의 크기를 키운 것으로 분석된다.
South Korea issued a RFP for a new VLS for submarines capable of delivering a SLBM with an ejection weight of at least 10 tons.
www.navalnews.com
In addition to this, as had been said earlier, the submarines will be built entirely in Korea, to Korean submarine and reactor designs, and in Korean yards. This was again affirmed in the unveiling of the "KSS-N Nuclear-Type Submarine Aquisition Basic Plan" that was unveiled by their Defence Minister and the President on 26th May, 2026. The first submarine will be in water by 2035 (mid-2030s).
(서울=연합뉴스) 김효정 김철선 기자 = 정부가 2030년대 중반까지 첫 핵추진잠수함(핵잠)을 진수하고 2030년대 후반에는 해군에 배치한다는 ...
www.yna.co.kr
Exact quotes:
아울러 "대한민국 내에서 핵추진잠수함을 개발·건조하겠다"며 "우리 원자로와 조선 기술을 활용해 자주적으로 건조하겠다"고 밝혔다.
This again coincides with their SLBM development plan (first test from submerged platform - 2027, service by 2030-31, mass production by 2032-34). Whether its based on the Hyunmoo-5, which weighs 36 tons, or maybe a lighter and longer ranged missile remains to be seen. It is entirely possible that it could be a variant of the Hyunmoo-6 or the Hyunmoo-7, both of which have been confirmed to be in development by their Defence Minister in an interview.
The rumored investment is expected to be KRW 30 trillion, for at least 6 (previously cited), possibly 8-9 submarines (from a 2017 seminar by the Korean Navy to the National Assembly).
This shows a few things -
1. As said earlier, the Koreans were always designing for an eventual nuclear submarine, before last year's announcement merely formalised everything.
2. These submarines will be fully Korean, based on the "next-generation submarine" model unveiled by Hanwha Ocean in 2025 MADEX.
3. And most importantly, these represent a Korea gearing up for a nuclear deterrence by the 2040s. This will happen. 100%.
In case anyone might be interested in some additional context:
1. This is in context of the Korean government trying to get the program to a stage by 2030 (when the current President Lee's term ends) that even in the off chance the PPP (their conservative party) manages to win the Prez election, they wouldn't be able to reverse their armaments program (which is something all post-dictatorship conservatives have done).
2. This is in combination with trying to get full wartime OPCON by 2029. There's even rumors that SK wants the combined command dissolved. Their current president has long held a belief (which he has said publicly) that American bases in SK is akin to occupation or vassalage, and if the liberals win the 2030 prez elections, be sure that the US bases will be severely downsized, regulated, and essentially closed eventually.
3. All this is broadly alongside their efforts to become completely self-sufficient when it comes to military tech. They have already achieved that for the army (small arms, all forms armoured vehicles, tanks, artillery (both howitzers and rockets), and now increasingly, drones). They will achieve the same for the Navy by 2036. The ROKAF and their space force will take some time, before their indigenous programmes start yielding results.
