In this fortnightly online column, ADM journalist Corey Lee Bell covers defence news across Japan and the Republic of Korea.
Seoul looking to fast track a “Korean version of AUKUS”
South Korea could develop a small nuclear powered attack submarine (SSN) fleet within ten years, and deploy them “after the mid-2030’s,” South Korean defence officials told a parliamentary audit committee in Seoul on October 30.
The statements to the Defence Committee came only a day after the US President announced that Washington was willing to transfer nuclear technology and allow South Korea to build nuclear-powered submarines in the United States – an arrangement that has been called a “Korean version of AUKUS.”
Speaking to the Defence Committee in South Korea’s National Assembly, Seok Jong-geon, Commissioner of the Defense Acquisition Program Administration (DAPA), said that while it typically takes 10 years to build an SSN capability, the timeframe “could be somewhat shortened” through cooperation with the United States.
Ahn Gyu-back, South Korea’s Minister for National Defence, added that South Korea “already possesses the requisites to build nuclear submarines” – which include existing nuclear and shipbuilding industries, nuclear engineering institutions, and naval personnel trained to use submarine launched ballistic missiles (SLBM) systems.
He said he was confident that the project would not encounter major difficulties, asserting the nation has a proven capacity to build 3,000-plus tonne submarines. Ahn further stated that the use of non-military grade nuclear materials would soften international resistance, with Chief of Naval Operations Kang Dong-gil emphasising that the submarines will be powered by low-enriched (non-weapons grade) uranium.
Nuclear non-proliferation and the 123 Agreement
While South Korea has sporadically pursued an SSN capability for decades, efforts have intensified since the inauguration of its incumbent left-leaning president Lee Jae Myung in June.
One of the key obstacles the new administration has sought to address is the US-ROK Peaceful Nuclear Cooperation Agreement (or 123 Agreement), which bars Seoul from reprocessing spend nuclear fuel, enriching uranium above 20 per cent, and using nuclear materials for military purposes including nuclear propulsion.
The Republic of Korea’s (ROK) incumbent Minister of Foreign Affairs Cho Hyun, who promoted developing SSNs in his inauguration speech in July, has campaigned to amend the 123 Agreement- which has been opposed by non-proliferation advocates in the US Department of Energy and the State Department.
However, using low-enriched uranium in place of the highly enriched uranium typically employed in nuclear propulsion, would both reduce the scope of any amendment, and weaken long held US concerns of Seoul achieving nuclear latency (i.e. the capacity to rapidly weaponise nuclear materials).
Another potential suggestion for tackling the nuclear hurdle was President Lee’s proposal to strengthen energy security cooperation with Washington, including “make real progress in enriching uranium and reprocessing spent nuclear fuel” – a strategy consistent with Cho’s recommendation to convince Washington that enrichment and reprocessing would primarily serve industrial, as opposed to military, goals.
Despite the current proposal to use low enriched uranium for submarine propulsion, several South Korean experts, including the Sejong Institute’s Shin Beomcheol and the Korea Advanced Institute of Science and Technology’s (KAIST) YongHoon Jeong, have argued that highly enriched uranium remains the most feasible option.
Design and construction bottlenecks
Aside from concerns relating to nuclear proliferation, further obstacles lay in design and construction.
A design for Korea’s SSN is still yet to have been identified by Korean officials, although the use of a domestic design for a vessel “over 5,000 tonnes” was intimated by defence officials during the audit.
The alternative option of a ready and proven US design, such as the 7,900 tonne Block IV Virginia-class SSN, would moreover likely present the project with the same supply and accreditation bottlenecks currently endangering AUKUS, or potentially exacerbate those factors – an issue previously identified by former US Secretary of Defense Lloyd Austin.
In addition, the site identified for construction, Hanwha’s US based Philadelphia shipyard, does not currently produce submarines or nuclear powered vessels, being mainly configured for commercial vessels and the US Maritime Administration’s (MARAD) National Security Multi-Mission Vessel (NSMV) maritime training vessel.
Japan's response
Trump’s decision to permit the ROK to acquire an SSN capability has also intensified debates in Japan, whose ruling coalition have agreed to commit to the procurement of a vertical-launch missile (VLS) attack submarine featuring an as-yet unidentified “next generation propulsion technology.”
Former Japanese Chief of Staff Katsutoshi Kawano recently said that a likely result of Seoul pursuing a SSN capability would be an esclatory response from Pyongyang, on account of which “discussions on developing nuclear submarines in Japan will also progress.”