Simplified cutaway of Germany's HDW U-214 AIP (designated KSS-II by South Korea). South Korea has announced it will order/build a new batch of 6 AIP KSS-IIs.
Separatly South Korea (hereinafter called "Korea") is planning its much larger future conventional submarine (KSS-III). A project of interest to Australia.
Korea plans to design and build the KSS-III locally. It will be perhaps twice the size of the current KSS-IIs (1,700 tom surfaced). Australia went through similar exercises to build the Collins Class. The KSS-III will involve some advanced design and world renowned Korean production solutions of particular interest. The first KSS-III will also be built (launch date 2022) slightly ahead of Australia's future submarine (likely launch date 2027).
The increased tonnage of the future KSS-III suggests that Korea is looking at a larger AIP system or much longer range or a vertical launch system (VLS) (for first or second strike against North Korea using Hyanmoo III missiles) or a combination of the three.
Korea's main submarine opponent is almost certainly North Korea. As North Korea is a nuclear and conventional threat to Korea and a constant infiltrator though all media South Korea main submarine task would probably constant intelligence gathering - including detection of intruding North Korean submarines.
Korea's advanced nuclear power industry and the announcement that France is to assist Brazil in creating a nuclear powered Scorpene raises the possibility that Korea could go that way. Both Australia and Korea see China as a common opponent.
However only a nuclear powered submarine has the sustained speed to chase/shadow one of China's emerging SSBNs or SSNs. Cooperative tactics with US SSNs would therefore be essential.
Past Korean consideration of the nuclear propelled option
Treaty restrictions and political pressure from the US, Russia, Japan and China have probably been factors in preventing South Korea from developing submarine reactors or nuclear weapons. Yet if the US nuclear umbrella weakened South Korea may have little choice but to prepare the type of nuclear, last ditch, revenge weapons that Israel has had since the mid 1960s.
Delaying the KSS-III launch until after 2020 increases the possibility that nuclear propulsion might be adopted. Globalsecurity.com reports:
"In January 2004 Choson Ilbo journalist Yu Yong-won reported that South Korean military authorities were considering the possibility of developing nuclear powered submarines after 2012. South Korean officials began to discuss the construction of nuclear submarines in May 2003, to be able to deal with "potential security threats from other strong powers in the region following Korean unification."
The South Korean Navy was reported to have formed a working group of some 30 specialists to initiate design work on the project. In August 2004, reporter Kim Yong-sam of the South Korean monthly news magazine Wolgan Choson reported that the Ministry of National Defense had approved concept designs in June 2003. An inter-agency working group for the project was said to include the ROK Navy, the Agency for Defense Development (ADD), and the Korea Atomic Energy Research Institute (KAERI). According to one report, government officials stated that on 25 January 2004 Defense Department and the navy examined the construction of an atomic submarine positively, based on the report from May 2003. The nuclear propelled submarine of 4,000 ton class (SSX), after 2012, was said to be viewed positively in order for the Korean navy to cope with the threat in regard to the security of neighboring countries such as Japan and China.
Background on KSS-III Development
From The Korea Times, May 10, 2009 reports:
"The Ministry of National Defense plans to deploy 3,000-ton [surfaced, 3,500 ton submerged] attack submarines after 2020, a two-year delay from the original Defense Reform 2020 initiative, a report said Sunday. ...The development of an [indigenous] 3,000 ton KSS-III submarine is a key part of the Navy's modernization programs. The KSS-III sub is to be fitted with domestically built submarine combat systems aimed at automating target detection, tracking, threat assessment and weapon control, according to Navy officials. The 1-trillion-won heavy attack submarine will also be armed with indigenous ship-to-ground cruise missiles and be capable of underwater operations for up to 50 days with an advanced Air Independent Propulsion (AIP) system, they said. The AIP system has improved the submarine's underwater performance and gives it stealth capability." full article