South Korea's pursuit for nuclear-powered subs has gained traction after President Donald Trump's approval. This ends decades of U.S. opposition in a move which could reshape Asia’s security landscape, and escalate an undersea arms race. Seoul has sought to be part of the elite group that operates nuclear submarines in order to counter North Korea for many years. Trump's approval of the nuclear agreement between South Korea and North Korea removed a major barrier.

Analysts and former military officials believe that South Korea's rapidly evolving programme could still irritate China and force Japan to develop similar abilities.

Submarines can be highly effective as attack systems. Choi Il is a retired South Korean Navy sub captain. He said that an arms race was inevitable in the region. Seoul says nuclear propulsion will be crucial in countering North Korea's threats under the sea, such as submarine-launched missiles. It has said repeatedly that it will not obtain nuclear weapons and respects non-proliferation.

On Wednesday, South Korean President Lee Jae Myung described the agreement as a major accomplishment from his meeting Trump. He said that it would increase security flexibility and autonomy.

North Korea has claimed to be developing similar capabilities. State media showed Kim Jong Un inspecting a submarine that it claimed was nuclear-powered in March. Analysts are unsure of how far Pyongyang's programme has progressed, but the South Korean military says it closely monitors this possibility. Russia and North Korea both claim to be stepping up their defence cooperation but they haven't provided any details about technical defence cooperation.

COUNTERING CHINA

Yu Yong Weon, a South Korean defence expert and lawmaker, said that nuclear-powered subs would be able to better monitor North Korean submarines because they are faster, can stay underwater longer and are more powerful than diesel-powered counterparts.

Yu said that the acquisition by Seoul could also force Japan to reconsider its position.

Tokyo was surprised to hear that Trump supported Seoul's program, believing Japan would have been ahead of South Korea if the U.S. had backed such a programme in the region.

The Japanese Defence Ministry refused to comment. Shinjiro koizumi, Japan's Defence Minister, recently stated that nuclear propulsion is an option. However the ministry claimed no studies are currently being conducted. If Tokyo pursues nuclear submarines it will seek the U.S.' help, according to a Japanese official.

A Tokyo-based naval specialist, who requested anonymity because the subject is sensitive, stated that Japan's diesel-powered submarines are best suited for shallow water, but nuclear-powered submarines would allow operations to extend into the Pacific, and pave way for future second-strike capabilities.

South Korea's goals are in line with U.S. efforts to counter China's influence. U.S. Admiral Daryl Caudle, Chief of Naval Operations for the United States, described China as "a pacing threat". He said that South Korea's nuclear submarines will play a role in deterring China in the future.

North Korea warns of "Nuclear Domino"

38 North, a Washington-based thinktank, warns that this could quickly change.

Wi Sung Lac, South Korea's National Security Advisor, said that President Lee assured Chinese president Xi Jinping, last month, that the submarines will be defensive and deter North Korea.

We have our own position. Wi stated, "We can explain and convince."

North Korean state-run media warned that Seoul’s submarine plan might trigger a “nuclear cascade” effect.

Cheong Seong Chang, a researcher at the Sejong Institute think tank, has suggested that Japan and South Korea could jointly develop nuclear subs with U.S. assistance, aligning themselves with Washington's interests in regional security.

A LONG-STANDING DREAM?

Only the United States, Russia, China France, India, and the United Kingdom possess nuclear submarines. Australia plans to build a nuclear-powered submarine fleet with the help of the U.S., Britain and France under the AUKUS 2021 agreement.

The Sejong Institute reported that South Korea explored the idea for the first time in 1994, during the crisis surrounding North Korea's nucleonic programme. However, technical issues stalled the progress.

Two sources familiar with the situation said that in 2017, Moon Jae In, then president of South Korea, sought Trump's support for nuclear subs. Trump gave it to him privately. Sources said that some U.S. officials were opposed to the idea of a concrete support.

Choi Jong-Kun, a former vice foreign minister who served under Moon's leadership, claimed that U.S. departments like defence and energy expressed concerns about nuclear proliferation.

"TRAIN IS ALREADY MOVING"

According to retired Navy colonel Moon Keun Sik, who cited military sources, South Korea, despite setbacks, has made progress in developing basic designs of submarines.

Defence Minister Ahn Gyu back said that reactor assembly is at a "significant stage" and estimated Seoul can build a vessel in 10 years. At least four nuclear submarines weighing 5,000 tonnes are needed.

The joint U.S. South Korean fact sheet, published on November 14, indicated that Washington had agreed to collaborate on the sourcing of nuclear fuel.

Ahn, a member of the parliament, said: "Rather than call it approval (from America), we can claim that we already prepared the conditions for building nuclear-powered subs and that the fuel was the last piece we needed."

The defence ministry said that South Korea "continuously acquires" technologies for the construction of its nuclear submarines.

It said that it would work with the U.S. to improve the safety of its technologies.

A White House official stated that the United States supports South Korea in its efforts "to increase burden-sharing and deter threats against our alliance", including through developing nuclear-powered submarines. The AUKUS agreement with Australia helped Seoul lower its barriers, according to former Vice Minister Choi.

"The train has already started moving. The door is left open. This means that we still have work to do, but the train is on its way." Reporting by Jumin Park and Joyce Lee from Seoul, Trevor Hunnicutt from Washington, and Tim Kelly from Tokyo. Editing by Ed Davies & Lincoln Feast.

(source: Reuters)