Can South Korea develop its own nuclear submarine?

Dubbed the “362 initiative”, the programme was derailed just a year later, with classified information leaked to the public and its nuclear activity was brought under the scrutiny of the UN nuclear watchdog the International Atomic Energy Agency (IAEA). 
After 13 years, calls for building indigenous nuclear submarines are gaining momentum once again, this time in a more challenging security environment due to North Korea’s successful launches of intercontinental ballistic missiles (ICBM) 
and its nuclear programme. 
“We are ready to consider it,” said South Korea’s Minister of National Defence Song Young-moo said, three days after Pyongyang fired off an ICBM capable of reaching the contiguous US. 
Nuclear submarines have long been considered a prime component of deterrence and pre-emptive strike capability against Pyongyang’s nuclear threats, as they can operate deep into North Korean waters, monitor their nuclear and missile facilities and strike if an attack is imminent, analysts have said. 
Unlike South Korea’s conventional diesel-powered submarines, which have to surface for oxygen every three to four days, nuclear-powered submarines can engage in underwater missions for up to a year, unless they surface for their sailors and supplies. 
The need for a nuclear submarine has been amplified by North Korea’s accelerated efforts to diversify its platform to carry out ballistic missile attacks, experts said. 
“Nuclear-powered submarines are probably the only weapon systems that can impose retaliatory attacks after surviving the enemy’s pre-emptive strikes,” said Moon Geun-shik, a submarine expert and defence analyst at Seoul security think tank Korea Defence and Security Forum. 
“Compared to diesel-powered submarines, nuclear-powered submarines can provide much more advanced manoeuvrability and stealth capability. It is like putting a dagger in the enemy’s neck in a dark alley.” 
Analysts agreed that South Korea is considered to have secured technology for developing nuclear-powered submarines, as the country is able to build its own nuclear reactor and miniaturise it to fit into indigenous submarines. 
When the Roh administration launched the submarine programme, the then government anticipated that building one nuclear submarine would cost about 1.3 trillion won (Bt39 billion), about 1/40th of South Korea’s defence budget in 2017. 
“South Korea’s atomic energy agency finished its basic design for a nuclear reactor that can be used for a nuclear-powered submarine in 2004,” Kim Si-hwan, who was in charge of developing nuclear reactors for submarines at the Atomic Energy Research Institute, told local magazine Monthly Chosun. 
But the challenge is how to secure nuclear material for the submarines, a process that would involve massive imports from nuclear states and would therefore bring scrutiny from the IAEA and the Non Proliferation Treaty (NPT), which bans its non-nuclear member states from acquiring nuclear weapons. South Korea is a member state of the NPT. 
Currently, there are only six countries with nuclear submarines: the US, Russia, China, the United Kingdom, France and India. With the exception of India, which did not join the NPT, the other five countries are allowed to possess nuclear weapons under the NPT as permanent members of the UN Security Council.
Some analysts suggest that South Korea could avoid the international restriction by developing a nuclear submarine run by low-enriched uranium, which would not incur concerns over military use. Under an agreement with the US in 2015 on Seoul’s use of nuclear technology and materials, South Korea is allowed to enrich uranium up to 20 per cent, but is strictly banned from using it for any military purpose. “As the US, UK and other nuclear powers did when they mounted nuclear reactors on their nuclear submarines, we have to argue that we will use the nuclear material only for the submarines’ fuel and ... it is only designed for peaceful use,” expert Moon Geun-shik said.