By Yi Whan-woo



South Korea has already drawn up a preliminary sketch of a reactor for a 4,000-ton nuclear-powered submarine, according to military officials, Sunday.



The Moon Jae-in administration is seeking negotiations with Washington to build the country's own nuclear-powered submarines in line with a push to bolster military capabilities for self-defense and better cope with North Korea's evolving nuclear threats.



The officials said scientists at the Agency for Defense Development, which is under the wing of the Ministry of National Defense, already finished the design for a nuclear reactor three years ago.



This suggests the military is ready to create a nuclear submarine prototype if the Moon government completes the negotiations with the United States.



"The country is virtually ready to work on the detailed design of the reactor and make it once relevant policies are finalized," an official said. "Production is estimated to take three to five years. It will require consent from the U.S. on having South Korea use uranium enriched up to 20 percent as the source for the submarine's reactor."



Uranium enriched to less than 20 percent is considered "low enriched uranium."



The Navy had worked on a nuclear submarine program, the "362 Project," after it was approved by then-President Roh Moo-hyun in June 2003.



It was aimed at converting the system-integrated modular advanced reactor (SMART) for operation of a submarine. SMART is a small integral reactor for industrial purpose.



The project was suspended in 2004 due to concerns, both domestic and international, over the possible construction of a nuclear-powered submarine.



But the Agency for Defense Development separately worked on converting SMART for military use.



Some military sources said Moon, who was Roh's chief of staff, appears to have the desire to revive Roh's pursuit of nuclear submarines.



Concerns have grown sharply over South Korea's capability to counter North Korea's submarine-launched ballistic missile threats.



The Navy only operates 1,200 ton Type 209 diesel-electric attack submarines, and the Type 214 sub, an improved version of the 209.



Both need to surface frequently to access air, raising the possibility of them being detected by the enemy.



On the other hand, a nuclear-powered submarine can operate underwater almost unlimitedly as long as other conditions such as food supply are met.



Building a nuclear submarine, however, requires a revision of the bilateral nuclear agreement reached between South Korea and the U.S.



Last revised in June 2015, the deal extended South Korea's use of enriched uranium for a stable supply of fuel but still restricts the country from using it for other than commercial purposes.



Only six nations -- the U.S., Russia, Britain, France, China and India -- have their own nuclear-powered submarines.











