Japan Institute for National Fundamentals

　
North Korean leader Kim Jong Un inspected an “important shipyard” to check the construction of a “nuclear strategic guided missile submarine,” according to the Rodong Sinmun, the official organ of the ruling Korean Workers’ Party, and other North Korean media on March 8. North Korea has set a goal of building a nuclear-powered submarine in a five-year national defense plan adopted at the 2021 KWP Congress. Media reports included photos of what appeared to be a nuclear submarine under construction.

If North Korea possesses a nuclear submarine equipped with nuclear missiles, it will be able to launch a nuclear attack on the U.S. mainland without using intercontinental ballistic missiles (ICBMs). Even if ground-based nuclear missiles are destroyed by South Korean forces, North Korea will be able to nuke South Korea from nuclear submarines. North Korean nuclear submarines will be a threat that can change the strategic balance over the Korean Peninsula.

Using technology stolen from Russia

Let me share the latest information I received about the progress in nuclear submarine construction and how North Korean obtained necessary technologies. According to the information, the place Kim inspected is the Cheongjin Shipyard, not the Sinpo Shipyard that has traditionally built submarines. The construction of a 10,000-ton class nuclear submarine has recently begun at the Cheongjin Shipyard that was said to have been chosen because of its proximity to the Russian border.

However, North Korea did not officially receive nuclear submarine technology from Russia in return for the dispatch of North Korean troops to the war in Ukraine. Kim originally asked Russian President Vladimir Putin to provide North Korea with a used nuclear submarine. However, Putin rejected the request for the reason that special technology and money would be required to control used nuclear submarines of which accidents would cause serious damage. Putin then offered to sell a new nuclear submarine if Kim wanted to buy one. Because the new one was quite expensive, however, Kim decided that his country could not buy new one due to a lack of foreign currency reserves. So, North Korea decided to buy over Russian nuclear submarine engineers individually and steal Russian technology.

Before the Ukraine war, seven to eight North Korean spies were arrested for trying to steal Russian nuclear submarine technology. At the time, the Russian government was cracking down on the North Korean spies’ access to military technology. The North Korean spies were released in the wake of Kim’s visit to Russia for a meeting with Putin in 2023. Against the backdrop of the recent improvement in North Korea-Russia relations, Russian engineers have come to believe that they would not be severely punished for smuggling technology to North Korea. North Korean spies have taken advantage of such situation to obtain nuclear submarine technology from Russian engineers.

Small nuclear reactors may yet to be obtained

Since North Korea cannot produce special steel plates required to build nuclear submarines, it has smuggled them from Russia. It seems that North Korea has yet to obtain technology for manufacturing and controlling small nuclear reactors to power submarines. Therefore, it is not known when the nuclear submarine carrying nuclear missiles will be completed. It is necessary to continue to monitor developments.

North Korea’s announcement of the nuclear submarine construction at this time could be related to Kim’s desire to negotiate with U.S. President Donald Trump soon. He might have sent a message to Trump: Pay attention to me quickly. Threats will increase if you leave me untouched.

Tsutomu Nishioka is a senior fellow and a Planning Committee member at the Japan Institute for National Fundamentals and a specially appointed professor at Reitaku University. He covers South and North Koreas.