In this APLN Special Report titled “Prospects for DPRK’s Nuclear Use Scenarios and Deterrence Measures of the US and ROK Alliance,” Professor Lee Sangkyu, Republic of Korea army officer and assistant professor at the Korea Military Academy, investigates possible nuclear use cases by the DPRK based on its nuclear capabilities and nuclear strategy.  

The relative priorities and feasibility of the different DPRK nuclear use cases were analyzed using parameters evaluating their military effect, the potential for US nuclear retaliation, and the level of civilian casualties. The four most probable cases are analyzed as follows: 

The most probably case is an attack on the ROK Army Mobile Corps directly in the northern region of Gyeonggi-do with a nuclear weapon of 10-20 kt. The DPRK may intend to end the war early in an advantageous situation by disabling the main force of the ROK military forces and thus make ROK counter-attack operations impossible. It is expected that the nuclear attack will cause direct damage to personnel and equipment, and consequent loss of combat power. In addition, northern Gyeonggi-do and parts of Gangwon-do will be contaminated with fallout. 

The second most probable case is a wide range damage from an EMP caused by a high-altitude nuclear explosion near the DMZ at the beginning of the war. If the DPRK detonates a 20 kt yield nuclear weapon at an altitude of 60 km using a ballistic missile such as the SCUD or KN-23, the surrounding region, including Seoul, will be affected by an EMP. The DPRK’s intention might be to cause social chaos by neutralizing the national core infrastructure in Seoul, as well as to neutralize the command and communication system of the ROK military. 

In the third and fourth most probable cases are attacks on the Jinhae Naval Base and the port of Busan respectively. Because of the geographical closeness of Jinhae and Busan, these two cases differ depending on whether it is a direct nuclear attack or a situation in which only EMP is induced by detonating a nuclear weapon at an altitude of 50 km. In both cases, however, the DPRK’s intended purpose is to delay the deployment of the US mainland reinforcements and UN forces entering through major ports and to incapacitate the ROK’s core national infrastructure, because Busan is the second largest city of the ROK. Through this, the DPRK will try to end the war prematurely by weakening the ROK’s ability to sustain the war.  

Within that case, there is a danger of nuclear provocation due to the asymmetry between the DPRK’s nuclear possession and ROK’s possession of only conventional forces. Therefore, the author emphasizes the importance of the US extended deterrence policy in ROK to deter the DPRK’s nuclear threat. 

This report is a part of a joint project on Reducing the Risk of Nuclear Weapon Use in Northeast Asia (NU-NEA) and has been cross-posted by the Nautilus Institute, the Research Center for Nuclear Weapons Abolition (RECNA), and the Panel on Peace and Security of North East Asia (PSNA). The year 1 final report of the project is now available here.

About the Author

Lee Sangkyu is a Republic of Korea (ROK) army officer and assistant professor at the Korea Military Academy (KMA). His main research focus is the Democratic People’s Republic of Korea’s (DPRK) nuclear threats, including its nuclear capabilities, strategies, and command and control system. Professor Lee holds PhD and MS degrees in Nuclear Engineering from the University of Utah in the United States. He has been an assistant professor in the Department of Physics at KMA since 2019, and from 2017 to 2018 served as the Nuclear Policy Planning Officer at the North Korea Policy Bureau, Ministry of National Defense, Republic of Korea.

Disclaimer: This article reflects the personal opinions of the author, not the official opinions of the government of the Republic of Korea. The views expressed in this report do not necessarily reflect the position of the Asia Pacific Leadership Network or any of its members.

Image: Alex Sholom