On the 14th, through a joint fact sheet (joint explanatory material) with the United States, South Korea obtained broad U.S. consent related to the construction of nuclear-powered submarines and to authority for civilian uranium enrichment. The two countries are expected to determine concrete implementation methods and procedures through follow-up consultations. Another task cited is dispelling concerns within the United States and among neighboring countries regarding the nonproliferation regime.

In the fact sheet, the two countries stated, “The United States has approved South Korea building nuclear-powered submarines,” and, “To advance the requirements of this shipbuilding project, the United States will work closely with South Korea, including on fuel procurement options.” The presidential office said, “We have secured, for the first time, U.S. support for the construction of nuclear-powered submarines.” The fact sheet also states, “We support procedures that will result in civilian uranium enrichment and reprocessing of spent nuclear fuel for South Korea’s peaceful use.”

For the government to obtain from the United States the nuclear fuel to be used in nuclear-powered submarines, additional discussions are required, including concluding a separate agreement under the U.S. Atomic Energy Act. The U.S. Atomic Energy Act stipulates that, for nuclear cooperation with another country for military purposes, an agreement must first be concluded. Agreements related to the AUKUS partnership (AUKUS), under which the United States and the United Kingdom sell or support construction of nuclear-powered submarines for Australia, also proceeded accordingly. The consent of the U.S. Congress is also required.

Because the fact sheet does not specify where the nuclear-powered submarines will be built, this could become a point of contention between the two countries going forward. The government’s position is that discussions proceeded on the premise of construction in South Korea. If the United States later argues for construction in its own country, that could hinder progress in the consultations.

There is also the possibility that neighboring countries such as China, North Korea, and Russia will object, raising the question of how to respond. Since the 2021 launch of AUKUS, the Chinese side has raised the issue at forums such as International Atomic Energy Agency (IAEA) meetings, arguing that it runs counter to the spirit of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). Concerns have also been voiced that introducing nuclear-powered submarines could trigger an arms race in Northeast Asia. The government’s position is that the IAEA judged the AUKUS agreement not to violate the NPT, and that South Korea’s introduction of nuclear-powered submarines is necessary to respond to North Korea’s threat. The government is considering low-enriched uranium of under 20% as fuel for the nuclear-powered submarines, rather than uranium enriched to over 90% that can be used to make nuclear weapons.

Specific methods for South Korea to secure authority for civilian uranium enrichment and reprocessing are also absent from the fact sheet. The two countries appear likely to decide the related procedures first through follow-up consultations. The South Korean government has in mind amending the current nuclear cooperation agreement concluded in 2015. Under the agreement, South Korea can enrich uranium to below 20% and can also carry out reprocessing only with U.S. consent. The government’s goal is to obtain comprehensive U.S. consent, as Japan has, and thereby hold authority for enrichment below 20% and for reprocessing. Amending the agreement would likely require procedures for U.S. congressional approval.

There is also a method of securing authority through operation while maintaining the current framework of the agreement. If the two sides reach a written agreement after consultations through bodies such as the High-Level Committee, a vice-ministerial consultative mechanism, enrichment below 20% and nuclear fuel reprocessing are possible. However, there would inevitably be limits to securing substantive authority.

It is uncertain whether future discussions can proceed quickly and smoothly. The fact sheet includes the qualifier that this must be “within the scope of conforming to the Korea·U.S. nuclear cooperation agreement and complying with U.S. legal requirements.” This is interpreted as emphasizing that matters must proceed based on internal procedures, such as agreements under the U.S. Atomic Energy Act, rather than the United States granting South Korea an exceptional authority purely for political reasons. It can be seen as reflecting the U.S. view that securing, for example, enrichment authority for South Korea should not undermine trust in the nonproliferation regime.

The delay in announcing the fact sheet also stemmed from the protracted coordination process within the United States over enrichment and reprocessing issues. This suggests that there were opposing views within the United States in consideration of the nonproliferation regime. Addressing concerns within the United States is expected to be a key task for the South Korean government.