S. Korea's nuclear-powered submarine program poses no proliferation concerns: IAEA chief

VIENNA, June 8 (Yonhap) -- South Korea's planned nuclear-powered submarine program should not raise proliferation concerns given that a solid and specific safeguards arrangement will be concluded with the International Atomic Energy Agency (IAEA), the agency's chief said Monday.

IAEA Director General Rafael Grossi noted Seoul and the IAEA have already begun such discussions, though they are still in a preliminary stage, due largely to the lack of specific details for Seoul's envisioned submarine program.

"As you know, in order to do that (build nuclear-powered submarines), countries that are party to the Nuclear Non-Proliferation Treaty (NPT) ... have to notify the IAEA, and for this to happen, there has to be a special arrangement with the IAEA," Grossi told a press conference here in Vienna.

"So we are in the face of the kickoff ... of that process, which is a highly technical process where our safeguards experts meet with Korean experts and they start looking at what will be necessary," he added.

His remarks come as South Korea is pushing to build conventionally armed, nuclear-propelled submarines following security agreements reached in a summit between President Lee Jae Myung and U.S. President Donald Trump in October.

"Insofar as you have a very solid agreement with the IAEA, there shouldn't be any proliferation concerns," Grossi said, when asked if the IAEA had any proliferation concerns over Seoul's proposed submarine program.

International Atomic Energy Agency Director General Rafael Grossi speaks at a press conference in Vienna on June 8, 2026. (Yonhap)

Grossi noted that the main technical challenge is ensuring accountability for nuclear material once it is loaded into submarines, which can operate underwater for extended periods outside routine inspection.

"So we need to find technical ways to ensure that the amount of uranium that left harbor is the same when it comes to," the chief said. "It is going to take a long time precisely to ensure that there is no proliferation."

Grossi stressed that discussions between Seoul and the IAEA are at a preliminary stage, noting that South Korea has not yet made final decisions on the type of technology or operational modalities involved in the project.

"This must be very specific because it will depend on the type of submarines that you are going to be building, how they are going to be designed, what kind of fuel there is going to be on it, what kind of infrastructure onshore you're going to have," he said.

Following the October summit, Seoul and Washington released a joint fact sheet, where