North Korean nuclear reactor at the country’s Yongbyon complex appears to be operating for the very first time

The Yongbyon complex in North Korea is believed to be operating a nuclear reactor for the first time, potentially serving as an additional source of plutonium for the country’s nuclear weapons program, according to the United Nations nuclear watchdog and independent experts. The International Atomic Energy Agency (IAEA) reported that warm water discharges observed from a larger light-water reactor at Yongbyon suggest it is now operational, marking the initiation of a self-sustaining nuclear chain reaction.

North Korea had been using spent fuel from a 5-megawatt nuclear reactor at Yongbyon to produce plutonium for its nuclear arsenal. However, the discharge of warm water from the larger light-water reactor indicates a new development. The IAEA, which lost access to North Korea in 2009 when Pyongyang expelled its inspectors, now relies on satellite imagery to monitor the country.

IAEA chief Rafael Grossi emphasized the challenge of confirming the operational status of the reactor without on-site access. He stated that the agency had observed a significant outflow of water from the light-water reactor’s cooling system since October, indicating ongoing commissioning.

The James Martin Center for Nonproliferation Studies in California and the Institute for Science and International Security in Washington, D.C., independently corroborated the IAEA’s findings. The latter estimated that the light-water reactor could potentially contribute to a significant increase in plutonium quantities, at a rate four to five times higher than the small adjacent reactor.

The development is a cause for concern, as plutonium produced in the light-water reactor can be separated during reprocessing, contributing to North Korea’s nuclear weapons program. The country’s nuclear activities have been a point of international concern, with multiple United Nations Security Council resolutions banning such programs. The latest observations underscore the need for continued monitoring and diplomatic efforts to address North Korea’s nuclear ambitions.