Yongbyon

International Atomic Energy Agency chief Rafael Grossi said earlier the UN nuclear watchdog had observed activity consistent with the operation of a reactor and the reported centrifuge enrichment facility at Yongbyon.

The Soviet Union helped the newly founded Pyongyang regime in the 1960s in building its nuclear research facility at Yongbyon, which has played a key role in its six nuclear tests since 2006.

A minideal could involve any number of activities related to freezing or destroying fissile material and facilities, dismantling Yongbyon, or verifiably closing underground nuclear test sites and missile test facilities.

Going into the summit there were clearly gaps between the U.S. and North Korean positions on a deal trading dismantlement of Yongbyon for sanctions relief and not enough time to resolve them.

Ri also said that the regime had offered to dismantle plutonium and uranium processing at Yongbyon and allow U.S. experts to monitor this, if sanctions were partially lifted.

South Korean television shows footage of the public demolition of a North Korean cooling tower at the Yongbyon nuclear complex on June 27, 2008.

The North Koreans later contradicted Trump, saying they had demanded only a partial lifting of sanctions, but they confirmed that they had offered to dismantle their main nuclear site, at Yongbyon.

The scrapping of nuclear facilities, such as the Yongbyon complex, which has a graphite-moderated reactor, will come into focus in forthcoming working-level talks between Washington and Pyongyang.

The two sides have discussed partial denuclearization measures, such as allowing inspectors to observe the dismantlement of North Korea's Yongbyon nuclear reactor, U.S. and South Korean officials say.

Pyongyang also said it could dismantle its best-known nuclear facility at Yongbyon, if the US takes ‘corresponding measures’, as Kim and the South Korean president held their third summit this year.

The U.S. and North Korea in October 1994 agreed on the “framework” under which North Korea suspended its nuclear program and shut down its five-megawatt plutonium reactor at Yongbyon.

Although all these facilities at Yongbyon were to be under safeguards, there was always the risk that at some stage, the DPRK would withdraw from the NPT and use the plutonium for weapons.

Nuclear program 5 MWe experimental reactor at Yongbyon Nuclear Scientific Research Center main North Korea's nuclear research program started with Soviet help in the 1960s, on condition that it joined the Nuclear Non-Proliferation Treaty (NPT).

On February 13, 2007, North Korea signed an agreement with South Korea, the United States, Russia, China, and Japan, in which North Korea will shut down its Yongbyon nuclear reactor in exchange for economic and energy assistance.