North Korea's denuclearization, if agreed to, would involve four major steps, including a declaration of its nuclear stockpiles, experts said, as U.S. President Donald Trump and North Korean leader Kim Jong-un are set to begin a two-day summit on Feb. 27, 2019.
At their meeting in Hanoi, Vietnam, the leaders are expected to focus on fleshing out the vague agreement on the "complete denuclearization" of the Korean Peninsula that they signed in their first meeting in Singapore in June.
A standard denuclearization process starts with the closing of nuclear facilities, such as reactors and spent fuel reprocessing factories.
The first step entails measures to temporarily shut down nuclear facilities, seal them and install monitoring equipment to prevent any unauthorized access to them, or freeze all nuclear operations.
Then comes the second phase of declaration and verification.
At this phase, Pyongyang is to be required to make a full declaration of its nuclear facilities, materials, weapons and other equipment, which will be followed by procedures to verify the "correctness and completeness" of its nuclear inventory declaration.
The third step is disablement, which entails separating some components of key nuclear facilities and putting them in other locations, or destroying them -- while keeping their overall exteriors intact -- so as to ensure that they are inoperable for a certain period.
It is usually a temporary step before the ultimate disintegration or dismantlement of the facilities.
The final step is dismantlement. It involves a series of procedures to decommission, decontaminate and dispose of all declared nuclear facilities, materials, equipment and other related items.
Following the disablement phase, the North can decommission its nuclear facilities, such as reprocessing and nuclear fuel production factories, immediately if the process does not pose any risks of radioactive contamination.
Should there be contamination risks, one can wait until amounts of radioactivity go down to a safe level. This is called "deferred decommissioning."
Under a 1994 deal between Washington and Pyongyang, the communist state took steps to freeze its 5-megawatt reactor and the reprocessing facility at its main Yongbyon nuclear complex. But it failed to take additional steps as the deal collapsed in 2002 following revelations that it had a covert uranium enrichment program.
Following a 2005 deal from the six-party talks, involving the two Koreas, the U.S., China, Japan and Russia, the North took reversible steps toward disablement but did not move beyond that phase.
At the Hanoi summit, the North may agree to dismantle its mainstay nuclear complex in Yongbyon, which is now home to some 400 buildings. The complex houses a 5-megawatt reactor, spent fuel reprocessing facilities, and research and uranium enrichment buildings among others.
During his third summit with South Korean President Moon Jae-in, Kim agreed to permanently dismantle the complex should the U.S. take corresponding measures, possibly including sanctions relief and security assurances.
Experts here said the Yongbyon dismantlement would serve to prevent the North from producing additional fissile material and would mark a meaningful step toward complete denuclearization. Skeptics, however, said the disposal of the decadesold complex would not eliminate the North's military threats.
Pyongyang is known to possess some 50 kilograms of weapons-grade plutonium after reprocessing spent fuel rods at least four times since 2002. About 6 kilograms of plutonium is required to build a single bomb.
The North is also thought to have a considerable amount of highly enriched uranium, according to South Korea's 2018 defense white paper. (Yonhap)