A US think tank suggested possible activity at North Korea’s key nuclear facility in Yongbyon, pointing to a satellite image showing steam coming out of its radiochemistry lab and thermal plant.

The Center for Strategic and International Studies published its analysis based on a satellite image dated Tuesday as the US government is wrapping up a comprehensive review of its North Korea policy.

In an article published on “Beyond Parellel,” a website run by the CSIS Korea Chair, former US national foreign policy adviser Victor Cha and CSIS imagery analyst Joseph Bermudez linked the activity at the nuclear facility to Pyongyang’s strategy to increase pressure on both Washington and Seoul.

“Probable reasons for this activity are preparations for, or the start of, a new reprocessing campaign, a strategic political move by Kim Jong-un to continue slowly ratcheting up pressure” on both the Joe Biden administration and the Moon Jae-in administration, they wrote.

The March 30 satellite image shows steam emitting from a small building within the Yongbyon lab and from its associated thermal plant, which follows activity previously observed at the thermal power plant during the past four weeks, they said.

The radiochemistry lab is used to reprocess spent fuel rods to extract plutonium for use in nuclear weapons.

Cha and Bermudez wrote that steam or smoke rising from any of the lab chimneys is not often observed in commercial satellite imagery.

Although the plume of steam or smoke doesn’t directly indicate a reprocessing campaign, it means that the building is occupied and being heated, they said.

Imagery also shows the storage pens at the thermal power plant have been field during the past two weeks, according to the CSIS article.

Cha and Bermudez added, however, that no activity of significance is noted to indicate that the experimental light water reactor, 5-megawatt reactor, IRT-DPRK reactor, the centrifuge plant or the center’s railroad yards are operational.

Another US research group called 38 North said last month that North Korea continued to run its uranium enrichment plant at the Yongbyon complex through the winter.

Satellite imagery of the area showed specialized railcars arriving and departing the area on a regular basis throughout January and February, 38 North said.

The railcars have been uniquely configured to carry cylindrical canisters, which could be containing chemical reagents, and arrive at the plant two or three times a year, 38 North said in its Feb. 19 report.

38 North continued to report signs of activity at Yongbyon nuclear center since, citing satellite imagery.

Against such a backdrop, US national security adviser Jake Sullivan is scheduled to host his South Korean and Japanese counterparts in Washington to discuss the outcome of the North Korea policy review later this week.

Since the US presidential election campaign last year, Biden has repeatedly stressed that he will not meet Kim Jong-un without any preconditions towards North Korea’s denuclearization.

The White House said Monday that Biden does not intend to meet with Kim.

By Kim So-hyun (sophie@heraldcorp.com)