Last week, David Albright and Paul Brannan of ISIS published a DigitalGlobe image showing new construction in the area of the demolished cooling tower of the 5 MW(e) reactor at Yongbyon. They were circumspect in their analysis, concluding only that “the actual purpose of this excavation activity cannot be determined from the image and bears watching.”

John Pomfret has rounded up a couple of equally cautious expert judgments for today’s Washington Post. It could be preparation for a new cooling tower and a restart of the reactor, or — according to Joel Wit — it could be merely “for show, to pull our chains.” Jonathan Pollack — the man we call Pollack the Elder — commented that it’s not clear what’s being done, “but any new construction at Yongbyon cannot be a good thing.”

All of these observations are (so I believe) basically true. But with due respect to those named above, I think we can make a pretty good guess about what’s happening.

The most likely purpose of construction on the site of the old cooling tower is… a new cooling tower. And at the same time, it’s almost certainly “for show, to pull our chains.” But not just for show.

It’s Bolsterin’ Time

For the past year or so, North Korea has been trying to draw the United States into talks on Pyongyang’s terms, with an emphasis on concluding a peace treaty over a quick return to denuclearization. With one hand, North Korea offers a return to the Six-Party Talks; with the other, they threaten to “strengthen” or “bolster up” their “nuclear deterrence.” As the main visible sign of restoring the reactor, a new cooling tower would be a… well, concrete manifestation of that threat, lending it much more credibility than words alone: restarting the reactor means making more plutonium.

A quick review of the ISIS report or a visit to Google Earth will show that there’s plenty of room around the Yongbyon complex to build, and I can’t think of any special reason to put something other than a new cooling tower on the location of the old one. What’s more, putting something else there would complicate any later attempt to get the reactor working again — which would undercut the threat to “bolster up the deterrent.” In effect, it would be an additional and unilateral disablement step, which has not been the North Korean style to date.

(Of course, it’s possible to put a new cooling tower in another spot nearby, but that would require re-routing the cooling circuit. Nor is it clear that it’s possible to use the nearby Kuryong River for cooling instead, as it appears to drop to low levels in the winter. This happens to be visible in the current picture in Google Earth, dated February 20, 2007 — much of the riverbed at the bend by the reactor is exposed. Roads laid on the riverbed, apparently to facilitate ice harvesting, suggest that it had been that way for some weeks or months, too.)

What the DigitalGlobe image appears to show, above all, is a serious challenge to the doctrine of “strategic patience.” The danger, now, is that the Obama Administration will simply dig in its heels, rather than finding a creative bridging formula to enable a return to the Six-Party Talks. That’s probably the opposite of what Pyongyang is trying to achieve, but it wouldn’t be the first time that “carrots and sticks” — or as we now say, a two-track policy — didn’t quite perform as hoped or intended.

Related: a discussion of rebuilding the cooling tower, from back in March.

Update. Somehow — don’t ask how! — I forget to reference this post.

Late update. GlobalSecurity.org has a presentation of the same imagery.