Jeffrey recently took a break from listening to U2 and put up “a couple of”:http://www.armscontrolwonk.com/1415/the-incredible-shrinking-heu-programf “great posts”:http://www.armscontrolwonk.com/1418/size-matters about the North Korean HEU issue. Since he saved me a bunch of work, I can focus on another aspect of this, um, thing.
Following on Jeffrey’s discussion of unacknowledged reporting, Mark Hibbs (unsurprisingly) has turned out some excellent work on the subject. For example, in the 11/25/02 edition of _Nuclear Fuel_, Hibbs reported on the “November 2002 CIA assessment”:http://www.fas.org/nuke/guide/dprk/nuke/cia111902.html of North Korea’s nuclear capabilities.
[ *Update:* Full text is now in the comments.]
You will recall that, “according to the CIA,”:http://www.fas.org/nuke/guide/dprk/nuke/cia111902.html the United States
…did not obtain clear evidence indicating the North had begun constructing a centrifuge facility until recently. We assess that North Korea embarked on the effort to develop a centrifuge-based uranium enrichment program about two years ago.
* Last year the North began seeking centrifuge-related materials in large quantities. It also obtained equipment suitable for use in uranium feed and withdrawal systems.
* We recently learned that *the North is constructing a plant that could produce enough weapons-grade uranium for two or more nuclear weapons per year when fully operational — which could be as soon as mid-decade.*
Hibbs’ reporting on the assumptions underlying that assessment makes for interesting reading.
p=. *GETTIN’ HELP*
According to the piece, the CIA estimate
…*presupposes [sic] that Pyongyang has obtained unprecedented assistance from foreign sources in building gas centrifuges, plus a complete design package for a proven subcritical centrifuge using aluminum,* Western government officials and enrichment experts told _Nuclear Fuel_.
U.S. officials have said assistance has been provided, and that they have identified its sources. For diplomatic reasons, the U.S. has not publicly revealed the sources.
Western officials told _Nuclear Fuel_ last week that *the CIA assessment presumed that North Korea obtained a vast amount of outside help* and, said one, *with a very high probability the aid included the complete design package for a proven machine. The assessment has the DPRK beginning large-scale centrifuge production in 2001 and producing an HEU significant quantity by 2005.*
This strongly suggests to me that there mighta been some worst-case scenario assumptions that went into that estimate. Ditto for the assumption that the Norks were hella faster at mastering HEU production than a lot of their peers (to the extent that the DPRK has peers these days):
The description of the DPRK program as going from raw centrifuge-building materials to HEU production *in just six years would represent a _dramatic telescoping of the timeline_ for less-developed countries to obtain nuclear weapons material using twice as much time and expending far more financial resources.* [Emphasis mine.]
To be fair, there is evidence, according to Hibbs’ sources, that “individuals with years of experience inside Pakistan’s uranium enrichment program” gave North Korea a serious amount of assistance, including “the design package for an aluminum centrifuge, prototype components, and manufacturing and some diagnostic assistance, which might dramatically reduce the timeline for the DPRK to enrich uranium.”
p=. *CUTTIN’ CORNERS*
The CIA’s timeline apparently also assumed that North Korea would be willing to cut some corners by, for example, installing centrifuges that had been pre-assembled in Pakistan:
Western officials and experts said it would certainly be technically feasible for Pakistan to have manufactured a few thousand complete rotor assemblies and to have brought machines to the DPRK for assembly. However, for reasons of efficiency it is preferable to assemble machines on site. *The DPRK might have brought to the erection site centrifuges pre-assembled save for the positioning of the bottom bearing, experts said, but pre-assembly would imply that scoops inside the rotor tubes would be out of place, that many machines would fail initially, and that many more would crash prematurely during operation.*
Sources said that *because the DPRK wants to enrich uranium to weapons-grade as fast as possible, it probably would make such sacrifices.*
I’m not sure the US IC has evidence that Pakistan ever provided assistance on that scale. In any case, the estimate for the enrichment plant assumes that
bq. …the DPRK was willing to take decisions and shortcuts which would mean that the initial failure rate of the machines might be as high as 10% and that ”after two or three years of operation, a very large number of machines would crash.”
This scenario takes the Pakistani experience into account, according to Hibbs’ sources, who said that Islamabad had lots of centrifuges fail during the first five years of the enrichment program. However,
bq. ”…they had made enough HEU for a one or two weapons by then.” *Given that the DPRK’s priority would be to acquire nuclear weapons capability as fast as possible using U-235, Pyongyang would be expected to also go down that path,* experts said.
So it appears that the estimate has its origins in some procurement information, some evidence of foreign assistance, and a lot of supposin’.