"Though we have acheived progress, our work is not over. That is why I support the mission of the Arms Control Association. It is, quite simply, the most effective and important organization working in the field today." 

– Larry Weiler
Former U.S.-Russian arms control negotiator
August 7, 2018
NK Delivers Plutonium Documentation

Peter Crail

U.S. officials May 8 obtained documents detailing the operating records of North Korea's key plutonium-related facilities at Yongbyon. Examination of the records would provide some indication of the amount of plutonium that the facilities produced and separated for potential use in Pyongyang's nuclear weapons program. This plutonium is suspected to have been used for any nuclear weapons produced by North Korea, including the nuclear device the country detonated in October 2006.

Although it is unclear how much plutonium North Korea separated before these facilities were shut down in 2007, the U.S. intelligence community has reportedly increased its estimate of the amount of Pyongyang's plutonium stockpile. North Korea's plutonium declaration and the amount of plutonium suggested by the records and follow-up verification is likely to be measured against this estimate.

Accounting for Pyongyang's Plutonium

North Korea provided about 18,000 pages of operating records to a U.S. delegation led by Sung Kim, director of the Department of State Korean affairs office in the Bureau of East Asian and Pacific Affairs. The records contain the daily operational logs, production notes, and receipts of two key facilities at the Yongbyon nuclear complex-a five-megawatt nuclear reactor and a reprocessing plant-since they began operations in 1986.

The nuclear reactor produces spent fuel, which contains plutonium. The reprocessing facility chemically separates the plutonium from this spent fuel, allowing this fissile material to be used in nuclear weapons.

Kim told reporters May 13 that "it will take some time" to translate the documents but noted that he expects a "preliminary review in a few weeks."

The reactor documents are only one component in an effort to verify North Korea's plutonium-based weapons program. Following a visit to the Yongbyon facilities earlier this year, Siegfried Hecker, former head of Los Alamos National Laboratories, said April 30 that it is possible through verification to achieve a "high degree of confidence" regarding the amount of plutonium that North Korea produced "if North Korea cooperates." He noted that this cooperation would need to include access to the fuel waste to determine its isotopic composition and to the facilities' processing systems and equipment in order to determine how much plutonium remained stuck in them.

Kim indicated May 13 that, during his discussions with North Korean officials the previous week, Pyongyang "agreed to fully cooperate with verification activities." He added that the verification procedures themselves would be subject to negotiation in the six-party talks.

Prior to the negotiations over verification, North Korea is expected to provide its own accounting of how much plutonium it produced and separated since 1986. As part of a February 2007 agreement of the six-party talks involving China, Japan, North Korea, Russia, South Korea, and the United States, Pyongyang pledged to provide a complete and correct declaration of all of its nuclear activities. (See ACT, March 2007. )

In April, Assistant Secretary of State for East Asian and Pacific Affairs Christopher Hill reportedly reached a compromise agreement with North Korea that would entail a formal declaration of Pyongyang's plutonium program and recognition of U.S. concerns regarding two additional key issues, a suspected uranium-enrichment program and alleged nuclear proliferation to other countries, including Syria. (See ACT, May 2008. ) Hill told reporters May 19 that the negotiations are "getting to the point where the declaration is coming."

North Korea discussed the contents of its declaration with U.S. officials in November 2007 and declared that it produced about 30 kilograms of plutonium. Hill indicated in Feb. 6 testimony to the Senate Foreign Relations Committee that this declaration was "on the low end" of estimates. If North Korea was able to produce more plutonium than the verification mechanisms were able to account for, Pyongyang might still be left with enough material to secretly produce a small number of additional nuclear weapons.

Moreover, U.S. intelligence agencies appear to have raised the bar for the amount of plutonium for which North Korea is expected to account. The Washington Post reported May 13 that the United States has increased its estimates of North Korea's stockpile of plutonium. The new estimates reportedly range from a baseline of about 35-40 kilograms to a high end of about 50-60 kilograms, enough for up to 15 nuclear devices.

Such estimates indicate an apparent increase of about 10 kilograms more than the previously estimated ceiling, although it is not clear why the estimate would have risen. An Aug. 8, 2007, unclassified intelligence report to Congress on North Korea's nuclear and missile capabilities stated that Pyongyang "could have produced up to 50 [kilograms] of plutonium" prior to its 2006 nuclear test. It is unknown how much plutonium North Korea used in the test.

Disablement on Final Steps

Meanwhile, a May 10 State Department fact sheet indicates that eight of the 11 disablement steps to which the six parties agreed in November 2007 have been completed. The remaining three steps include finishing the discharge of 8,000 spent fuel rods still in the reactor; the removal and storage of the reactor's control rod drive mechanisms; and the bending of the fresh fuel rods from the fuel fabrication facility so that they cannot be used in the reactor.

North Korean technicians began to remove the spent fuel rods from the reactor at the end of 2007, but slowed removal from 80 rods per day to just 30 rods per day in response to delays in the delivery of energy assistance to North Korea by other parties in the talks. Patricia McNerney, State Department principal deputy assistant secretary for international security and nonproliferation, told a National Defense University audience May 8 that the unloading of the spent fuel was more than one-third complete.

The removal of the control rod mechanisms will be carried out once all the spent fuel rods have been discharged from the reactor. The six parties have yet to determine, however, what they will do with the spent fuel once it has been discharged and sufficiently cooled. Following the experience with the 1994 U.S.-North Korean denuclearization agreement in which Pyongyang's spent fuel was kept in North Korea and reprocessed for potential use in nuclear weapons when the deal collapsed after 2002, the United States does not consider keeping the current batch of spent fuel in North Korea a viable option.

Uncertainty also remains regarding the remaining step of disabling the fresh fuel rods, as North Korea has not yet agreed to carry out this process. Hecker noted April 30 that, although Washington considers this process one of its 11 steps, it was not identified as part of the disablement process by North Korean officials at Yongbyon.

A Department of Energy official told Arms Control Today in December 2007 that disabling the fresh fuel rods was a critical step because it would prevent North Korea from having an immediate source of fuel if the negotiations collapsed.