News Analysis: Examining North Korea's Nuclear Claims

March 2005

The North Korean Foreign Ministry’s announcement Feb. 10 that Pyongyang has “produced nuclear weapons” made front-page news around the world. Yet, whether Pyongyang actually possesses such weapons is unknown, although U.S. officials say that North Korea has programs to produce both plutonium and highly enriched uranium for use as fissile material in nuclear weapons.

The Foreign Ministry statement is Pyongyang’s most definitive public comment to date regarding its nuclear arsenal. However, North Korean officials have previously made similar public statements. For example, Pyongyang’s ambassador to the United Kingdom, Ri Yong Ho, said in a November 2003 interview with Reuters that North Korea possesses a workable nuclear device. (See ACT, December 2003.) Additionally, Vice Foreign Minister Choe Su Hon told reporters last September that Pyongyang had produced nuclear weapons.

A North Korean official told a U.S. delegation during an April 2003 meeting in Beijing that Pyongyang possesses nuclear weapons, the first time North Korea made such a claim. (See ACT, May 2003.)

Plutonium Program
The U.S. intelligence community first assessed during the 1990s that North Korea had one or two plutonium-based nuclear weapons, then-CIA director George Tenet told the Senate Intelligence Committee in February 2004.

According to an August 2003 CIA assessment, North Korea has “validated the [weapons] designs without conducting yield-producing nuclear tests.”

Tenet’s successor, former Rep. Porter Goss (R-Fla.), testified to the same committee Feb. 16 of this year that North Korea’s “capability” to produce nuclear weapons has since “increased.” U.S. intelligence agencies have a “range” of estimates on the size of North Korea’s arsenal, Goss said, but did not elaborate.

Assistant Secretary of State for Intelligence and Research Thomas Fingar offered a more cautious assessment of Pyongyang’s nuclear capabilities in a Feb. 16 statement to the same panel. There is “no evidence” that North Korea has produced nuclear weapons or “mated them to a missile capable of delivering them to the United States,” he stated.

The 1990s assessment is believed to have been based on estimates of the amount of plutonium North Korea separated before concluding the 1994 Agreed Framework with the United States. In that agreement, North Korea agreed to close operation of its nuclear reactor and related facilities. The International Atomic Energy Agency (IAEA) was charged with monitoring the freeze, as well as approximately 8,000 spent fuel rods.

The Agreed Framework broke down in October 2002. At that time, U.S. officials announced that North Korean officials had acknowledged a covert uranium-enrichment program during a meeting with a U.S. delegation, a claim that Pyongyang has publicly denied. After diplomatic tensions between the two countries escalated, North Korea ejected IAEA inspectors in December 2002.

Pyongyang later claimed to have reprocessed the spent fuel, which would have contained enough plutonium for “several more” nuclear weapons, Tenet said.

North Korea’s reprocessing claim apparently forms the basis for Goss’s statement regarding Pyongyang’s nuclear capabilities. Siegfried Hecker, a senior fellow at the Los Alamos National Laboratory, told the Senate Foreign Relations Committee in January 2004 that the fuel rods were no longer in storage when he visited North Korea earlier that year, but he could not verify North Korea’s reprocessing claim. (See ACT, March 2004.)

South Korea’s defense minister, Yoon Kwang-ung, told a National Assembly Committee Feb. 21 that North Korea has reprocessed “only part of the spent fuel rods,” Seoul’s semi-official Yonhap News Agency reported.

Hecker also testified that North Korean officials showed him a sample of what appeared to be plutonium metal, a material used to form the core of a plutonium-based nuclear weapon.

Uranium-Enrichment Program
The Bush administration asserts that North Korea has a gas-centrifuge-based, uranium-enrichment program. Gas centrifuges “enrich” uranium hexafluoride gas by spinning it at very high speeds to increase the concentration of the relevant fissile isotope.

February reports from the Washington Post and New York Times revived allegations that North Korea shipped uranium hexafluoride to Libya. Tripoli disclosed this material following its December 2003 decision to give up its nuclear weapons efforts, which included a uranium-enrichment program. (See ACT, July/August 2004.)

The IAEA reported in May that Libya ordered 20 metric tons of uranium hexafluoride from a proliferation network run by former Pakistani nuclear official Abdul Qadeer Khan. Tripoli ultimately received approximately 1.6 metric tons of the material. U.S. officials believe that North Korea was also a customer of the Khan network.

Malaysia's inspector general of police reported in 2004 that uranium hexafluoride was shipped from Pakistan to Libya in 2001. According to the IAEA, Tripoli received one shipment of the material in 2000 and another in 2001. The agency has not disclosed the material's origin.

Experts from the IAEA examined the material before it was shipped from Libya to the United States.

The Feb. 2 Times and Post reports quoted U.S. officials asserting that laboratory tests on both the uranium hexafluoride and its storage container indicate that the material originated in North Korea.

A Department of Energy official confirmed Feb. 22 that the evidence implicating Pyongyang included traces of plutonium on the storage container, as well as isotopic tests on the uranium. The plutonium reportedly matched samples taken from North Korea’s frozen reactor site.

However, in interviews with Arms Control Today, knowledgeable sources expressed skepticism that Pyongyang was Tripoli’s uranium supplier.

For instance, the Energy Department official stated that the reported evidence does not indicate that the material originated in North Korea, adding that there is a “certain leap of faith involved” in the assessment. The official did say, however, that the uranium hexafluoride is not from Pakistan.

A recent Department of State briefing for congressional staff did not dispel doubts about the intelligence, a source familiar with the issue added Feb. 24.

A diplomatic source in Vienna said Feb. 21 that the IAEA has “evidence” that North Korea was the supplier but has found “nothing conclusive” and is still investigating the matter. As for the reported U.S. findings, the source said IAEA experts did not find plutonium traces when they tested the container. IAEA experts judge the U.S. “methodology” to be neither “credible nor reliable,” another Vienna diplomat close to the agency said Feb. 19.

North Korea has indigenous supplies of natural uranium, but whether it can produce uranium hexafluoride is unclear. A former State Department official familiar with North Korea’s nuclear programs told Arms Control Today Feb. 22 that, as of October 2002, there was no evidence that North Korea possessed a facility for producing uranium hexafluoride. North Korea does have a facility for producing uranium tetrafluoride, a uranium compound that is then converted to uranium hexafluoride, that was frozen under the Agreed Framework, the official said.

However, Gary Samore, who headed nonproliferation efforts for the White House during the Clinton administration, said North Korea could “probably start making hex [uranium hexafluoride] fairly quickly,” Nuclear Fuel reported in September 2003.

The status of North Korea’s centrifuge facility efforts is also unclear. The CIA said in November 2002 that North Korea was “constructing a centrifuge facility” capable of producing enough fissile material for “two or more nuclear weapons per year” as soon as “mid-decade.” But subsequent reports have been increasingly vague. For example, a CIA report to Congress covering the last half of 2002 says only that North Korea “had begun acquiring material and equipment for a centrifuge facility” with the apparent “goal” of building a plant. Similar reports covering 2003 say nothing about the program.

A congressional source familiar with the program told Arms Control Today Feb. 7 that North Korea is apparently making little progress on its centrifuge program, although Pyongyang has probably acquired many of the necessary components for a centrifuge facility. Washington is focused on stopping Pyongyang’s acquisition of a list of certain critical items, the source said, adding that U.S. intelligence indicates Pyongyang probably lacks some of these items.