CNS Feature Story

Bushehr, Iran Satellite Photo [Src: Space Imaging]
Bushehr, Iran Satellite Photo [Src: Space Imaging]

Iranian Nuclear Program Remains Major Threat Despite Partial Freeze of Weapons-Relevant Activities Described in New U.S. National Intelligence Estimate

Despite a December 3, 2007 U.S. National Intelligence Estimate assessment that Iran's "nuclear weapons program" was halted in 2003, serious concerns remain.

Leonard S. Spector, CNS Deputy Director (Washington, DC)

December 6, 2007

On December 3, 2007, the U.S. National Intelligence Council released an unclassified summary of the newest National Intelligence Estimate (NIE) entitled "Iran: Nuclear Intentions and Capabilities." Although the assessment states that the US Intelligence Community has "high confidence" that Iran's "nuclear weapons program" was halted in 2003 and that the halt lasted for "at least several years," the document makes clear that the halt applied only to one facet of Iran's activities relevant to the development of nuclear arms. Moreover, other statements in the document, along with extensive evidence in the public domain, suggest that other activities relevant to the possible production of nuclear weapons continue. There are thus strong reasons for on-going concern about the future direction of Iran's nuclear activities. These concerns call for continued international pressure on Iran to curtail its work on uranium enrichment and plutonium production — technologies that can produce nuclear explosive material — and to permit more intensive inspections of its nuclear program to ensure it is not used to produce nuclear weapons.


Programs to develop nuclear weapons have a number of essential components. A state seeking such weapons must:

  • Design the weapon and all of its nuclear and non-nuclear component parts;
  • Produce the nuclear explosive material that forms the core of a nuclear weapon;
  • Manufacture the components and assemble the weapon;
  • Prepare a system for delivering the weapon, usually a specially equipped warplane or a missile.

Most programs also include provision for testing the weapon, although this is not considered a requirement for developing a first-generation nuclear device akin to those that destroyed Hiroshima and Nagasaki. Traditionally, these various efforts are conducted in parallel, and, as a rule, acquiring the necessary nuclear explosive material is considered the most difficult task.

Iran is developing a sizeable uranium enrichment facility at Natanz and the capabilities of this facility have steadily advanced. Currently 3,000 uranium enrichment centrifuges are operating at Natanz, although not consistently, according to the International Atomic Energy Agency (IAEA). The IAEA monitors the facility as required under the nuclear Nonproliferation Treaty (NPT) to which Iran is a party. Tehran claims it is building this plant to produce low-enriched uranium for nuclear power plant fuel, but the facility could also produce highly enriched uranium (HEU) suitable for nuclear weapons. The unclassified NIE summary states with "moderate confidence" that Iran "probably would be technically capable of producing enough HEU for a weapon sometime during the 2010-2015 time frame." Iran is also constructing a heavy-water moderated reactor at Arak, which is well suited for producing plutonium which can also be used as fissile material for a nuclear weapon. At the moment, it appears that the Iranian enrichment program is more advanced than the country's plutonium production program; the unclassified NIE summary does not speculate as to the completion date for the latter capability.


In mid-2002, an Iranian opposition group revealed that for the previous 18 years, Iran had pursued a clandestine program to enable it to produce nuclear weapon material, a program that had not been declared to the IAEA as required by the NPT. Subsequently, a series of facilities were linked to that effort and, under international pressure, Iran agreed to place them under IAEA monitoring, including the Natanz and Arak facilities. It was understood that prior to the construction of these units, Iran had pursued a range of related research and prototype development activities. In addition, through the IAEA inspection process and through revelations in early 2004 and afterwards regarding the nuclear smuggling network led by Pakistani nuclear scientist A. Q. Khan, it became known that Iran had received assistance from Khan beginning in 1985 on the development of a uranium enrichment capability, assistance that may have included a nuclear weapon design and which is known to have included instructions on machining HEU into hemispheres. The only known use for such hemispheres is in the core of nuclear weapons.

The clandestine effort started in 1985 is the baseline against which the NIE's statement concerning the 2003 halt in Iran's "nuclear weapons program" needs to be understood. The newest NIE states:

For the purposes of this Estimate, by 'nuclear weapons program' we mean Iran's nuclear weapon design and weaponization and covert uranium conversion and uranium enrichment-related work; we do not mean Iran's declared civil work related to uranium conversion [at Isfahan] and enrichment [at Natanz].[1]

Thus, the statement in the NIE that Iran halted its "nuclear weapon program" in 2003 means that of the four essential components of a nuclear weapon program, the Estimate states with high confidence only that nuclear weapon design/component preparation and clandestine, small-scale activities related to production of nuclear explosive material were halted in 2003. Moreover, the NIE qualifies the point by stating that these activities were halted "for at least several years" and that the intelligence community has only "moderate confidence" that the activities were not restarted as of mid-2007; both findings leave open the possibility that the "halt" may have been only a "pause," and that the activities in question may have restarted.

Far more disturbing, however, are the nuclear-weapon-relevant activities that Iran is known to have actively pursued since 2003:

  • Although Iran agreed under international pressure in November 2004 to suspend work on uranium enrichment, in August 2005, Mahmoud Ahmadinejad, Iran's newly elected hardline president, vowed to restart the program. Iran began converting uranium for use in the Natanz plant that month and restarted operations at Natanz in January 2006. Since then, it has been aggressively enlarging the Natanz facility, even in the face of international sanctions imposed under UN Security Council Resolutions 1737 and 1747.[2] Ahmadinejad, who has threatened to "wipe Israel off the face of the earth" and denies the Holocaust, claims the program is intended for the production of nuclear reactor fuel. Iran, however, has only one nuclear power plant—the Bushehr reactor—under construction and none on order. The reactor under construction is being built by Russia, which is under contract to supply all of the fuel for the lifetime of the facility. (The Arak reactor will use unenriched uranium). Thus, if the Natanz facility were intended for production of reactor fuel, its output would not be needed for at least a decade, raising questions as to why Ahmadinejad is rushing to complete it and exposing Iran to UN sanctions in the process.

  • Although Iran's nuclear-weapon design and weaponization work and clandestine enrichment and uranium conversion activities may have halted in 2003, the country has actively pursued other clandestine efforts to advance its nuclear and missile programs since that time, specifically the illicit acquisition of components and equipment via smuggling rings active in Austria, Germany, Great Britain, Turkey, and the United States, among other countries.[3]

  • Iran's development of missiles powerful enough to carry nuclear warheads considerable distances also continued during this period, in particular extending the range of the Shahab-3 to 1,300 kilometers. Tested most recently during a military exercise in November 2006, the system is based on the North Korean Nodong missile and is able to strike Israel. Historically, every state that has developed missiles of this range or greater has sought to arm them with nuclear warheads. Also in 2006, Iran is reported to have purchased a 3,000-kilometer-range system from North Korea, known as the Musudan, and to have tested the missile in January of that year.[4] Finally, Iran reportedly is preparing to test an indigenously produced solid-fueled ballistic missile, called Ashura, with a range of 2,000 to 2,500 km.[5]

In parallel with these activities, and in defiance of international demands, Ahmadinejad has curtailed IAEA access to Iranian nuclear sites. Beginning in 2003 — the same year Iran suspended work at Natanz and, according to the NIE, halted weaponization work — Iran had voluntarily granted the agency augmented inspection rights as specified in an amendment, known as the Additional Protocol, to its basic inspection agreement with the agency; Iran first signed the amendment in December 2003 and then implemented it even though the document was not yet ratified. Iran then granted the agency still further authority to interview Iranian scientists and review documents relevant to its nuclear program. Since his election, Ahmadinejad has systematically rescinded these privileges, slowly blinding the agency. Although the IAEA continues to implement its basic inspection rights, in his most recent report to the IAEA Board of Governors, the Agency's Director General Mohammed ElBaradei stated that, "...the Agency is not in a position to provide credible assurances about the absence of undeclared nuclear material and activities in Iran without full implementation of the Additional Protocol. This is especially important in the light of Iran's undeclared activities for almost two decades and the need to restore confidence in the exclusively peaceful nature of its nuclear program."[6]

Even if Iran has halted one facet of the work necessary for the production of nuclear weapons, it has vigorously pursued other activities essential to achieving this goal and has done so under the most suspicious circumstances — defying UN resolutions, exploiting international smuggling networks, developing missiles apparently designed for nuclear delivery, and restricting IAEA monitoring. All of these activities, moreover, accelerated after the advent of a new Iranian president with a radical international agenda. While Ahmadinejad may not have had final authority over Iran's nuclear policies, he has wielded considerable influence with those who did.


What comes next? Since Ahmadinejad took office, Iran has reversed key decisions of his predecessors to suspend uranium enrichment work at Natanz and to expand IAEA inspection rights. Will he also oppose continuing the halt on weaponization work? With the IAEA restricted and the United States, according to a senior Israeli official, having lost its crucial source of information on the weaponization effort, he may well believe these activities can be restarted without detection.[7]

The scenario of greatest concern at the moment is that once Iran is able to produce quantities of low-enriched uranium, it will build a stockpile of the material and, if it has not done so by this point, finish designing the bomb and building its non-nuclear components. It would then be in a position to withdraw from the NPT (as North Korea did in January 2003) and then upgrade its stocks of enriched uranium to weapons grade and fabricate complete nuclear weapons, steps that might be completed in a matter of months. With the NIE indicating that Iran could have the necessary weapons material sometime between 2010 and 2015, the threat of such a "break out" may not be a distant one.

The danger of a nuclear armed Iran thus remains very real indeed. The United States, its partners on the UN Security Council, and others, such as Germany and the EU, who have played leading roles in the attempt to constrain Iran's nuclear capabilities have every reason to sustain their efforts and must do so, in particular, by taking the next step in the process: imposing a third round of sanctions on Iran, while holding out the possibility of negotiations to ease the current impasse. Ahmadinejad's hardline cohorts face parliamentary elections early in 2008 and, as international economic sanctions have intensified, his intransigence on Iran's nuclear program has been the subject of growing domestic opposition. The international community needs to maintain pressure on Iran to change course and must not be deflected by taking greater comfort from the NIE than it actually provides.

[1] Uranium conversion is the process by which natural uranium oxide or "yellowcake" is converted into gaseous uranium hexafluoride, the material that is processed in uranium enrichment centrifuges.
[2] For a recent analysis of developments at the Natanz plant, see David Albright and Jacqueline Shire, "A Witches' Brew? Evaluating Iran's Uranium-Enrichment Progress," Arms Control Today, November 2007,
[3] See, e.g., "U.S. Nonproliferation Sanctions Against China and/or Chinese Entities," Nuclear Threat Initiative website,, noting repeated imposition of sanctions on Chinese firms since 2003 for transfers to Iran of items on international control lists; Ibrahim Al-Marashi and Nilsu Goren, "Iran Exploited Turkish Trading Firm to Produce Dual-Use Goods from Western European, U.S. Companies," WMD Insights, July/August 2006,; Adam P. Williams, "German And U.K. Investigations Target Nuclear Exports To Iran," WMD Insights, September 2007,
[4] Peter Crail, "Iran Missile Tests Heighten International Concerns," WMD Insights, December 2006/January 2007,; Daniel Pinkston, "North Korea Displays Ballistic Missiles During Military Parade, Some for First Time," WMD Insights, June 2007,
[5] Alon Ben-David, "Iran Adds Ashura to Missile Line-Up," Jane's Defense Weekly, December 5, 2007.
[6] Report by the Director General, "Implementation of the NPT Safeguards Agreement and Relevant Provisions of Security Council Resolutions 1737 (2006) and 1747 (2007) in the Islamic Republic of Iran," GOV/2007/58, November 15, 2007,
[7] Steven Erlanger and Isabel Kershner, "Israel Insists That Iran Still Seeks a Bomb," December 5, 2007,

View previous Feature Stories.

Author(s): Leonard S. Spector
Related Resources: Iran, Nuclear, Middle East, Feature Story
Date Created: December 6, 2007
Date Updated: December 17, 2007
Return to Top