In This Issue
Nuclear Dangers
June 15, 2010 Volume 40 Issue 2

Iran's Nuclear Program: Status, Risks, and Consequences

Friday, June 11, 2010

Author: Brian Radzinsky and George Perkovich

In the long run, a non-peaceful nuclear program will neither sustain nor secure the Iranian people.

Whether or not Iran actually builds nuclear weapons, its nuclear activities pose an acute challenge to international order. By defying International Atomic Energy Agency (IAEA) demands and UN Security Council (UNSC) resolutions to cease its suspect activities and build international confidence in the peaceful nature of its nuclear program, Iran continues to mock the rule-based system for preventing nuclear proliferation. If the Islamic Republic goes further and weaponizes the nuclear capabilities it is accruing, the risks of war in the Middle East will increase as Iran and its neighbors adjust to the shifts in power.

The stakes are high, and nothing the United States, UNSC, or Israel could do has a high probability of resolving the situation happily. In the long term, a non-peaceful nuclear program will neither sustain nor secure the Iranian people, which can only exacerbate the structural weaknesses of the Iranian government. Increasing isolation from international investment and other cooperation will further weaken Iran, although it may not keep the country from building nuclear weapons.

Since the revelation in late 2002 that Iran was building facilities and acquiring other capabilities that could enable it to produce fuel for nuclear weapons, the United States, and later the UNSC, have demanded that Iran cease work related to the nuclear fuel cycle. Meanwhile, the collective Iranian leadership, headed by Supreme Guide Ayatollah Khamenei, has declared its bottom line from which it will not depart—Iran will not foreswear uranium enrichment formally or for any length of time that would seriously impede the technical development of this capability (Figure 1).

Figure 1

Tehran continues to reject the premise at the heart of the international community’s bargaining position—that Iran’s long history of noncompliance with safeguards requirements and the suspect nature of some of its activities require a suspension of further fuel-cycle development to build international confidence that Iran’s nuclear intentions and actions are purely peaceful.

The Obama administration came into office hoping that engagement and negotiation would break the impasse with Iran. The revelation in late September 2009 that Iran was secretly building another enrichment facility once again put Iran on the defensive.

In October, Iran and the P5+1 (Britain, France, Germany [the EU-3], China, Russia, and the United States) met in Geneva for the first talks since Obama took office. The talks seemed to result in a deal to ship Iran’s stockpile of low-enriched uranium (LEU) to Russia or France in return for fuel for the Tehran Research Reactor (TRR), which is used to produce medical isotopes. The deal was designed to build trust on both sides.

Iran’s LEU stockpile contains enough uranium-235 to fuel at least one nuclear weapon if it were enriched further. Transferring this material to a third country would have pushed back the time when Iran could be expected to produce a nuclear weapon.  Meanwhile, by following through with the deal to provide Iran with reactor fuel, the United States, France, Russia, and other counterparts could reinforce Iran’s confidence that bargains would be kept.

Although Iran did not reject the deal outright, it proposed several modifications that the P5+1 have thus far dismissed as non-starters. After President Ahmadinejad’s opponents in Tehran’s ruling circles accused him of being willing to give away too much, he became wary of being tricked or of losing leverage. He then proposed sending only a fraction of Iran’s stockpile out for enrichment and receiving fuel for the TRR at the same time.

Only a few facilities can produce the specific fuel required for the TRR, which takes at least several months to manufacture. Even though Iran’s interlocutors were eager to remove uranium that had already been enriched (as it continues to enrich more), Tehran insisted on simultaneity.

The Obama administration reluctantly concluded in early 2010 that Iran’s leadership is unwilling or unable to negotiate seriously on mutual confidence-building steps to calm and ultimately resolve the nuclear confrontation. Therefore, the United States, France, and the United Kingdom are pushing the UNSC to adopt another round of sanctions.

Although most officials admit privately that they do not believe sanctions will cause Iran to suspend enrichment and cooperate fully with the IAEA, they hope that strengthening sanctions will motivate Iran to negotiate seriously with the P5+1. If Iran were to agree that it must take serious steps to build international confidence in its intentions, the P5+1 privately appear ready to tolerate some level of ongoing uranium enrichment. Paris, London, and Washington would do so with great reluctance, but other Security Council members are inclined to concede this fundamental point.

The absence of viable military options for solving the problem is a major reason for the grudging (albeit private) recognition that Iran would be “allowed” to continue enrichment if it engaged in serious give-and-take. John McCain, Sarah Palin, and numerous others contend that it only requires the political will and bombing to end the Iranian nuclear challenge. In a Senate Armed Services Committee hearing on April 14, McCain said the U.S. “keeps pointing the gun, we haven’t pulled a single trigger yet, and it’s about time that we did.”1 However, U.S. defense officials who have studied military options for years conclude that “military options are not preferable.”2

It is true that missiles and bombs could destroy most of the known targets (although it would take weeks of attacks according to most experts) (Albright et al., 2008). If the nuclear threat were only from known, targetable facilities, running the risks of war might not be imprudent. However, if attacks did not destroy enough capabilities to forestall progress toward nuclear weapons long enough (probably a number of years) for the political system to produce a friendly new government, war with Iran would make little sense. After being attacked, the current regime would almost certainly be more hostile, would kick out international inspectors, and would rush to build nuclear weapons.

American (or Israeli) bombing would also probably inspire sympathetic Muslim populations and political-terror organizations to support Iran politically and perhaps in other ways. Iran’s Revolutionary Guard and other agencies would use proxies to escalate attacks on American interests and personnel in Iraq and Afghanistan.

Defense Secretary Robert Gates and Joint Chiefs Chairman Admiral Michael Mullen have downplayed the utility of military action and acknowledged that Iranian counteractions could gravely harm U.S. interests in Iraq, Afghanistan, and elsewhere. In February, Mullen voiced concern “about the unintended consequences of any sort of military action” and warned that “no strike, however effective, will be in and of itself decisive” (Agence France-Presse, 2010). More recently, the vice chairman of the Joint Chiefs of Staff, General Cartwright, told a Senate committee that “military activity alone is not likely to be decisive,” and a war would affect U.S. military readiness and the economy.3

With no promising options, there is a natural tendency to bide time. Through diplomatic pressure, sanctions, covert action to disrupt the procurement and operation of nuclear equipment, and the mobilization of states in the region and conventional forces to contain Iran, the United States and its allies are attempting to delay Iran’s ability to make nuclear weapons and deter its leaders from deciding to do so.

How much time is there is to “bide”? Would one weapon pose an operational threat, or would Iran need several weapons before it could take threatening action against Israel and the interests of the United States and Iran’s neighbors with confidence that it could deter retaliation? Would the international community have adequate warning? How would other states react?

Pathways to Proliferation

Iran can go down one of two pathways to a nuclear weapon. It can either divert declared nuclear material from safeguarded facilities and rush to produce one or more weapons with it, or it can build one or more clandestine enrichment plants. Either approach entails political risks and technical challenges.

Diversion of Nuclear Material

IAEA inspectors would most likely detect the diversion of nuclear material in time for the international community to muster a response. There is only a slight chance that Iran could bamboozle inspectors either by delaying their entry into facilities or by transferring nuclear material out during the window between inspections. If inspectors found that material had been diverted, the IAEA Board of Governors would be required to find Iran in noncompliance with its safeguards agreement and report the matter to the UNSC. Similar steps were taken (slowly) in 2005 and 2006 in response to Iran’s violations through late 2002.

Presented with evidence of diversion, the United States and others could seek tougher measures in the Security Council, including authorization to use military force. Alternatively, the United States or Israel could decide that Iran’s actions posed an imminent threat that warranted a pre-emptive military attack. Iran has to weigh the likelihood and consequences of detection against the expected benefits of overtly pursuing a nuclear weapon.

Construction of Clandestine Enrichment Plants

Iran is more likely to produce fuel for a nuclear weapon at one or more clandestine enrichment facilities than to divert nuclear materials. The country has undertaken dozens of tunneling projects with ostensibly non-nuclear applications to mask its activities from foreign intelligence agencies (Broad, 2010). At the same time, the IAEA’s authority to inspect suspicious activity has been limited because Iran has refused to implement an Additional Protocol to its safeguards agreement.

Other secret facilities would be necessary to sustain a secret enrichment program. At a minimum, a clandestine program would require a parallel plant to convert uranium ore into a form suitable for enrichment. At the moment, Iran’s only operating conversion plant is under safeguards and would be easy to destroy. Iran would probably not risk diversion from that plant under the IAEA’s gaze.

Non-nuclear Components

While acquiring highly enriched uranium (HEU) and/or plutonium is the most important and difficult step in making nuclear weapons, the design, manufacture, and assembly of the non-nuclear components for a missile-deliverable weapon is more difficult than most people think. General Cartwright, the former head of the military command in charge of U.S. nuclear weapons, said recently that Iran could probably not assemble a nuclear explosive or a missile capable of delivering it for three to five years.4 (Building a gun-type uranium-fueled nuclear bomb that could be transported by ship, truck, or large plane is much easier but is also more likely to be interdicted. Such a weapon would most likely be used against a large target whose destruction would be likely to invite massive retaliation against Iran).

Iran may already have the design of a nuclear weapon and may already have secretly manufactured and tested non-nuclear triggering mechanisms. If these capabilities and activities were not kept secret, the United States, Israel, and others would have a “smoking gun” to prove that Iran seeks nuclear weapons and is a clear and present threat to international peace and security. Iran must also keep secret any work still necessary to be able to manufacture a reliable nuclear weapon; the measures necessary to ensure secrecy would also add to the risk and time required for Iran to become a nuclear-armed state.

Building a Nuclear Arsenal

Another major variable for Iran (and the world) is whether decision makers in Tehran would insist on stockpiling enough HEU for multiple weapons, and if so, how many. One nuclear bomb would make it impossible for Iran to conduct a nuclear test explosion without consuming its deterrent at the same time. However, testing would demonstrate to Iranian leaders, the population, and neighbors that Iran had become a nuclear power.

Of course, testing would also invite international consequences that Tehran wishes to avoid. Without testing (or close consultations with friendly foreign nuclear-weapon experts), Iranian leaders might not be fully confident that they actually were in control of a workable nuclear weapon.

Even if Tehran chose not to conduct tests, it would probably try to produce several nuclear weapons without being detected. The more weapons, the greater the confidence that the United States, Israel, or other adversaries would not be able to destroy Iran’s new deterrent before it was “launched,” and the more difficult to would be to intercept Iranian weapons on the way to their targets.

Depending on how many weapons Iran wants before it acts in more assertive ways that would threaten Israel, the United States, and others, Iranian leaders are not likely to behave more belligerently until they have acquired this quantum. This, too, could mean that the United States and others have more time to prevent, dissuade, or deter Iran from posing such a threat. The question is how long it would take to produce the fuel for the desired number of weapons.

How Long Until Breakout?

Because the imperative of policy and politics is to keep Iran from acquiring the capability to produce even one nuclear weapon, breakout scenarios tend to focus on this minimum threshold. Thus the question is how long it would take Iran to produce 20 to 30 kilograms of 90 percent enriched uranium. Worst-case estimates are that Iran already has the know-how, equipment, and components to make a weapon as soon as it has enough fissile material. In that case, the production of fissile material becomes the key indicator.

Estimates vary for how long it would take Iran to produce enough HEU. Recently, the director of the Defense Intelligence Agency told a Senate committee that Iran could produce enough HEU for one nuclear weapon within a year.5 Some experts estimate that Iran could break out with a nuclear weapon in less than two months. Others think Iran would need at least a year of uninterrupted time.

At the lower bound, Gregory Jones of the Nonproliferation Education Center estimates that if Iran recycled its LEU stockpile through a reconfigured centrifuge cascade of 3,000 machines, it could produce enough fuel for a nuclear weapon in 43 days (Jones, 2010). The number drops to 22 days if Iran uses 6,000 machines. Other experts, such as Albright, Brannan, and Shire (2008), however, calculate that with 3,000 centrifuges and Iran’s existing stockpile of LEU, weapons-usable uranium could be produced in two to five months (Albright et al., 2008). At the upper bound, Kemp and Glaser (2009) estimate that, under various scenarios, Iran could produce weapons fuel in one to three years.

The Centrifuge Program

In the near term, the primary impediments to Iran’s nuclear-weapons capability are the small size of its uranium stockpile and the quality and quantity of its centrifuges. Several factors will affect when Iran might produce a sufficient quantity of weapons-usable uranium: the average efficiency of Iran’s centrifuges; the amount of stockpiled nuclear material; the centrifuge production and installation rate; the number of centrifuges running at any given time; centrifuge reliability; and Iran’s willingness to trade off a higher rate of centrifuge malfunction for a higher enrichment rate.

Estimates of breakout time fall along three main axes: (1) separative capacity; (2) the number of centrifuges used; and (3) whether Iran will “batch recycle” LEU to produce weapons fuel. We consider each of these in turn, and then discuss their advantages for Iran.

Separative Capacity

Centrifuges separate fissile uranium by rotating at high velocities. Because an individual centrifuge can only separate a small quantity of fissile material, it takes large cascades of interconnected machines to produce significant quantities of nuclear fuel. One reason for the differences in estimates is that experts disagree about the efficiency, or separative capacity, of Iran’s centrifuges. Because the number of centrifuges being used for enrichment is not known, experts have had to make rough calculations of separative power based on the total number of centrifuges and the amount of material produced thus far, as measured by the IAEA.

Separative capacity affects the economic viability of the enrichment program as well as the timeframe for producing a nuclear weapon. The separative power of Iran’s centrifuges, measured in separative work units (SWUs) per year, provides a basis for making rough calculations about how much nuclear material Iran could produce in a given time for various centrifuge configurations. Thus, doubling the SWU/year of a centrifuge roughly doubles the amount of material it can enrich in a given timeframe.

Technical problems are likely to frustrate Iran’s plans to attain higher enrichment levels. Centrifuges are delicate machines, and minor flaws in construction, assembly, or calibration can cause them to break down. Iranian scientists have made steady progress, but they continue to face a number of problems that might force cutbacks in enrichment. Rumors abound of clandestine foreign-instigated sabotage of Iran’s machines, which rely on imported components.

Number of Centrifuges

Recent reports indicate that Iran is feeding roughly 4,000 centrifuges with nuclear material; another 3,000 have been installed but are not yet enriching nuclear material. However, because of technical problems, only a fraction of the 4,000 to 7,000 machines may be enriching uranium at any given time.

Because Iran has not implemented the Additional Protocol, IAEA inspectors are not allowed into the centrifuge manufacturing facilities. Therefore, we do not know the rate at which Iran is assembling new centrifuges or whether Iran has begun to manufacture more advanced models in significant numbers. Experts assume that the workhorse of Iran’s program for the foreseeable future will remain the IR-1 centrifuge, but in a recent announcement Iran boasted that a third-generation centrifuge had been completed. Whether this new centrifuge will be produced in large numbers and will meet high expectations is not clear as of this writing (Global Security Newswire, 2010).

Batch Recycling

The plants that Iran has acknowledged enrich natural uranium into LEU under 5 percent. However, the cascades could be reconfigured to “batch recycle” fuel multiple times until it attains a sufficiently high enrichment level. This would significantly reduce the time it takes to produce weapons-usable fuel, because gains in enrichment grade are not linear. As higher enrichment levels are fed through the cascades, the amount of time it takes to attain even higher concentrations decreases (given a certain separative capacity).6

The Plutonium Pathway

So far, Iran’s program has focused almost exclu-sively on producing enriched uranium. However, in the future, Iran might develop plutonium production capabilities as well. Iran’s experience with plutonium has been limited to producing small quantities in the laboratory. However, the country is constructing a heavy water reactor in Arak capable of producing enough plutonium for about two bombs per year.7 Because Iran has not fully cooperated with IAEA requests to inspect the facility, ongoing work at Arak is cause for concern.

If Iran were to produce plutonium indigenously, it would also have to build specialized facilities known as “hot cells” to extract plutonium from the spent fuel. In 2004, Iran announced that it was scrapping plans to build hot cells capable of reprocessing plutonium because of difficulties procuring the necessary equipment (IAEA, 2004). If Iran eventually chose to build plutonium-friendly hot cells at Arak, it would have to submit updated design information to the IAEA.


If Iran decided to build nuclear weapons and was interrupted in the process by a military attack, it is extremely difficult to predict the consequences. Much would depend on the ensuing actions and reactions. We do know that there would be serious consequences in Iran itself, in the broader Middle East, and in the overall international system.

It is slightly less difficult to predict what would happen if the Islamic Republic of Iran succeeded in acquiring a small nuclear arsenal. The primary threat would then be that the government of Iran, including the agencies that support subversive or terrorist organizations outside Iran, would be emboldened to challenge the interests of Israel, moderate Arab states, and the United States.

For example, groups such as Hezbollah, Islamic Jihad, Hamas, and the states or other actors that support them could be provided with more potent means of violence and subversion and encouraged to pursue causes they share with Iran’s ascendant Revolutionary Guard. These actors and Iran could believe that Iran’s nuclear capability would deter Israel and the United States from pursuing counterforce tactics against them.

Fearful, smaller Arab states in the Persian Gulf, as well as Egypt, might try to accommodate Iran in hopes of inducing it to refrain from actively threatening their interests. In return, Iran could demand that these states distance themselves from the United States and pursue more radical policies toward Israel. The United States would try to counter Iranian gains by intensifying military aid and other assistance to induce Iran’s neighbors to work more closely with the United States to contain Iran’s projection of power.

The risks of acute crises and military conflicts would increase as Iran tried to project power and influence while being countered by the United States, Israel, and others. The ominous shadow of Iranian and Israeli nuclear weapons would hang over the political-security environment, resulting in the daunting prospect of managing crises that could go nuclear without significant warning.

The ongoing need for the United States to project power in the Persian Gulf (including Iraq) and Afghanistan would be significantly complicated by Iran’s potential to use nuclear weapons against U.S. forces and the countries that host them. In short, the region—from the Levant through the Persian Gulf and Afghanistan—would become even more volatile than it is now.

By rough analogy, India and Pakistan have engaged in one armed conflict and two military crises in the 12 years since they conducted nuclear tests. However, unlike Iran, both India and Pakistan maintain relatively good relations with the United States, which has enabled Washington to intervene diplomatically to help end the Kargil conflict in 1999 and the 2001–2002 and 2008 post-Mumbai crises. But the strategic relationship between India and Pakistan has still not been stabilized.

Thus, it is clear why the United States and other governments that seek to preserve and enforce 21st century norms of international security, economics, and human rights are so alarmed by Iran’s apparent unwillingness to negotiate an equitable resolution of the crisis it initiated by violating the rules regulating the peaceful use of atomic energy. Diplomatic options for resolving the crisis are dwindling, and military alternatives are fraught with dangerous consequences. It’s no wonder that biding time looks like the least-bad policy.


Agence France-Presse. 2010. Any strike against Iran would not be ‘decisive’: US military chief. February 21, 2010. Available online at

Albright, D., P. Brannan, and J. Shire. 2008. Can military strikes destroy Iran’s gas centrifuge program? Probably not. ISIS Report, August 7, 2008. Available online at

Broad, W.J. 2010. Iran Shielding its Nuclear Efforts in Maze of Tunnels. New York Times, January 5, 2010.

Global Security Newswire. 2010. Iran Unveils New Enrichment Centrifuge. April 9, 2010. Available online at

IAEA. 2004. Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran: Report by the Director General. June 1, 2004. Available online at

IAEA. 2010. Implementation of the NPT Safeguards Agreement and Relevant Provisions of Security Council Resolutions 1737 (2006), 1747 (2007), 1803 (2008) and 1835 (2008) in the Islamic Republic of Iran: Report by the Director General. February 10, 2010. Available online at

Jones, G. 2010. Iran’s Increasing Progress towards a Nuclear Weapons Capability: Centrifuge Enrichment and the IAEA February 18, 2010 Update. February 23, 2010. Washington, D.C.: Nonproliferation Policy Education Center. Available online at

Kemp, S., and A. Glaser. 2009. Statement on Iran’s ability to make a nuclear weapon and the significance of the 19 February 2009 IAEA report on Iran’s uranium-enrichment program.  March 2, 2009. Program on Science and Global Security, Princeton University, Princeton, N.J. Available online at


 1 In an interview with Fox News in February, Palin said she would like Obama to declare war on Iran, or “decide[d] to really come out and do whatever he could to support Israel.” She suggested that such actions would improve U.S. security while helping Obama’s chances for reelection. “TRANSCRIPT: Fox News Sunday Interview With Sarah Palin,” February 7, 2010,

 2 James Cartwright and Michelle Flournoy, “Prepared Joint Statement Before the Senate Armed Services Committee,” April 14, 2010.

3 James Cartwright, “U.S. Policy Towards the Islamic Republic of Iran,” hearing of the Senate Armed Services Committee, April 14, 2010. Text from Federal News Service. Accessed April 19, 2010.

4 James Cartwright, “U.S. Policy Towards the Islamic Republic of Iran,” hearing of the Senate Armed Services Committee, April 14, 2010. Text from Federal News Service. Accessed April 19, 2010.

5 Ronald Burgess, “U.S. Policy Towards the Islamic Republic of Iran,” hearing of the Senate Armed Services Committee, April 14, 2010. Text from Federal News Service. Accessed April 19, 2010.

6 Iran has recently taken steps toward a batch recycling capability. On February 9, Iran informed the IAEA that it would be feeding the centrifuges at its pilot enrichment plant with a small quantity of LEU to produce 20 percent enriched uranium fuel for the Tehran Research Reactor, even though Iran lacks the capacity to manufacture such materials into fuel assemblies, and international offers have been made to supply the fuel (IAEA, 2010).

7 According to ISIS (see

About the Author:Brian Radzinsky is junior fellow and George Perkovich is vice president for studies, Carnegie Endowment for International Peace.