February 1, 2008  

Iran and the nuclear nightmare

Is Iran covertly developing atomic weapons in defiance of international constraints, and is it playing fast and loose with the facts as it rationalizes its nuclear activities? The Dec. 3 National Intelligence Estimate (NIE) states with high confidence that Iran shut down its nuclear weapons program in 2003. However, the NIE refers only to bomb design and not to the long poles in the weapons tent, plutonium and enriched-uranium production, both of which appear to have been continued by Iran.

The NIE then goes on to assert that Iran is pursuing “civilian” nuclear activities and that its strategy is based on “cost-benefit” analysis. Both assertions are challenged in this essay.

The International Atomic Energy Agency (IAEA) has attempted to monitor and constrain Iran’s concealed nuclear program for several decades with only marginal success. Iran’s subterfuge has been difficult because the physics, engineering and economics of nuclear power are too well established and the international community has become highly skeptical of Iran’s peaceful intentions. There are three independent programs that have caused concern: concentration of natural uranium in gas centrifuges to produce weapons-grade levels; refining and separating plutonium from reactor waste materials; and breeding plutonium from the most common constituent of natural uranium, U-238. Iran has a heavy-water development program that can play a significant role in plutonium breeding. Admittedly, heavy water has a civilian use in that it permits direct use of natural uranium as fuel (obviating expensive U-235 purification to reactor grade). However, it also allows the breeding of plutonium for highly efficient nuclear weapons.

Iran denies it has a weapons program and maintains that its nuclear activities are for commercial power. Yet Iran redundantly pursues both a heavy water program and a gas centrifuge uranium-enrichment program. It has further publicly declared that its heavy water program is additionally intended to provide a cure for AIDS and cancer. That medical rationale has just a slight grain of truth in it sufficient to preclude dismissal out of hand. However, it is far from convincing and must be viewed with great suspicion.

If Iran is indeed pursuing nuclear weapons, how close is it and can it be stopped? Best estimates indicate Iran is several years away from building a bomb but that stopping it will be difficult. A course of action featuring diplomacy, sanctions, incentives and a public demonstration of military capabilities for destroying Iran’s weapons potential is recommended. Hopefully, this combination will deter Iran from restarting its bomb design program and stockpiling weapons. What if it doesn’t? Aside from the possibility that Iran might attack Israel with nuclear weapons, the range of consequences varies from the bad to the catastrophic. Iran could simply be establishing a position of military and political dominance in the Middle East. Unfortunately, this “optimistic” scenario would undoubtedly initiate a nuclear arms race in the region with Saudi Arabia, Egypt, Syria and Turkey, among others, striving to attain parity or superiority. Iran might also become a nuclear weapon supplier for global terrorists intent on punishing the West. Both are untenable for the security of the U.S., Europe and the Middle East. Somehow, Iran must be deterred or stopped (the NIE notwithstanding).

Iran’s nuclear activities date to 1959, when the shah ordered the establishment of a research center at Tehran University. Support was obtained from the U.S., Europe, Russia, China, India and Pakistan, both before and after the radical Iranian Revolution in 1979. In 2003, important nuclear facilities were still operating at Tehran University, including a 5 megawatt research reactor. Dozens of additional nuclear activities are spread throughout the country. The most important confirmed nuclear sites are: å Bushehr: 1,000 megawatt light water reactor.

å Arak: heavy water separation plant and 40 megawatt reactor.

å Isfahan: uranium-hexafluoride conversion plant for providing centrifuge feed.

å Natanz: gaseous uranium centrifuge complex.

å Saghand and Gachin: uranium mine and extraction complexes.

The heavy water complex at Arak and the uranium-enrichment centrifuge facility at Natanz are prime examples of Iranian duplicity. If Iran’s nuclear ambitions are solely for powering electrical generators, these two facilities constitute an expensive redundancy defying the logic of both physics and economics. The economics and enabling resources for the Bushehr complex of light water reactors are also challengeable and damning.


Heavy water is deuterium oxide with the chemical formula D2O. Deuterium is the hydrogen isotope containing one proton and one neutron, as opposed to the much more abundant one proton configuration. Some significant properties of heavy water and regular light water are compared in the accompanying chart.

Heavy water occurs naturally mixed with regular water at a concentration of about 0.015 percent. The simplest way to separate it is by vacuum distillation, a process that is, however, extraordinarily expensive.

Heavy water separation costs can be considerably reduced, however, using chemical extraction techniques. The most widely used is the bi-thermal Girdler-sulfide process, which employs gaseous hydrogen sulfide as the extractor. Heavy water is produced in that way by Canada, India, Argentina, Norway and others. The Canadians also have recently perfected a new, more efficient process called combined electrolysis and catalytic exchange.

If the Iranians want heavy water for medical purposes, they can satisfy their needs by importing 500 kilograms annually at a cost of $150,000 plus operating expenses for a “hot cell.” However, the heavy water reactor at Arak, with a rated capacity of 40 megawatts, requires an initial heavy water charge of 80 to 90 tons and annual replacement of 1 ton. Iran has announced that its heavy water production capacity will be 8 tons annually with expansion capacity to twice that level. At current prices, that would come to D2O valued at $4.8 million, more than 30 times the requirement for medical use. There is clearly a disconnect, logically and cost-wise. The facility to manufacture heavy water is itself estimated to cost many tens of millions of dollars. It seems clear that Iran wants heavy water for far more than medical purposes.

A previously secret gas centrifuge uranium-enrichment facility at Natanz was divulged by an Iranian opposition group in August 2002 and confirmed by satellite imagery. Iran possesses only modest natural uranium resources, but has nevertheless been developing a uranium hexafluoride facility to provide feed material for the Natanz plant. Iran has not permitted the IAEA to inspect Natanz adequately and has not been forthcoming regarding the purpose of the complex.

Iran has acknowledged two significant uranium mines, one at Saghand and the other at Gachin. The Gachin mine was undeclared prior to May 2004, but it has since been imaged by satellite. The Saghand site, first reported in 1985, is of modest capacity: 1,000 tons of uranium ore. The Gachin site alone is estimated to produce 21 metric tons per year, sufficient for four nuclear bombs. Iran therefore has ore resources for many bombs, but as will be shown, only a few years’ supply for commercial electricity generation.

The feed material for a uranium gas centrifuge is uranium hexafluoride (UF6). A number of difficult steps are required to produce UF6, starting with ore from the mine. An intermediate product, solid uranium oxide (U3O8), known as yellow cake, is first produced. Facilities for producing yellow cake exist at both Saghand and Gachin. The final step for converting yellow cake to UF6 involves a reaction with highly hazardous hydrogen fluoride. A UF6 conversion plant exists at Isfahan.

The uranium in yellow cake is 99.3 percent nonfissile U-238 and only 0.7 percent U-235. The isotope mixture must be refined to a higher concentration of U-235 to be useful in anything other than a heavy water reactor. The Natanz facility is for U-235 enrichment.

The estimated size objective of the gas centrifuge facility at Natanz has an upper limit of 50,000 centrifuges. To provide perspective, a 1,300-stage facility being built in Ohio by USEC Corp. is designed for enrichment to the 10 percent level and costs about $1.7 billion. The Natanz facility, if carried through to completion, would be capable of very high enrichments, greater than 90 percent, suitable for weapons, and the costs could be in the neighborhood of $10 billion.

In 2003, the IAEA determined that a cascade of 164 centrifuges had already been installed at Natanz and, according to news reports, by mid-2007 15 such cascades had been largely completed. Edward N. Luttwak, in his report “Three Reasons Not to Bomb Iran — Yet,” estimated that a minimum of 1,000 centrifuges working around the clock for a year is required to produce enough uranium for a single primitive bomb. Clearly Iran’s progress has been slow, and it does not now have a robust capability. However, progress could increase dramatically once Iran is high enough on the learning curve. More important, when and if scientists and technicians who support the radical movement master advanced centrifuge skills, it will be difficult, if not impossible, to foreclose future weapons-grade uranium refinement on their part.


Perhaps the most blatant disconnect in the Iranian program is the simultaneous pursuit of heavy water manufacture and gas centrifuge uranium enrichment. Heavy water is extensively used as a moderator in nuclear reactors, i.e., as a coolant that also slows most fast neutrons to thermal status, permitting highly efficient fission processes to occur. As earlier stated, this allows the use of natural uranium as fuel instead of lightly enriched uranium (0.7 percent instead of 4.7 percent). If the objective is to produce only electricity, natural uranium is the way to go. It requires heavy water production at an estimated cost of $27 million as coolant for the 40 megawatt reactor; if the intent is ultimately to generate 7,000 megawatts of electricity, the cost is about $4.7 billion. Compare this to the $10 billion required to refine lightly enriched uranium using gas centrifuges. It is far more likely that the heavy water will be used to generate a sufficient flux of neutrons to allow fertilization of U-238 into plutonium in its 40 megawatt reactor. Enough plutonium for three or four bombs annually can be bred in this way. Note that if the 40 megawatt reactor’s purpose is to produce electricity, it would contribute only a miniscule amount to Iran’s announced objective of 7,000 megawatts.

Iran does not possess confirmed natural uranium resources sufficient to generate 7,000 megawatts of electricity in light water reactors. Its confirmed uranium ore reserves are only 1,400 tons. (The Iranians have speculated they have in excess of 5,000 tons.) The 1,000 megawatt Bushehr reactor consumes about 20 tons of lightly enriched (4.7 percent) uranium annually. Since the normal lifetime of a pressurized water reactor is about 30 years, Iran can support at best one reactor, not seven. Using confirmed reserves, they cannot support even one reactor for more than 10.4 years. Admittedly, they may discover more uranium, but a better strategy to supply seven Bushehr-type reactors is to import yellow cake rather than depend on discovering new reserves. Another tenable strategy is to convert the Bushehr complex to use heavy water. That would permit Iran to use natural uranium rather then lightly enriched uranium and run seven reactors for more than 30 years.

Iran would get a much better return with less risk by focusing on hydrocarbon fuels rather than the pricey, speculative, trouble-plagued uranium enrichment facility at Natanz. If they have indeed done a cost-benefit analysis, they have apparently reached the wrong answer.

With these economic negatives related to electricity production, it would appear that Iran is separating uranium isotopes at Natanz for other than civilian purposes, such as enrichment of U-235 to weapons purity (i.e., greater than 90 percent). Extrapolating Luttwak’s calculations9, 3,000 to 4000 centrifuges would be required to provide a robust capability to enable a few bombs per year, and 50,000 centrifuges would be enough to make Iran a nuclear power.

Iranian officials have announced on several occasions that their heavy water program is partially intended to facilitate the discovery of cures for AIDS and cancer. They specifically refer to the beneficial use of water that is depleted of D2O. The claim is that “deuterium-depleted water disrupts the reception of cancer cells and AIDS viruses,” which are gradually expelled from the body. Unfortunately, no confirmation of these effects can be found in any responsible literature. The announcement may be good propaganda, but the science smacks of quackery.

Radioactive isotopes are indeed used to treat cancerous tumors, and some research indicates that extreme doses of heavy water facilitate the penetration of neutrons into cancerous tissue. However, as previously observed, Iran has not undertaken design, certification and construction of the required “hot cells” necessary for production and handling of isotopes in Arak’s 40 megawatt reactor.

Iran’s rationale for its nuclear activities therefore fails the smell test on a number of counts. Its explanations fall short on economic grounds, from the points of view of physics and available natural resources, and from the standpoint of medical research. It is difficult to support the conclusion that Iran’s activities are civilian in nature, as implied by the NIE. It is reasonable to conclude that Iran is indeed attempting to develop nuclear weapons, an unpleasant and unsettling situation.

If Iran successfully develops and tests nuclear weapons, the consequences would be profound. At a minimum, the strategic balance of power in the Middle East would be overturned and a nuclear arms race in the region initiated. Egypt, Saudi Arabia, Turkey and possibly Syria would then strive for nuclear parity or superiority. If the cork is not now out of the bottle, it would be then.

Iran might also become a nuclear arms supplier to global terrorists. Hamas in the Gaza Strip, Hezbollah in Lebanon, al-Qaida in Iraq and possibly terrorist cells in the U.S. and Europe could become nuclear threats. The unacceptability of these developments speaks for itself.

Finally, Iran might directly threaten Israel with nuclear attack even though a nuclear exchange would be highly unfavorable to Iran. (Israel is thought to possess about 100 nuclear weapons that could devastate the densely populated areas of Iran.) It is also possible that Israel might be provoked to strike Iran pre-emptively with conventional non-nuclear weapons. Such an action might threaten worldwide stability.

Any of the foregoing would be highly unfavorable for world peace and potentially catastrophic. On the other hand, precipitous action to stop Iran might also have negative consequences. Military action against Iran’s nuclear facilities could very well energize the Iranian people to rally around and strengthen what is currently an unstable regime. Military action, especially if only partially successful, might weaken whatever support the U.S. has in the U.N. and Europe to contain Iran’s ambitions. The issue of whether to constrain Iran militarily, and particularly the timing thereof, is by no means a closed case. The recent NIE on Iran’s nuclear activities further muddies the waters.


There are three positions that can be taken in answer to the question of whether Iran should be stopped militarily: 1. Iran should be stopped and soon.

Nuclear weapons in the hands of the Iranian radicals would be a disaster for world peace and highly detrimental to the security of the Middle East, Europe and the U.S. Since economic and political deterrence has not been effective, Iran should be stopped militarily. Early military action is preferable to later attack, because the Iranians are building up air defenses and hardening their nuclear sites. Early action by the U.S. would make an independent pre-emptive attack by Israel unnecessary. In the absence of a confirmed stop to Iran’s nuclear program, an eventual attack by Israel is highly likely.

2. Iran should be stopped, but not now.

The case for eventually stopping Iran militarily is persuasive, but there is no hurry. Iran’s radical regime is unstable and may collapse of its own accord. Moreover, Iran is two to four years away from accumulating enough uranium or plutonium for weapons and probably five to 10 years away from having nuclear devices in inventory. In the interim, the U.S. should intensify efforts to deter Iran’s nuclear weapons program politically, through the use of economic sanctions and possibly through the offer of incentives. The U.S. should also speed up and expand its program to develop and stockpile deeply penetrating explosive munitions. If a military bombing action were unsuccessful or only partially successful, Iran’s hand would be greatly strengthened. A public demonstration of America’s military deep penetration bomb capabilities might add significantly to the deterrence effort.

3. Stopping Iran militarily has more negatives than positives.

The military campaign would have to be large, estimated to be at least 260 2,000- to 5,000-pound precision-guided munitions, and it might fail to destroy all the significant capability. The U.S. military would have no good way to do bomb damage assessment without sending in ground troops at several sites for visual examination. Moreover, Iran’s air defense has been substantially upgraded, and consequently significant loss of life and aircraft can be expected. Additionally, Iran has installed sophisticated anti-ship missiles on the island of Abu Musa, thus controlling the critical Strait of Hormuz. Iran might retaliate by closing the strait, inviting an even wider war. Bombing Iran might mobilize their civilian population to back the radical regime to levels well beyond current support.

Can Iran be stopped? The short answer is yes. At the very least, Iran’s nuclear weapons program could be set back for years. However, it is easy to underestimate the level of force required. In addition to the bombing campaign to destroy the nuclear facilities, it would be advantageous to destroy Iranian air defenses, anti-ship missile capability and surface-to-surface missile capability. Although at least 260 large munitions would be required, the actual total could be 500 or more, including bombs and guided missiles. It also might be necessary to send in ground troops for damage assessment. This would involve a combat battalion at a minimum, probably airborne, for insertion and extraction.

It is generally assumed that U.S. military forces possess deep penetration bombs capable of reaching and destroying Iran’s underground facilities. If this is true, it is only marginally true. Iran has been continually upgrading the hardness of the fortifications for its nuclear facilities. If the attack is delayed for several more years, current weapons could become overmatched and obsolete. A continuing improvement program to extend the penetration capabilities of air-delivered bombs is called for.


There is little doubt that components of Iran’s nuclear activities are intended for production of weapons-grade plutonium and/or uranium. Three smoking guns are: å The heavy water plant and reactor at Arak.

å The large uranium gas centrifuge purification facility at Natanz.

å The 1,000 megawatt light water reactor at Bushehr.

In summary, the Iranian program cannot be considered cost-effective for civilian power purposes. Since Iran seems determined to produce weapons-grade uranium and plutonium in defiance of international constraints (and despite the recent NIE), it is appropriate to plan a military strike to disable its capability. The plan should be conditioned on continued Iranian noncompliance, and delayed as long as possible to give constraints and incentives a chance to work without permitting Iranian defenses to get too strong. That implies a reassessment of their actual bomb-building activities, a close scrutiny of the air defense buildup, as well as a look at Iranian efforts to harden their nuclear facilities. The attack plan should have international support politically and militarily. It should be predicated on the use of the most advanced conventional weapons both in inventory and in the developmental process. More urgency in developing improved penetrating weapons is called for. Some of the advanced weapons should be expended in a public demonstration to make it clear to Iran that their program is in jeopardy.

Marvin Baker Schaffer has been associated with the Rand think tank for more than 30 years. His specialties include commercial nuclear power, theories of warfare, counterterrorism and weapons analysis. He is the recipient of several professional awards, including the U.S. Army Meritorious Civilian Service Award.