We’ve all seen the stories about the Iran nuclear deal, which was concluded on July 14 between Iran, Britain, China, France, Russia, Germany, the United States and the European Union. What does it really mean for U.S. and global security?
First, the forest:
The Iran nuclear deal is a good thing. The Joint Comprehensive Plan of Action (JCPOA), as it is officially titled, will make it more difficult for Iran to produce the fissile material needed to make a nuclear weapon, should it decide to do so.
And if Iran did decide to pursue a nuclear weapon, the deal will make it more likely that the world will have warning and the warning time will be longer than it would without a deal, providing more time for the international community to respond.
Thus, the deal is an important step forward in curbing Iran’s ability to produce a nuclear weapon.
Nuclear power and nuclear weapons
Let’s take a step further back. At the core of this issue is a problem inherent to nuclear power: some types of civil nuclear facilities can also be used to produce fissile material for nuclear weapons. In particular, almost all power reactors worldwide use uranium fuel that has been “enriched” to increase the concentration of the isotope U-235 above that in uranium found in nature. Natural uranium ore contains less than 1% U-235, and reactor fuel typically contains 3 to 5% U-235. Nuclear weapons typically use uranium that has been enriched to 90% or greater, but enrichment facilities producing low-enriched uranium (LEU) for fuel can be operated to produce weapons-grade highly enriched uranium (HEU) instead.
Reactors fueled with uranium produce plutonium as they use the fuel. Some countries have reprocessing facilities that extract the plutonium from spent fuel, and this plutonium can be used to build nuclear weapons as well as to fuel reactors.
The Nuclear Non-Proliferation Treaty (NPT) gives its signatories the right to develop nuclear power, including enrichment and reprocessing facilities. The International Atomic Energy Agency (IAEA) is charged with both facilitating nuclear power programs in these countries and carrying out inspections to verify that their facilities are not used to produce fissile material for weapons.
However, any country that possesses enrichment or reprocessing facilities will have the latent ability to produce fissile material for nuclear weapons. In other words, a country could throw out the IAEA inspectors and use these facilities for weapons purposes. The time needed to produce enough material for a nuclear weapon—the “breakout time”—will depend on the type and size of the facilities. But ultimately, the real barrier to a weapons program is not technical, but political.
The history of Iran’s nuclear program
The United States provided Iran with its first research reactor in 1967 as part of its “Atoms for Peace” program. The Shah had plans to build some two dozen nuclear power plants, and a German company was building Iran’s first two reactors at Bushehr when construction was halted by the Iranian revolution in 1979. One of the reactors was later completed by a Russian contractor, and began operating in 2011. Russia has a contract to provide fuel for the Bushehr reactor, and Iran will return the spent fuel to Russia.
Iran signed the NPT on the day it opened for signature in 1968, obligating it to not produce or acquire nuclear weapons. Accordingly, the IAEA applies “safeguards” to Iran’s nuclear facilities to verify that they are not being used for nuclear weapons purposes.
In 1997, the IAEA developed an “Additional Protocol” that NPT signatories can voluntarily adopt. The protocol requires the signatory state to provide additional information about its nuclear activities to the IAEA and allows the agency to conduct inspections at any facilities or sites that it suspects may be engaged in undeclared nuclear activities. The majority of NPT states have adopted the Additional Protocol, but Iran has not.
In 2002, an Iranian dissident group publicly revealed that Iran had two nuclear facilities under construction that it had not informed the IAEA about: a uranium enrichment facility in Natanz and a heavy water production facility in Arak. The latter would provide heavy water for the planned research reactor in Arak. U.S. and other intelligence agencies almost certainly knew about these facilities before their existence was made public.
At the time Iran was only required to inform the IAEA about these facilities six months before nuclear material was introduced into them, which had not yet happened, so it was still in compliance with its safeguards obligations. Nonetheless, these revelations put into motion a series of negotiations between Iran, the IAEA, and various European nations. As a result, in 2003 Iran agreed to inform the IAEA of any nuclear facilities as soon as it decided to build them. Iran also signed the Additional Protocol. However, it did not ratify the agreement, and suspended it in 2006, although it has continued to allow the IAEA to conduct its regular safeguards inspections.
The IAEA found that Iran had failed to report numerous nuclear-related activities, and in 2006 reported to the UN Security Council that Iran was not in compliance with its safeguards agreement. Shortly thereafter, the Security Council demanded that Iran suspend all enrichment activities and then imposed sanctions on Iran after it refused to do so.
In 2011, the IAEA also reported that it had evidence that Iran had conducted non-nuclear experiments relevant to designing nuclear weapons until 2003. In particular, the agency believes that Iran had conducted research on the high explosives needed to kick off a nuclear explosion at its Parchin military base.
Details of the Iran nuclear deal
Now for the trees:
Under the terms of the nuclear deal, Iran will accept significant constraints on its nuclear program for the next 10 to 15 years (recall that the NPT places no restraints on the peaceful nuclear programs of its signatories). It will sign and implement the Additional Protocol, the provisions of which will extend indefinitely. It will also allow IAEA monitoring and inspections beyond those required by the protocol for the next 15 to 25 years.
There are several potential pathways for Iran to produce the fissile material needed for a bomb—it could enrich uranium using known facilities, produce plutonium using known facilities, or operate covert facilities. The deal constrains those pathways for the next 10 to 15 years.
Iran has uranium enrichment facilities at Fordow and Natanz, with a total of some 19,000 centrifuges. Under the deal, Iran will disassemble and store roughly 13,000 centrifuges. It will not enrich uranium at Fordow, but will maintain 1,000 centrifuges at that facility, some of which will be used to produce stable isotopes for research or commercial purposes with the remaining kept idle. It will continue to enrich uranium at Natanz, but only using about 5,000 of its first-generation IR-1 centrifuges, and only to an enrichment level of 3.67 percent.
But perhaps most significantly, Iran will reduce its current stockpile of about 10,000 kg of low-enriched uranium (LEU) to 300 kg of 3.67 percent LEU for 15 years. It is much easier to produce weapon-grade uranium if you start with 3.67 percent LEU rather than natural uranium—by about a factor of three. By essentially eliminating Iran’s stockpile of LEU, the deal extends the time it would take Iran to produce enough material for a weapon.
How long would it take for Iran to acquire enough HEU to build a bomb, if it decided to leave the NPT and threw the inspectors out?
There is no precise answer to this question, because it depends on a host of factors that are not precisely known—such as the amount of HEU required for Iran’s bomb design, the performance of its centrifuges, and how quickly Iran could reinstall the centrifuges that will be disassembled and in storage under the terms of the deal. The administration states that currently, it would take Iran 2-3 months, and that under the agreement the “breakout time” would increase to a year. A breakout time of roughly a year is consistent with the following reasonable assumptions: (1) a nuclear weapon would require roughly 28 kg of weapons-grade HEU (90% enriched), which is the standard IAEA assumption; (2) the average capacity of Iran’s IR-1 centrifuges is about 0.75 SWU/year, as indicated by the latest data from Iran’s May 2105 report to the IAEA; and (3) Iran would use all 6,000 installed IR-1 centrifuges at Natanz and Fordow, but could not reinstall the 13,000 disassembled centrifuges within a year.
While the breakout time would vary somewhat depending on the details, it will be significantly longer under the deal than it is today.
What if Iran decided to instead follow a plutonium route to a bomb? Iran could produce plutonium at its Arak research reactor, now under construction. While all reactors fueled with uranium produce plutonium, some types of reactors produce it at a higher rate than others. As initially configured, the Arak reactor would produce enough plutonium in its spent fuel for roughly one nuclear weapon each year. However, the spent fuel would need to be reprocessed to extract the plutonium, and Iran has no reprocessing facility.
Under the agreement, Iran will destroy the existing reactor core, and replace it with one of a new design, which would require ten years to produce enough plutonium for one nuclear weapon. Iran will ship all spent fuel out of the country for the lifetime of the reactor.
Moreover, under the deal Iran has agreed to not reprocess or engage in reprocessing R&D for 15 years, and states that it does not intend to do so after that.
Finally, what if Iran tried to build a covert enrichment or reprocessing facility? Under the agreement, the IAEA will monitor all uranium ore mined in Iran or imported, cutting off Iran’s ability to supply uranium to any covert enrichment facility. In addition, Iran would not be able to surreptitiously acquire spent fuel to reprocess since its reactors will be monitored.
Moreover, under the agreement, the IAEA has the right to inspect any site where it suspects Iran is engaged in prohibited activities. An inspection must take place within 24 days from the time of the request, and any work with fissile material would leave a detectable trace.
Where to go from here?
The agreement puts strong, verifiable restrictions on Iran’s nuclear program, and the U.S. Congress should endorse it.
In addition, the United States and other countries can do more to widen the gap between nuclear power and nuclear weapons—in Iran and elsewhere.
The United States does not reprocess its spent fuel, and this policy has helped constrain reprocessing by other countries. The United States should continue to work to persuade other nations to forgo reprocessing.
As several researchers at Princeton—Alexander Glaser, Zia Mian and Frank von Hippel—advocate in an article in Science, the parties to the Iran agreement should invest in Iran’s enrichment facility so that it becomes multinational. And the United States should abandon its plan for a new national enrichment facility, instead continuing to rely on Urenco, a company owned by Britain, Germany and the Netherlands. A U.S. commitment to multinational enrichment would help create a regime in which all enrichment facilities were multinational and, as the Princeton group put it, “in which nuclear power rules apply equally to all states.”