(Majid Asgaripour/ File, Associated Press)

Steve Fetter is one of the country’s foremost experts on nuclear proliferation, and served until recently as assistant director at-large in the White House’s Office of Science and Technology Policy. Yesterday, I asked him five questions about the technical problems at issue in the current negotiations over the future of Iran’s nuclear program. His answers are below.

(1) Some people have expressed concern that Iran has enriched uranium to a level of about 20% uranium 235. Why is this level of enrichment a red line for at least some of the interested parties?

People are concerned about Iran’s production of uranium enriched to 20% U235 because a stockpile of this material could be further enriched to weapon-grade uranium (90% U235) very quickly — much more quickly than if Iran started with natural uranium (0.7% U235) or the low-enriched uranium used to make power reactor fuel (4% U235). Using the 10,000 centrifuges that Iran currently operates, it would take over 6 months to produce one bomb’s worth of weapon-grade uranium starting with natural uranium, but only 20 days starting with 20% enriched material.

Iran claims that the 20% enriched material is being produced to fuel a small research reactor. Some of this material has been used to fabricate fuel plates for the reactor. If all of this material was made into fuel plates, it would be less accessible for further enrichment to weapon-grade, particular if Iran did not develop the chemical processes that would be required to convert the fuel plates to the form necessary for enrichment.

(2) Another key issue in the negotiations is the status of the Arak heavy water reactor. How would this reactor affect Iran’s ability to build nuclear weapons if it came online?

Such reactors are ideally suited for the production of high-quality plutonium for nuclear weapons. Indeed, India and Israel used similar reactors to produce plutonium for nuclear weapons. The Arak reactor could produce more than one bomb’s worth of plutonium per year, but Iran would also need to build a special plant to separate the plutonium from the highly radioactive spent fuel, and there is no indication that Iran has or is planning to build such a facility.

There may be ways to modify the Arak reactor so that it would produce less or lower-quality plutonium. Because Iran claims that the reactor will be used for the production of medical isotopes, another possibility would be to use alternative medical isotope production technology that would pose much smaller risks of nuclear proliferation.

(3) How does Iran’s progress over the last couple of years in enriching uranium and building the new reactor affect the timetable for negotiations?

Iran’s enrichment program has grown steadily, from a single cascade of 164 centrifuges in 2003 to more than 10,000 operating centrifuges today. The Arak reactor will not be operational for at least six months. It is still possible to reach an agreement that would place significant limits on Iran’s capacity to produce weapon-usable nuclear materials, particularly if Iran agrees to freeze the program while negotiations continue. Absent a freeze or agreed-upon limits, Iran will continue to expand its program, making meaningful limits more difficult to achieve.

(4) What are the issues at stake in the wording over the “right to enrich”?

In signing and ratifying the Non-Proliferation Treaty, Iran agreed not to seek nuclear weapons and to accept IAEA safeguards to ensure that all nuclear facilities and materials are being used only for peaceful purposes. The treaty recognizes “the inalienable right…to develop research, production and use of nuclear energy for peaceful purposes,” which Iran has interpreted as a “right to enrich.” But the Treaty does not recognize an absolute right to enrichment; all nuclear activities are conditional on the commitment not to seek nuclear weapons. Any “right to enrich” must be tied to measures to ensure that Iran is not seeking and will not seek nuclear weapons.

(5) Presumably, given Iran’s insistence on its right to peaceful nuclear development, any final deal will involve an inspection and monitoring regimen. Given past experience, how is such a regimen  likely to work?

The IAEA has extensive experience in implementing inspection and monitoring regimens that give high confidence that declared nuclear facilities and materials are being used only for peaceful purposes. Concerns focus mainly on the possibility of “break-out” and undeclared facilities. “Break-out” refers to the possibility that Iran could withdraw from the non-proliferation treaty, expel IAEA inspector and attempt to use declared facilities to produce material for nuclear weapons. An agreement could limit Iran’s capabilities so that it would take 6 to 12 months to produce one or two bomb’s worth of material, giving the international community adequate time to respond. And by implementing a vigorous safeguards program, the IAEA would over time gain confidence that there are no militarily significant undeclared nuclear activities.


(Steve Fetter/University of Maryland)

Steve Fetter is the Associate Provost for Academic Affairs at the University of Maryland. He has worked on nuclear arms control and nonproliferation as well as a variety of energy issues. He served as assistant director at-large in the White House’s Office of Science and Technology Policy from 2009-2012, and directed OSTP’s environment and energy division from 2011-2012. His books include Toward a Comprehensive Test Ban, The Future of U.S. Nuclear Weapons Policy, The Nuclear Turning Point, Monitoring Nuclear Weapons and Nuclear Explosive Materials, Effects of Nuclear Earth-Penetrator and Other Weapons, and Climate Change and the Transformation of World Energy Supply.