A CONVERSATION: The science behind the deal

The main U.S. objective of the deal with Iran is to decrease the riskiness of Iran’s civilian nuclear program to a point that (1) future nuclear weapon production would be unlikely and (2) if Iran does cheat, it would be detected with reasonable certainty.

So have the objectives been achieved in the deal signed July 14?

Under the nuclear Non-Proliferation Treaty (NPT) signed by all but a handful of the world’s countries, all countries who have signed it have obligations. Countries that did not test nuclear weapons before 1967, for example, are obligated to not seek nuclear weapons in return for unhindered development of their nuclear energy programs. (Note that India, Pakistan and Israel are not NPT signatories.)

The problem is that it is not always clear whether a nuclear program is civilian or hides a military purpose. For example, in 1955 Canada built a 40 megawatt reactor for India in return for a promise that it would be used exclusively for peaceful purposes. However, in 1974, India broke that promise by conducting a nuclear test using plutonium (the explosive fuel of a nuclear bomb) produced with the same reactor.

The current Iranian reactor at Arak is of a similar type to that in India -- and of the same power. Iran has repeatedly assured the International Atomic Energy Agency (IAEA) of the reactor’s civilian use, but the P5+1 -- the five permanent members of the UN Security Council plus Germany, which brokered the deal with Iran -- are not willing to take that chance. For this reason, the final agreement has measures to ensure the Arak reactor will not produce weapons-grade plutonium.

In addition, over the past decade, Iran has invested heavily in uranium enrichment infrastructure, constructing several large enrichment plants. All of these facilities are presently under IAEA safeguards. In the enrichment process, the more useful isotope uranium-235 is increased in proportion relative to the other uranium isotopes. Most power reactors use fuel containing uranium enriched to 3 percent to 5 percent uranium-235, whereas nuclear weapons use uranium that has been enriched to as high as 90 percent.

However, the enrichment process is not linear -- it takes far more work to enrich uranium to 5 percent then it does to enrich from 5 percent to 90 percent. And herein lies the problem. The P5+1 needs to be assured to reasonable certainty that even if Iran expels inspectors and enriches enough uranium for a bomb with current facilities, that time is long enough that a sufficient response can be organized. This “breakout” time is currently two to three months, but is extended to about a year in the final agreement.

The last route to a bomb is the possibility of the use of clandestine facilities to enrich uranium or extract plutonium. To close this gap, Iran will apply enhanced safeguard measures to its comprehensive safeguards agreement called the “Additional Protocol,” which is in force in 126 countries around the world. This agreement will not only severely limit Iran’s possibility to produce nuclear weapons but will open the doors to increased investment and herald a new era of international cooperation in the region.

Congress will now have 60 days to scrutinize the accord.