Understanding Iran’s nuclear program

When negotiations began in 2003 between Iran and three European powers over its nuclear work, Tehran was struggling to assemble 164 uranium-enrichment centrifuges. The current round of negotiations that concluded successfully in Vienna on July 14, 2015, saw Iran in possession of more than 18,000 centrifuges. Even then, a nuclear-armed Iran was neither imminent nor inevitable.

Although a number of additional matters delayed the achievement of a deal at the eleventh hour, four key issues were at the core of international concerns over Tehran's nuclear activities:

Concern 2: Fissile material stockpile

Accumulation of enriched uranium in Iranian facilities is another source of concern, as such material could more rapidly be further refined to reach weapons grade (above 80 percent). As of Aug. 28, 2013, Iran had 6,774 kilograms of 3.5 percent and 185 kilograms of 20 percent enriched uranium.

With further enrichment — if Iran expelled inspectors — that stockpile could be turned into material for five nuclear weapons in six months to a year. Iran's accumulation of uranium enriched to 20 percent is particularly worrisome, as that level of enrichment reduces by more than 90 percent the time it would take to turn natural uranium into bomb material.

Tehran, however, has thus far kept the size of its 20 percent stockpile below the red line set last year by Israel's Prime Minister Benjamin Netanyahu, which is about 250 kilograms (enough for one bomb if re-enriched). It has done this by oxidizing enriched uranium and converting it into fuel rods for reactors, a process that renders weaponization far more difficult.

Concern 3: Heavy-water reactor

Iran is constructing a heavy-water research reactor in the city of Arak. The reactor uses natural uranium as fuel; once operational, it will produce about 9 kilograms of plutonium every year, which is sufficient for 1 1/2 bombs. This can open a second path — followed by most nuclear proliferators — to nuclear weapons.

Separating plutonium from a reactor's spent fuel rods, however, requires a reprocessing facility that Iran neither currently has nor has demonstrated any intention of building. But this might not matter to Israel, which twice before has attacked suspected reactors in countries in the region — in Iraq in 1981 and in Syria in 2007 — before their completion, since striking an operational reactor would result in an environmental catastrophe.

Concern 4: Past activities

Iran's uranium enrichment program was born in secret through the acquisition of technical drawings, manufacturing instructions and samples of components for centrifuges from the father of Pakistan’s atomic bomb and infamous proliferator, AQ Khan.

Iran's construction of undeclared nuclear enrichment and heavy-water facilities was exposed in 2002 by an exiled opposition group, triggering an international crisis.

Nine years later, the IAEA detailed charges that before 2003, Tehran experimented with technologies critical for the development of nuclear warheads, warning that some such research work may be ongoing.

Reason 1: International inspections

No state has built nuclear weapons while under scrutiny of in-country IAEA inspectors. In fact, of the five countries that developed nuclear weapons in the past four decades, four (Pakistan, India, South Africa and Israel) were not signatories of the Nuclear Non-Proliferation Treaty and therefore were never under IAEA inspection, and North Korea expelled the inspectors before testing its nuclear device.

IAEA inspectors visit Iran's nuclear facilities almost weekly. And time favors the inspectors. Alarmist warnings about Iran reaching breakout capability — the ability to process low-enriched uranium into weapons grade fissile material — omits the simple fact that if Iran decided to produce weapons-grade uranium, it would have to reconfigure its centrifuge cascades.

That process usually takes one to two weeks and would undoubtedly be detected by the IAEA. It is extremely unlikely that Iran could even buy time by delaying the inspectors' visit through pretexts, given that such action is likely to prompt international opprobrium and even serve as a casus belli.

Iran can’t begin producing bomb material without tripping a wire that would give the other nations several weeks to react before it could create fissile material for a single bomb, and turning such material into a deliverable warhead would take would take at least a year.

Reason 2: The cost-benefit rationale

A country reaches the military nuclear threshold when it has the capacity to manufacture one or more nuclear weapons within weeks. But it defies strategic logic for a country to accept risks of a military confrontation with more powerful adversaries simply in order to develop a single crude nuclear device.

To acquire real nuclear deterrence, Iran would need a deployable nuclear arsenal, not just enough material for one bomb. It would need to test a nuclear device and marry it with an appropriate delivery vehicle. And it is nearly impossible that Iran could reach such a capability in less than a year without being detected and stopped by the U.S. or Israel.

All previous Iranian efforts to conceal nuclear activities were exposed in their nascent stages. Likewise, it is useful to remember than given the United States' significant standing capabilities in the region, it would take less than 24 hours for the U.S. to launch military strikes in response to any such undertaking.

Reason 3: The lack of a political decision

Iranian leaders have pledged to never make nuclear weapons, which they consider a violation of Islam. But more important, according to James Clapper, the United States' director of national intelligence, Iran’s leaders have not yet decided to build nuclear weapons. The U.S. and Israeli intelligence communities are reasonably confident of their ability to detect such a decision.

In contrast to lack of evidence of any political decision by Iran to cross the nuclear Rubicon, the Iranian government has provided plenty of evidence that it wants a nuclear deal. Besides verbal declarations by its leadership, a number of Iranian decisions in managing nuclear work have been read as signaling a desire to avoid provoking confrontation. For example, Tehran has converted approximately 60 percent of its 20 percent enriched uranium stockpile to uranium oxide, which is less prone to proliferation, as its further enrichment requires weeks of chemical processing detectable by the IAEA.