Seven problems with John Kerry's Iranian nuclear clock

US Secretary of State John Kerry has repeatedly pledged that the prospective nuclear agreement being hammered out between the P5+1 world powers and Iran will extend the Islamic Republic’s “breakout time” – how quickly it can produce sufficient fissile material for an atomic bomb should it make a rush to build one – from “about two months” to “a minimum of a year.” While U.S. officials have been tight-lipped about details of the talks, this seemingly tangible metric is clearly going to be the big selling point when Kerry seeks to win support for an agreement from a skeptical Congress.

Kerry gets his numbers by calculating how long it would take Iran to produce a bomb’s worth (around 25 kg) of weapons grade uranium (WGU) given the number and types of centrifuges it currently has installed (18,458 first generation IR-1s and 1008 IR-2s) and operating (around 10,180 IR-1s) at its two enrichment plants, and the amount of under 5% low enriched uranium (LEU) it has on hand to use as feedstock.  Cap these variables at whatever levels are needed to lift the other side of the equation to a year, put in place an augmented inspections regime to make sure Iran isn’t cheating, and voila … ten months back on the clock.

Well, not exactly.  A multitude of “ifs”, “ands”, and “buts” render Kerry’s pledge all but meaningless.

There is No Clock

While nominal breakout time, a simple function of overall enrichment capacity and available feedstock, is convenient shorthand for a country’s ability to produce a weapon, it isn’t a meaningful threshold in a real-world breakout attempt. Producing one bomb’s worth of WGU – what the International Atomic Energy Association (IAEA) terms a significant quantity (SQ) – wouldn’t be much of an achievement, as the Iranians can’t put it on a warhead (assuming they’ve designed one) without first conducting a nuclear test (lest no one believe they’ve split the atom), while carrying out a test without having stockpiled enough material for at least one weapon would announce their aggressive intentions to the world without simultaneously acquiring a nuclear deterrent.  To be sure, an Iranian dash to produce one SQ of WGU would be a proliferation threat, but that doesn’t mean it would make sense for the Iranians (unless their objective is to deliberately provoke military intervention).

Iran’s effective breakout time – to enrich enough WGU to be reasonably certain of ending up with a deployable nuke – depends on how certain the Iranians want to be.

Two bomb-loads of WGU would be sufficient to acquire a modicum of nuclear deterrence only if the test is successful, but that’s hardly a sure thing (North Korea had two failed tests in a row, albeit with plutonium bombs).  Even three would be a crapshoot given Iran’s poor track record of getting things right the first time around in its nuclear program.

This is an important distinction because the Obama administration’s public rationale for accepting an inferior deal feeds off of the common misconception that Iran is eight weeks away from a nuclear weapon (almost anything looks better than that). The Iranians are portrayed as too close to the finish line to be pushed or prodded most of the way back.  Press too hard, Kerry has suggested, and Iran might "rush towards a nuclear weapon."  In fact, it’s not too late for the international community to deny Iran a viable chance of succeeding in a future breakout attempt.

Untested “Disablement”

Kerry’s post-agreement breakout time calculations assume that Iran does not bring more centrifuges into operation for a whole year after kicking out inspectors and beginning its sprint for a nuke.  Dismantling the large majority of Iranian centrifuges that fall outside of the agreed-upon quota could ensure this, but Iran has long insisted that it will never destroy any of them.  Instead, the White House is proposing that excess centrifuges and associated equipment merely be disconnected, removed to IAEA-monitored storage offsite, and disabled in some way that cannot be quickly reversed (but without removing components that would render them permanently inoperable).

Although U.S. nuclear scientists are said to have studied a range of technical measures designed to make the process of reconnecting centrifuge cascades and piping more time-consuming, “disablement” is not an exact science.  The only real-world application of such measures thus far was in North Korea, which “was able to reverse many of these steps faster than expected,” according to the Institute for Science and International Security (ISIS). In the case of Iran, analysts at ISIS were unable to identify even a hypothetical disablement process that would take more than six months to reverse. Considering that the Iranians would be sure to immediately begin training personnel to reverse the disablement steps, there’s little reason to be confident that such technical speed bumps can prevent a ramp up of Iranian enrichment capacity for an entire year if excess centrifuges are left intact.

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