Following two days of face-to-face talks in Geneva this week, a US official briefed assembled members of the press on progress in nuclear talks between Iran and the P5 + 1 (United States, China, United Kingdom, France, Germany, and EU). The briefing revolved around a stunning revelation about the recent direction of the talks, mainly that US negotiators have apparently agreed in principle to a two-tiered set of restrictions on Iran’s nuclear program.

Details are vague, but the deal currently being tabled seems to restrict Iran’s nuclear capacity in strict terms for 10 years before gradually loosening restrictions over a five-year period. Over the initial 10-year period, Iran would be allowed to operate 6,500 IR-1 centrifuges to further its peaceful nuclear development.

As of May 2014, Iran was operating around 10,000 IR-1 centrifuges and about 1,000 IR-2m centrifuges (which can enrich uranium up to five-times more efficiently than the older IR-1 models). According to a study by Arms Control Today, this combined capacity would allow for the production of a nuclear weapon within 3-4 months.