“The breakdown in talks in Pakistan over the weekend occurred over a US insistence that Iran suspend its uranium enrichment programme for 20 years in exchange for sanctions relief, followed by Tehran’s refusal to agree to a moratorium on enrichment beyond five years.”

“Iran is believed to have about 440kg (970 pounds) of uranium enriched to 60 percent – the level at which it becomes much faster to get to the 90 percent threshold needed to produce a nuclear weapon.”

“That amount is enough, theoretically, to produce more than 10 nuclear warheads, IAEA chief Rafael Grossi told Al Jazeera in early March.”

“The IAEA says uranium is considered low-enriched if its isotopic proportion of U-235 remains below 20 percent. This is generally used in civilian, commercial reactors to generate power for homes and industries. It is considered highly enriched if its isotopic proportion is beyond 20 percent.”

“Enrichment needs to cross 90 percent for it to be considered weapons-grade.”

“Under the JCPOA, Iran agreed to cap its U-235 enrichment levels to 3.67 percent for 15 years. It also agreed not to build new centrifuges for 10 years, and to reduce the number of existing centrifuges over that decade. Enrichment — up to 3.67 percent — was only permitted at the Natanz facility. And Iran’s enriched uranium stockpile would be kept under 300kg (660 pounds).”