Hamid Foroutan / AP
Iran is about to cross an important frontier of the nuclear agreement with the US and other powers in 2015. As soon as it announces on Thursday that its uranium reserves have exceeded its limits set by the agreement.
"I think it's an important bridge they need to go through," says David Albright, president of the Institute for Science and International Security, which oversees the Iranian nuclear program. Albright and other experts believe that exceeding the threshold could mark the beginning of the end of the nuclear agreement that the US signed in May 2018.
The nuclear deal is full of facts and figures, but its purpose is simple: to slow down the Iranian nuclear program. Before the deal, Iran had received enough highly enriched uranium for a nuclear bomb within a few weeks, if he so wished. The deal has shifted that timeframe from weeks to about a year.
As part of the multilateral joint comprehensive action plan, Iran has been forced to get rid of many low-wage projects. enriched uranium. Low-enriched uranium will be held at levels far below the 90% level deemed appropriate for the construction of nuclear weapons. However, large amounts of poorly enriched uranium can be relatively quickly refined into bombs. The deal limited the Iranian stock of low-enriched material to just 300 kilograms or 661 pounds.
But that was it then. Last year, President Trump retired from the business. Without the economic benefits promised to Iran in return for curtailing its nuclear program, it has begun to withdraw the agreement. In May, she announced that she would begin to accumulate more low-enriched uranium.
"We will cross the 300 kg border," said Behrouz Kamalvandi, spokesman for the Iranian nuclear energy organization, to reporters last week. According to the organization, Iran will cross the border on June 27th.
From a technical point of view crossing the border is not that big a deal. Low-enriched uranium can not be converted directly into a weapon.
"It will not change much," he says. "You have to produce about a ton or a thousand kilograms before you get really nervous."
But the 300 kg. Limit is not the only number in the agreement. Iran has warned that it will cross other borders in the coming weeks.
He plans to increase the enrichment of his uranium fuel and reverse the planned changes to a nuclear reactor in Arak.  "Given threats that Iran might violate some of the core principles of the agreement, this agreement on life-support could be dead," said Corey Hinderstein, vice president of the Nuclear Threat Initiative on international fuel cycle strategies , As a US Department of Energy official, she oversaw parts of the nuclear deal by 2017.
Much of the reason for the breakup is due to the sanctions imposed by the US last year. They punish anyone doing business with Iran, including companies in other places that remained in the agreement: Europe, China and Russia.
European companies had hoped to do business with Iran. But in the face of US sanctions, "We've seen these companies step down and say, 'We can not afford to lose the US market,' says Hinderstein.
Iran is now exceeding one line in the deal European negotiators are seeking to complete a package of humanitarian aid by the beginning of July, according to Aniseh Bassiri Tabrizi of the UK's Royal United Services Institute, in an effort to put European nations under pressure to deliver promised economic relief address these issues, "says Tabrizi.
If this aid, including medical supplies, can be provided without US objections, it may open up the possibility of Iran gaining more economic benefits. But Tabrizi says it remains to be seen if it will be enough.
"Iran has made it clear that it must continue to export oil in order to see the incentive to remain a party to the nuclear agreement." she says.
Currently, says Hinderstein, Iran is still about a year away from gathering material for a bomb – should he decide to. "We still have some time for work," she says.
But with every frontier that crosses Iran, the timeline becomes shorter and the nuclear deal fades away.