Iran announced today that it will soon exceed limits on its stockpiles of enriched uranium that it agreed to under the 2015 nuclear deal with the U.S. and other nations. The Trump administration pulled the U.S. out of the deal last year; other countries stayed in. And this new announcement is the latest sign that it might be falling apart altogether.

Joining us to discuss this is NPR's Geoff Brumfiel. He covers science and security. Hey, Geoff.

GEOFF BRUMFIEL, BYLINE: Hey, there.

SHAPIRO: What exactly did Iran announce today?

BRUMFIEL: Well, under the deal that was agreed to, there's a 300-kilogram limit on low-enriched uranium. That's all Iran is allowed to have. And they said they're going to start exceeding that limit within 10 days. Now, they made a number of other announcements regarding research reactors and future enrichment plans, but this is the main thing that's making headlines.

SHAPIRO: In practical terms, what does that 300-kilogram line mean? What does crossing it represent?

BRUMFIEL: Right. Well, this agreement was technically really complex. It was full of all sorts of figures and numbers. But basically, what it came down to was this. Iran, before the deal, was within a matter of weeks of getting the material it needed for a nuclear weapon, if that's what it wanted to do. So this deal dialed that back and made it so that, if Iran decided to start accumulating material, it would take at least a year. And the idea was that that would allow diplomats to act and try and stop Iran from going down the weapons route.

Now, this 300-kilogram limit was one of the numbers that was set to keep that year-wide gap open. It's not a hugely significant number in the sense that if they go to a 301-kilogram limit, it doesn't really change anything — or if they go to 302 kilograms of this low-enriched uranium. In fact, they'd need to get quite a bit. So the time won't start to come down right away. But it is a clear violation of the deal.

SHAPIRO: Given that President Trump pulled the U.S. out of this deal a year ago, why has Iran just now decided to do all this?

BRUMFIEL: Well, there's a couple of reasons. One, as you mentioned, the U.S. isn't the only party to the deal. And so after the U.S. pulled out, Iran wanted to give the other parties, which are Russia, Europe and China, time to maybe provide some sanctions relief, to provide it a reason to stay in. After a year, that hadn't happened. And so Iran has been putting pressure, particularly on Europe, to try and get something in exchange for agreeing to abide by the deal.

The other big thing that's going on is that the U.S. is dialing up this maximum pressure campaign. And Iran is kind of exerting the same campaign back. You know, they are starting to be increasingly provocative in a number of arenas, and the nuclear arena is one of those.

SHAPIRO: And does this mean that the deal is likely to totally fall apart soon?

BRUMFIEL: Not necessarily. I mean, Iran will be in violation. But as I said earlier, this is kind of a minor violation, and it can be dialed back pretty easily. Iran could get rid of this low-enriched uranium simply by diluting it with natural uranium. But if Iran makes good on some of the other steps it announced today, then I really think we're going to see this deal start to come under serious strain. And the other parties to it are unlikely to sort of stay in it, I think.

SHAPIRO: That's NPR's Geoff Brumfiel. Thanks, Geoff.

BRUMFIEL: Thank you.

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Words in This Story

stockpile – n. a large supply of something that is kept to be used in the future if necessary

uranium – n. a chemical element; a heavy, silver-white, radioactive metal, used mainly in producing nuclear energy.

sanction – n. an official order that limits trade, contact, etc. with a particular country, in order to make it do something, such as obeying international law

provocative – adj. intended to make people angry or upset; intended to make people argue about something