Iran's enriched uranium

Embedded above is a screencap from an impressive New York Times article explaining how Iran accumulated 11 tons of nuclear material.  

The graph depicts uranium at various "grades" from low-level (grayish) to enriched (darker) and weapons grade (blackish).

"As the stockpile kept growing, the Obama administration began talks to curb it.  In 2015, Iran and six nations led by the United States reached an accord that limited the purity of its enriched uranium to 3.67 percent and the size of its stockpile until 2030... Iran lacked a single bomb’s worth of uranium in 2018, when Mr. Trump withdrew the United States from the pact and reimposed a series of tough economic sanctions."

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