News

AP EXPLAINS: Science of uranium enrichment amid Iran tension

AP EXPLAINS: Science of uranium enrichment amid Iran tension
World
NEW YORK - Iran made a veiled threat this week to enrich uranium stocks closer to weapon-grade levels amid rising tensions in the region.

That would mean going beyond the level of potency allowed by the 2015 nuclear agreement with world powers, which the U.S. withdrew from last year. Tehran is threatening to resume higher enrichment on July 7 if no new agreement is reached to provide relief from U.S. sanctions.

Enriching a supply of uranium means boosting its concentration of the type of uranium that can power a nuclear reaction. That type, or isotope, is called U-235. Enrichment basically means stripping away atoms of another isotope, called U-238.

When uranium is mined, it typically has about 140 atoms of this unwanted isotope for every atom of U-235, notes Christopher Chyba of Princeton University. Refining it to a purity of 3.67%, the level now allowed by the nuclear deal, means removing 114 unwanted atoms of U-238 for every atom of U-235.

Boosting its purity to 20% means removing 22 more unwanted isotopes per atom of U-235, while going from there to 90% purity means removing just four more per atom of U-235, he noted. Ninety per cent is considered weapons-grade.

ARTICLE CONTINUES BELOW

So once one achieves 20% purity on the way to 90%, “you’re most of the way there already,” Chyba said.

Iran’s Supreme Leader Ayatollah Ali Khamenei reportedly said Tuesday that achieving 20% “is the most difficult part ... The next steps are easier than this step.” Iran is not known to have enriched beyond 20% previously.

Matthew Bunn at Harvard’s John F. Kennedy School of Government said the same centrifuge technology used to reach 3.67% can be used to drive enrichment to 90%.

Once Tehran had enough uranium enriched to 20%, it would only be weeks away from a bomb if it decided to build one, he said. A bomb’s worth of highly enriched uranium “could be the size of a very large grapefruit,” Bunn said.

Iran says it has never sought nuclear weapons. But Western officials and experts say that prior to the nuclear deal, Iran had a breakout capability of just a few months if it were to decide to build a bomb. The Obama administration, which negotiated the deal, said it extended that breakout period to one year or more, giving Western powers more time to detect any such decision and respond to it.
Read more on Toronto Star
News Topics :
Similar Articles :
World
TEHRAN, Iran AP — Iran will break the uranium stockpile limit set by Tehran’s nuclear deal with world powers in the next 10 days, the spokesman for the country’s atomic...
World
Iran stepped up production of enriched uranium, which is used to make reactor fuel and potentially nuclear weapons, in response to reinstated US sanctions. European nations have warned that any...
World
The EU has strongly urged Iran to reverse its decision to raise the level at which it enriches uranium beyond that allowed by a 2015 nuclear deal. Spokeswoman Maja Kocijancic...
World
VIENNA Reuters Iran said on Wednesday it will accelerate its enrichment of uranium as of Thursday, a date it has previously suggested could see its stock of enriched uranium...
World
GENEVA Reuters Iran told European powers on Monday it would further reduce compliance with its 2015 nuclear deal in about a month’s time if they were still failing to...