article_snippet: Two core issues are still unresolved: 1) Limits on Iranian research and development on advanced nuclear technology in the end years of the deal; and 2)
article_snippet: Many are related to proliferation and transfer of missile technology and are tied to certification by the U.N. nuclear watchdog, the International Atomic Energy Agency, that Iran's nuclear program does not have a military dimension.
article_snippet: Iran also wants the ability to continue to research and develop more advanced centrifuges while the deal is in effect.
article_snippet: Those machines can enrich uranium much faster than Iran current machines.
article_snippet: U.S. and European officials worry that could enable Iran to quickly produce enough uranium for a nuclear weapon.
article_snippet: Diplomats said Iran has agreed to a cap of fewer than 6,000 centrifuges that Iran can operate to enrich uranium, a process that can lead to weapons-grade material.  
article_snippet: Iran currently runs about 10,000 centrifuges, but Iran has around 19,000 in Iran stockpile.
article_snippet: U.S. officials maintain the number is abstract, because there will be other restrictions on the levels of enrichment and type of centrifuges Iran can operate, which U.S. officials believe will extend the time Iran would need to have enough fissile material produce a nuclear weapon -- known as the "break-out time"  -- to at least a year.
highlights_snippet: One key sticking point: What would be the limits on Iranian nuclear research?
  