Why did Iran agree to send the bulk of its low-enriched uranium out of the country and remove the core of its Arak reactor? Those actions significantly lengthen the time it would take to build up a nuclear weapon program.

Siegfried Hecker, CISAC senior fellow and former Los Alamost National Laboratory director, shares his personal view in the Bulletin of Atomic Scientists: http://thebulletin.org/iran-nuclear-option-more-trouble-it-was-worth9064