Iran pushed with six other nations on Wednesday to resolve disputes over a reactor capable of generating plutonium, Deutsche-Presse Agentur reports.
The Persian Gulf nation's Arak heavy-water reactor came under discussion on the second day of a high-level multilateral meeting aimed at ending years of international enmity over Tehran's atomic activities. The United States and other Western powers believe the as-yet unfinished system could generate plutonium for possible use in weapons, though Tehran denies harboring nuclear-arms ambitions.
Speaking to a state news agency, Iranian Deputy Foreign Minister Abbas Araqchi said Tehran would not accept any halt in operations at the Arak site.
Alternatives could include lowering the site's maximum operating speed or changing its power source, analysts said in a Tuesday report by Reuters.
Former Obama administration WMD-nonproliferation czar Gary Samore said the five permanent U.N. Security Council member nations and Germany would likely demand "pretty extensive" modifications, while Iranian officials would seek "fairly cosmetic changes that would allow them ... to produce more plutonium."
Despite any differences, Iran's top diplomat on Wednesday said the negotiations were going "well," Reuters reported.
Iranian Foreign Minister Mohammad Javad Zarif added he was "optimistic" that the sides could finalize a long-term nuclear accord by July 20, when an interim deal is scheduled to lapse. Tehran is seeking relief from international sanctions in exchange for possible restrictions on its nuclear efforts.
In Washington, a large, bipartisan majority of U.S. senators signed a Tuesday letter urging President Obama to stick to several demands in the talks, including the principle that Iran has no inherent right to enrich uranium; that any possible paths to a plutonium- or uranium-based bomb be eliminated; that Iran give up its Fordow enrichment plant and Arak heavy-water reactor; and that "it fully explain the questionable activities in which it engaged at Parchin and other facilities."
Seventeen senators did not sign the missive: Tammy Baldwin (D-Wis.); Barbara Boxer (D-Calif.); Sherrod Brown (D-Ohio); Thomas Carper (D-Del.); Bob Corker (R-Tenn.); Dianne Feinstein (D-Calif.); Jeff Flake (R-Ariz.); Tom Harkin (D-Iowa); James Inhofe (R-Okla.); Tim Johnson (D-S.D.); Patrick Leahy (D-Vt.); Carl Levin (D-Mich.); Rand Paul (R-Ky.); Harry Reid (D-Nev.); Jay Rockefeller (D-W.Va.); Bernard Sanders (I-Vt.); and Brian Schatz (D-Hawaii).
Non-signers comprise 12 Democrats, four Republicans and one independent. Notables who opted out of the letter include Levin, the Senate Armed Services Committee chairman, and Paul, a possible contender for the 2016 Republican presidential nomination.