Iran nuclear talks: What you need to know

U.S. Secretary of State John Kerry acknowledged on July 9to the journalists gathered in Vienna for the nuclear talks with Iran that it's "difficult" for them, waiting and wondering whether negotiators will succeed in hammering out a final agreement.

Talk havecontinued past the much extended deadline,last pegged at July 13.

In those brief remarks to journalists on Thursday, Kerry said the negotiators"are making real progress towards a comprehensive deal" but "some of the tough issues remain unresolved."

Like most long-running negotiations, following the developments coming out of the talks can also be difficult. Here's a synopsis of the primary issues, the major sticking points, and what's at stake.

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Why are the talks happening?

The United States and other Western governments fearthat Iran wants the capability to build nuclear weapons, something Tehran denies. The deal is supposed to allay those suspicions.

In July 2006, the UN Security Council demanded Iran suspend its uranium enrichment program, adding sanctions would follow if Iran didn't comply. That December, the Security Council banned the sale of nuclear-related technology to Iran and froze assets belonging to key companies and individuals involved in Iran's nuclear program.

Uranium enrichment continued in Iran, and the UN's International Atomic Energy Agency complained about insufficient co-operation from Tehran and expressed concerns about potential military uses of Iran's nuclear program. The UN, the U.S. and the EU imposed further sanctions, including ones on individuals and companies tied to Iran's nuclear program.

Iran wantedthe sanctions, which have cost the Iranian economy tens of billions of dollars, lifted. By 2013 Iran was sitting across the negotiating table from the U.K., France and Germany (with whom they had been negotiating since 2003), as well as the U.S., Russia and China.

Didn't they already reach a deal?

There have been several agreements reached in relation to Iran's nuclear program.

In November 2013, the two sides reached a Joint Plan of Action under which Iran agreed to curb its nuclear work in exchange for modest sanctions relief.

Iran said it would stop enriching uranium abovefive per cent weapons-grade uranium is enriched to 90 per cent and neutralize its uranium stockpile that had been enriched abovefive per cent. Tehran also agreed to halt construction of a heavy water nuclear reactor at Arak.

The two sides committed to reaching a comprehensive agreement within a year, but that deadline has since been extended fivetimes.

In April they reached agreement on the framework for a Comprehensive Joint Plan of Action, or final agreement.

The U.S. says it would take Iran around two to three months to build a nuclear weapon now. Under the terms of the new deal, it would take Iran at leasta year to build an atomic bomb.

What are the terms of agreement?

In addition to the limits on enrichment levels, agreement has been reached on:

• Centrifuges: Iran can only keep installed6,104 centrifuges for uranium enrichment and they must be theleast efficient model. Iran has about 19,000 installed now at two locations.

• Fordow fuel enrichment plant: At this underground facility near Qom, Iran cannot enrich uranium or conduct uranium-related research and development for at least 15 years. The site becomes a nuclear physics and technology research centre instead.

• Arak heavy water reactor: It will be rebuilt so Iran cannot produce weapons-grade plutonium, and it cannot build another heavy water reactor for 15 years.

• Inspections: The IAEA will continue inspections in Iran and will be allowed to investigate suspicious sites or allegations of covert nuclear work. Suspicions about past Iranian nuclear weapons work will be investigated.

• Sanctions: The U.S. and the EU will suspend nuclear-related sanctions after the IAEA verifies Iranian compliance. If Iran violates the deal, sanctions can be re-imposed. UN Security Council resolutions on Iran will be lifted simultaneously with Iran fulfilling its commitments under the deal. Disagreements will go to a dispute resolution process.

What remains to be resolved?

• When the sanctions get lifted: Iran wants that to happen as soon as there's a deal. The Western governments want the sanctionsremoved gradually, as Iran takes steps to constrain its nuclear program.

• Which sanctions get lifted: Iran is apparently pushing for the lifting of more than just the sanctions imposed in response to its nuclear program. The U.S. wants to keep the separate block of sanctions against Iran's ballistic missile program, unless Iran suspends the program, and keep punishing Iran for its human rights and terrorism records.

• Inspections: Iran won't agree to inspections of military installations or allow Iranian scientists to be interviewed. The U.S. wants monitors to be able to investigate, within a reasonable time, whatever they deem necessary.

• Uranium stockpile: Iran agreed to reduce its stockpile of low-enriched uranium. Iran wants to do that by converting it to a level of enrichment that cannot easily be weaponized,but the IAEA says Iran cannot succeed in doing that in time unless it ships most of that uranium out of the country, which Iran doesn't want to do.

• Uranium enrichment: In April 2015, Iran agreed to limits on its uranium enrichment program that would last up to15 years. Iran appears to be trying to back away from what it agreed to in April, according to Western sources.

• Research and development: The April agreement is vague about what research and development involving uranium enrichment Iran can undertake. The U.S. wants limits Iran says it won't accept.

• Redesign of the Arak reactor: Iran agreed to rebuild the Arak heavy-water reactor based on a design agreed to by both sides, so the reactor will be used for peaceful research. An agreement hasn't been reached on the new design.

What about July 9 and U.S. Congressional review?

After the April 2015 agreement was reached, the U.S. Congress passed legislation about its approval process for apotentialfinal agreement.

Had the negotiators somehow reached a deal by July 9, the review by Congress would have lasted 30 days.

Now, should an agreement be reached, Congressgets 60 days, twice the time for the agreement's opponents to find a way to unravel the deal.

Under the terms of that U.S. law, President Barack Obama would eventually be able to get the treaty through Congress even if he has the support of just one-third of the U.S. Senate. So Congress will require a veto-proof two-thirds majority to enact new sanctions or prevent Obama from suspending existing ones.

If that happens, the U.S. cannot live up to the agreement with Iran, if one is reached.

Obama cannot remove sanctions on Iran during the 60-day review.

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