Tehran: Inspectors from the UN nuclear watchdog arrived in Iran on Saturday to visit the still-unfinished Arak heavy water plant for the first time in more than two years, the Isna news agency reported.

The two inspectors from the International Atomic Energy Agency will begin their work on Sunday at the site, 240 kilometres southwest of the capital, but Isna did not say how long they would be there.

The inspection comes within the framework of a mid-November agreement between Iran and the IAEA that also allows the IAEA access to a uranium mine in Gachin, in the country’s south.

The IAEA regularly visits the works on the reactor, but says it has not received any new design details since 2006. And inspectors have not been to the heavy water plant since August 2011.

The Arak reactor is of concern to the international community because Tehran could theoretically extract weapons-grade plutonium from its spent fuel.

Under a deal reached last month with world powers in Geneva, Iran agreed that it would not commission the reactor or transfer fuel or heavy water to the site for a period of six months.

However, construction delays have effectively made that a moot point, as the authorities had not hoped to finish work before the end of 2014. Subsequently, they said that target would not be met, without giving a new date.

Meanwhile, Iran’s president defended the deal that eases some of the international community’s crippling economic sanctions in return for a freeze on part of the Islamic Republic’s uranium enrichment activities, saying on Saturday that improving the economy is as important as maintaining a peaceful nuclear programme.

Since Iran signed the interim agreement last month with world powers, President Hassan Rouhani has been trying to convince skeptics and hardliners at home that Iran is not compromising on key issues of national sovereignty. It’s a task that will become all the more difficult for the moderate leader as Tehran moves toward a final accord six months from now.

“Nuclear technology and uranium enrichment is our definite right,” Rouhani said in a speech to university students that was broadcast live on state TV. “But progress, better living conditions and welfare for the people is also our definite right. Breaking and dismantling the architecture of the ominous and oppressive sanctions is also our definite right.”

A strict sanction regime levelled by Western powers on Iran over its disputed nuclear programme has taken an immense toll on the nation’s economy, and Rouhani was elected in a landslide earlier this year with the expectation that he would quickly fix the economic malaise. At times, he has tried to frame the debate over the nuclear deal in economic terms, stressing the boost it would give to the economy.

“Centrifuges should spin. But the life of people and the economy also need to spin,” he added. “Without economic might, our national might won’t be enhanced.”

Economists blamed Iran’s economic malaise on a combination of sanctions and mismanagement under Rouhani’s predecessor, Mahmoud Ahmadinejad. But Rouhani has vowed to revive the economy through better management at home and constructive interaction with the outside world.

His speech was interrupted by chants of “moderation, reforms” from supporters and “Death to America” from hard line students who attended the speech. Rouhani paused for seconds when supporters called for the release of opposition leaders while opponents demanded their execution.

“We need domestic unanimity and consensus to reach our goals. So, we should increase our tolerance,” Rouhani said with a smile. “If we can’t resolve a domestic issue through rationality and unanimity, how can we resolve the complicated regional and global issues?”

The six-month interim nuclear deal includes greater access for UN inspectors to Iran’s nuclear facilities, a cap on the level of uranium enrichment in return for a halt to new sanctions and an easing of the existing sanctions.

Hard liners have called the deal a “poisoned chalice” and an agreement that “practically tramples on Iran’s enrichment rights.”

Under the deal, Iran has agreed to halt its 20 per cent enrichment programme, which is just steps away from bomb-making materials, but will continue enrichment up to 5 per cent. It also will convert half of its stockpile of 20 per cent enriched uranium to oxide and dilute the remaining half to 5 per cent.

“You saw what countries got angry with the deal and you saw what a blow was inflicted on the Zionists,” he said, employing the term Iranian leaders use to refer to Israelis. “In the first 100 days of office, we resolved one of [the] knots of the past 10 years and took steps toward constructive interaction with the world to the benefits of the nation.”

Israel has repeatedly criticised the deal and called it a “historic mistake”, saying economic sanctions must be toughened, not eased.