Iran uranium enrichment: why do the nuclear deal limits matter?

Iran has announced that it is to produce 5 per cent enriched uranium in the second breach of the 2015 nuclear deal — but what does that mean?

Supertanker Grace 1 off the coast of Gibraltar. AFP

Supertanker Grace 1 off the coast of Gibraltar. AFP

A ship approaches supertanker Grace 1 off the coast of Gibraltar. AFP

A British Police ship patrols near supertanker Grace 1 off the coast of Gibraltar. AFP

Supertanker Grace 1 off the coast of Gibraltar. AFP

A ship approaches supertanker Grace 1 off the coast of Gibraltar. AFP

A British Royal Navy ship patrols near supertanker Grace 1. AFP

Crew members walk down a ladder on board supertanker Grace 1 off the coast of Gibraltar. AFP

Crew members walk on board supertanker Grace 1 off the coast of Gibraltar. AFP

Iran has announced that it is to begin enriching uranium beyond the 3.67 per cent cap laid out in the 2015 nuclear deal, potentially breaching the agreement for a second time in weeks. It says the move is necessary to produce fuel for a nuclear power plant, but it comes amid tension with the US, with Tehran putting pressure on the European signatories to the deal to combat US sanctions.

What is enriched uranium?

Uranium is composed of various isotopes. Uranium-235, which makes up about 0.7 per cent of mined uranium, is the most important when it comes to nuclear energy. Enrichment is the process of increasing the level of Uranium-235 through isotope separation. Uranium enriched to between 3 and 5 per cent is used in nuclear power plants, where as 90 per cent and above is considered weapons-grade.

What was agreed under the 2015 deal?

The deal, signed by the US, UK, Russia, France, China and Germany, aims to curb Iran's perceived nuclear ambitions by extending the time it would need to produce a nuclear weapon from roughly two or three months to a year. The deal states that until 2031, Iran's stockpile must not exceed 300 kilgrams of 3.67 per cent enriched uranium.

Before the agreement, Iran was reaching about 20 per cent and had a stockpile of 10,000kg of higher-enriched uranium. Twenty per cent enriched uranium can be used in research reactors or for medical purposes.

Iran must also refrain from commissioning or fuelling the Arak Nuclear Plant reactor, a heavy-water nuclear facility. A by-product of heavy-water reactors is plutonium that is suitable for a nuclear bomb, and Iran is not allowed to build more heavy-water reactors or accumulate a stockpile of more than 130 tonnes of heavy-water for 15 years from the deal's implementation in 2016.

Prior to 2015, Iran had two enrichment facilities: Natanz and Fordo. No enrichment is permitted at Fordo until 2031 and the number of centrifuges — used in the enrichment process — at Natanz has been limited.

Has Iran broken the deal before?

The country announced last week that it has already exceeded the 300kg low-enriched uranium stockpile limit. The amount of heavy water that it is allowed under the agreement was also twice breached early on, but quickly resolved.

The United Nations’ nuclear watchdog has also said Iran’s heavy water stockpile was 125.2 tonnes as of May 26, up from 124.8 tonnes in February.

Do the breaches mean Iran is able to build a nuclear bomb?

Not yet, it is a still a long way off from the 90 per cent needed for a bomb. Iran said on Sunday it is going to enrich to 5 per cent, but for peaceful aims.

“We need uranium enriched to 5 per cent for use in the Bushehr [power plant] and this is a completely peaceful purpose,” said Ali Akbar Velayati, a senior adviser to Supreme Leader Ayatollah Ali Khamenei.

What does Iran want?

Iran’s main demand is to be allowed to sell its oil at the levels it was before the US pulled out of the deal in May 2018 and restored sanctions. Exports have fallen to about 300,000 barrels per day, compared with the 2.5 million barrels Iran was selling in April 2018 and the Iranian economy has slumped as a result. Tehran says it will now continue to reduce its commitments to the 2015 deal every 60 days.

European leaders have suggested that they view Iran’s moves as ultimately reversible and part of a negotiating tactic. They have signalled that they won’t rush to reimpose sanctions, but they’ll find it increasingly hard to resist pressure from the Trump administration if Iran abandons multiple commitments.