Radiation dangers of three nuclear sites struck by the US

The United States has obliterated three major nuclear sites in Iran, President Donald Trump declared on Sunday about noon AEST.

Even before the US strikes, Rafael Grossi, director-general of the International Atomic Energy Agency, warned Israeli bombardment of nuclear sites had “caused a sharp degradation in nuclear safety and security in Iran”.

US President Donald Trump during an address following the US bombing of three sites in Iran.Credit: Bloomberg

Experts have said chemical contamination was the most likely consequence of damage to Iranian nuclear facilities and the prospect of nuclear fallout or widespread contamination was low.

Strikes had mostly targeted enrichment plants, which used highly pure uranium and didn’t pose much of a radiological hazard, said Richard Wakeford, a professor at the University of Manchester’s Centre for Occupational and Environmental Health, when commenting on earlier Israeli bombings.

One of the US targets, however, was Isfahan, which hosts three research reactors and a nuclear waste site.

“If reactors or reprocessing plants are hit, that could be more of a radiological problem if it causes significant damage because then we could see releases of a range of radionuclides, although presumably on a much smaller scale than from previous reactor accidents,” Wakeford said.

On Saturday (AEST), former nuclear research engineer François Diaz-Maurin, now associate editor at the Bulletin of the Atomic Scientists, analysed the risk posed by damage or misadventure at each nuclear site, including the three targeted by US bombs.

Isfahan

The US struck the massive nuclear technology site at Isfahan with a barrage of submarine-launched Tomahawk missiles, The New York Times reported. Diaz-Maurin rated the risk of something going wrong at Isfahan as “moderate”.

The technology centre has three small Chinese-built research reactors, a lab which makes the uranium hexafluoride gas, a reactor fuel manufacturing plant and a nuclear waste storage facility.

In 2021, the IAEA found a plant at Isfahan created uranium metal, which can be used to make the core of a nuclear weapon.

A photo of the uranium conversion facility inside the Isfahan nuclear centre from 2005.Credit: AP

“Uranium metal is less chemically hazardous than uranium hexafluoride gas, but it poses a significant radiation risk,” Diaz-Maurin said.

He warned the radiological consequences of a strike on research reactors could be significant.

The IAEA said there was no off-site rise in radiation levels after earlier Israeli bombing of Isfahan.

Natanz

Risk of radioactive contamination from the bombing of Iran’s main facility for uranium enrichment at Natanz is very low, according to Diaz-Maurin.

Enrichment occurs is when uranium is centrifuged at high speeds to process it into weapons-grade material. About 15,000 underground enrichment centrifuges were already destroyed or badly damaged by Israeli bombing.

The centrifuges contain tiny amounts of uranium hexafluoride, which is one of the most corrosive substances on Earth. The gas also creates toxic forms of fluoride when it comes into contact with moisture.

A hexafluoride gas storage facility had already been damaged, resulting in radiological and chemical contamination contained at the site.

“The main risk inside the storage facility is the chemical toxicity of uranium hexafluoride gas and fluoride compounds generated in contact with water,” Diaz-Maurin wrote. “The radiological risk from enriched uranium at Natanz is likely to be much smaller than the chemical toxicity from the fluorine.”

He warned that although uranium hexafluoride was not directly fissile – or able to undergo nuclear fission – damage could cause a dangerous explosion.

“If moisture enters transport or storage cylinders, uranium, especially enriched uranium, becomes more reactive.

“This could potentially lead to a chemical explosion of the cylinders, resulting in a significant dispersion of uranium hexafluoride gas into the facility and possibly into the environment – a scenario possible even without an attack.”

Experts told Reuters the slightly radioactive gas did not tend to travel far if released.

Fordow

B-2 bombers struck the underground Fordow facility with at least six 30,000-pound bunker-buster bombs, The New York Times reported.

Risk of off-site radiation contamination from the facility is also very low because it’s an enrichment plant. Fordow is built within a mountain 90 metres underground, further reducing the risk contamination would spread.

“Should a subterranean enrichment facility or reactor be hit by one or more bunker-busters, it is unlikely that there would be significant contamination beyond the confines of the site,” said Dr Simon Bennett, director of the civil safety and security unit at the University of Leicester.

Experts are most concerned about the prospect of a strike on Bushehr nuclear power plant. If a strike pierced the plant’s nuclear reactor or interrupted power supply, the plant could release radioactive material into the atmosphere, contaminate the waters of the Gulf and trigger evacuation of people hundreds of kilometres from the site, Grossi warned.

He underlined the IAEA’s belief that armed attacks on nuclear facilities should never take place.

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