Israel attacked Iran’s nuclear infrastructure, focusing particularly on its underground uranium enrichment plants.
The Natanz plant in the center of the country suffered severe damage, according to the International Atomic Energy Agency (IAEA).
Another facility, Fordo, is buried deep underground from a mountain. Reaching this underground plant would require more powerful “bunker-busting” bombs, which only the United States possesses.
So what would be the risks of bombing Fordo?
The IAEA described the attacks on Iran’s nuclear facilities as “deeply worrying”.
IAEA Director General Rafael Grossi said on Monday that the military escalation “increases the possibility of a radiological release with serious consequences for people and the environment”.
Uranium enrichment plants are used to stockpile supplies of a particular type (or isotope) of uranium.
“When you dig uranium out of the ground, it comes in two forms: 99.3% is uranium-238 and 0.7%, or roughly one atom in 150, is uranium-235 and this is what is needed to work in a nuclear reactor,” explains Professor Paddy Regan of the University of Surrey and the UK's National Physical Laboratory.
Burst of Energy
The process of nuclear enrichment basically means increasing the amount of uranium-235.
This is achieved by taking uranium in its gaseous form and processing it in centrifuges, Regan explained.
And since uranium-238 is heavier than the uranium-235 required, the two separate as they spin. This is repeated over and over again to increase the enrichment.
Nuclear power plants typically need between 3 to 5 percent of this enriched uranium to generate a controlled nuclear reaction that releases energy.
But when the goal is to make a nuclear weapon, a much higher proportion of uranium-235 is needed: around 90 percent.
Essentially, The more enriched the uranium, the greater the burst of energy as the atoms split.
The IAEA said Iran’s uranium has reached around 60% enrichment, putting it on track to be concentrated enough to make a nuclear weapon.
Nuclear scale
However, firing a rocket at properly stored stockpiles of enriched uranium would not represent a “nuclear incident” on the same scale as disasters at nuclear plants such as Fukushima or Chernobyl.
“Highly enriched uranium is about three times more radioactive than unenriched uranium,” explained Professor Jim Smith of the University of Portsmouth, who has studied the aftermath of the Chernobyl disaster.
“But in fact, on the scale of things, none of them are particularly dense in radioactivity. It wouldn’t cause a major environmental contamination problem,” "We're most concerned about what are called fission products: the elements that uranium decays into when it's in a reactor or a bomb, like radioactive caesium, radioactive strontium, and radioactive iodine. They represent a bigger environmental contamination problem." But since no nuclear reaction is taking place at enrichment plants, and a bomb explosion wouldn't trigger a reaction, these dangerous radioactive "fission products" wouldn't be present, Smith added. However, uranium could be dispersed locally by an explosion. At the Natanz facility, after the bombing, the IAEA found radioactive contamination on site, but warned that radioactivity levels off-site remained unchanged and at normal levels. With uranium, the radiation doesn't travel very far, Professor Claire said. Corkhill, chair in Mineralogy and Radioactive Waste Management at the University of Bristol.
But for people near the site, there could be health risks, she added.
“In terms of toxicity to the human body, you certainly don’t want to inhale uranium particles and you certainly don’t want to ingest them,” she said.
“That’s because uranium particles could get trapped in cells, inside your lungs or your stomach, and slowly decay radioactively, which would cause damage.”
As well as radioactivity, chemical exposure could also be an issue for those nearby.
“If there was an incident and the centrifuges released the uranium hexafluoride, the gas contained within them, then that would be a really serious chemical incident,” said Professor Simon Middleburgh, a nuclear materials scientist at Bangor University in Wales.
“If this uranium hexafluoride comes into contact with moisture in the air, it’s really corrosive and nasty because it can form a very, very strong acid,” he said.
“But it’s not going to have a huge environmental impact beyond the very, very local area.”
The IAEA said its Incident and Emergency Centre is working around the clock and will continue to monitor the status of Iran’s nuclear facilities and the level of radiation at its plants.
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