Israeli strikes on Iran's nuclear program are sweeping but can they decimate it?

Israel's sweeping attack across Iran struck at the heart of Tehran's nuclear program, delivering a blow to the country's ability to enrich uranium and potentially setting its nuclear ambitions back by months or years.

As well as killing key military figures and nuclear scientists, the Israeli strikes destroyed part of a plant that was enriching uranium to levels far beyond the requirements for nuclear-fueled power stations. The attacks also destroyed backup power for the underground section of the plant, potentially damaging more sensitive equipment.

Iran's nuclear program has progressed rapidly since 2018, when the U.S. withdrew from a deal to limit Tehran's capacity to enrich uranium, which is necessary to build a nuclear weapon. Iran maintains that its program is peaceful, but the head of the International Atomic Energy Agency has repeatedly warned that the country has enough enriched uranium to make several nuclear bombs if it chose to do so.

Nuclear regulators said the assault was unlikely to lead to increased levels of radiation, even at the site where part of the fuel-enrichment plant was destroyed.

Here's a closer look at the attack and its likely effects on Iran's nuclear efforts.

What impact will the attacks have on Iran's nuclear program?

There is ''no question'' Israel's attacks did substantial damage, said Fabian Hinz, an expert on Iran's nuclear program at the International Institute of Strategic Studies in London.

David Albright, a nuclear weapons expert, speculated that the initial wave of attacks could set back any Iranian attempt to develop a nuclear weapon by about a year.

A key question, Hinz said, is whether Israel also targeted suppliers of specialist components such as centrifuges and subcontractors.

Israel's strategy appears to be to ''destroy the brains'' behind the program and ''as much equipment as possible,'' said Albright, who agreed that Israel has potentially done a ''tremendous amount of damage'' to the program.

Israel is widely believed to be behind a series of attacks in recent years that targeted Iranian nuclear scientists and sabotaged nuclear facilities.

What damage was done to Iran's nuclear facilities?

Hinz suggested a key Israeli goal was to undermine Iran's ability to make centrifuges, which are critical for enriching uranium. Uranium enrichment is a key component of building a nuclear weapon, but Iran would still need to develop a detonator. Delivering it using a missile would require solving further technical challenges.

Iran has two uranium-enrichment sites, and the country said Wednesday that it has built and will activate a third enrichment facility.

Early Friday, Israel struck Iran's main and oldest facility in Natanz, 220 kilometers (135 miles) southeast of Tehran, which was protected by anti-aircraft batteries, fencing and Iran's paramilitary Revolutionary Guard.

The IAEA's chief, Rafael Grossi, told an emergency meeting of the U.N. Security Council on Friday that the above-ground part of the plant where uranium was enriched up to 60% was destroyed, along with electrical infrastructure, including a substation, the main electric power supply building, the emergency power supply and backup generators.

Grossi said there were no changes to radiation levels following the attack or any indication of damage to the underground section of the plant. That part of the facility is buried to protect it from airstrikes and contains the bulk of Natanz's enrichment facilities, with 10,000 centrifuges that enrich uranium up to 5%, Albright said. However, Grossi said, the loss of power may have damaged centrifuges.

There is a good chance the strikes still caused ''massive damage," Hinz said because many of the centrifuges were probably operating at the time of the strike.

Centrifuges, Albright said, ''don't like vibration," and the shock waves or loss of power could break delicate parts when they are rotating at high speed.

What about the Fordo nuclear site?

Most of Iran's centrifuges are in Natanz, the experts said, because a lot of them are required to enrich uranium to 5% — which is the maximum level normally used for nuclear-fueled power stations.

But, buried under a huge mountain at Fordo, around 100 kilometers (60 miles) southwest of Tehran, is another nuclear facility where Iran is also enriching uranium to 60%, which is only a short step away from weapons-grade levels of 90%. According to the IAEA, Tehran has the largest number of its most powerful centrifuges at Fordo.

An Iranian news outlet close to the government reported Friday that two explosions were heard near the Fordo site. But, while Israel could potentially hit the entrance to Fordo and temporarily block access, it is not believed to have the type of earth-penetrating bombs required to blow up the mountain and crack open the nuclear facility inside, Hinz said.

That capacity lies with the U.S., which has developed a massive bomb that can be dropped only from large aircraft that Israel does not have in service, he said.

The potential for more strikes loomed large. Israeli Prime Minister Benjamin Netanyahu has said the attacks will continue ''for as many days at it takes to remove this threat.''

Hinz said the attacks showed Israeli intelligence had ''absolutely exceptional'' knowledge of Iran's nuclear program and the ability to strike at key targets ''with precision.'' That could mean Israel could sabotage the plant, rather than trying to blast the mountain open. Albright suggested Israel could try to cut off electricity to Fordo, which could lead to centrifuges breaking.

Is there risk from radiation?

Although Grossi said part of the enrichment facility at Natanz was destroyed, he noted that radiation levels had not spiked.

Even if radiation did leak, experts said, the amount would be unlikely to pose a risk to people in the region or even those near the facilities that got hit.

''Very little uranium will be released in these kind of attacks,'' Albright said.

Uranium itself is not especially toxic, he said, and is common in parts of the environment. A person standing near an enrichment facility with a leak would probably be exposed to no more radiation than someone who took several transatlantic flights, which receive slightly higher radiation because radiation doses are larger at high altitudes, he said.

In order to become sick, someone would have to ingest large quantities of uranium, Albright said, pointing out that the element can be found naturally in seawater and the earth's crust.

Rather than radiation, the greater risk might be from fluorine, which is used to enrich uranium and could have been deadly to those nearby if released during an attack.

Fluorine is mixed with the uranium during enrichment to turn it into a gas called uranium hexafluoride. It is extremely volatile, will quickly corrode and can burn the skin. It is especially deadly if inhaled.

___

An earlier version of this story corrected that Israel's strikes on Iran's nuclear facilities came early Friday, not Thursday.

___

The Associated Press receives support for nuclear security coverage from the Carnegie Corporation of New York and Outrider Foundation. The AP is solely responsible for all content.

___

Additional AP coverage of the nuclear landscape: https://apnews.com/projects/the-new-nuclear-landscape/